Articles de revues : « H5N1 influenza vaccine »

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Chua, Tze-Hoong, Connie Y. H. Leung, H. E. Fang, Chun-Kin Chow, Siu-Kit Ma, Sin-Fun Sia, Iris H. Y. Ng et al. « Evaluation of a Subunit H5 Vaccine and an Inactivated H5N2 Avian Influenza Marker Vaccine in Ducks Challenged with Vietnamese H5N1 Highly Pathogenic Avian Influenza Virus ». Influenza Research and Treatment 2010 (27 juin 2010) : 1–10. http://dx.doi.org/10.1155/2010/489213.

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The protective efficacy of a subunit avian influenza virus H5 vaccine based on recombinant baculovirus expressed H5 haemagglutinin antigen and an inactivated H5N2 avian influenza vaccine combined with a marker antigen (tetanus toxoid) was compared with commercially available inactivated H5N2 avian influenza vaccine in young ducks. Antibody responses, morbidity, mortality, and virus shedding were evaluated after challenge with a Vietnamese clade 1 H5N1 HPAI virus [A/VN/1203/04 (H5N1)] that was known to cause a high mortality rate in ducks. All three vaccines, administered with water-in-oil adjuvant, provided significant protection and dramatically reduced the duration and titer of virus shedding in the vaccinated challenged ducks compared with unvaccinated controls. The H5 subunit vaccine was shown to provide equivalent protection to the other two vaccines despite the H5 antibody responses in subunit vaccinated ducks being significantly lower prior to challenge. Ducks vaccinated with the H5N2 marker vaccine consistently produced antitetanus toxoid antibody. The two novel vaccines have attributes that would enhance H5N1 avian influenza surveillance and control by vaccination in small scale and village poultry systems.

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Nuñez, Ivette A., Ying Huang et Ted M. Ross. « Next-Generation Computationally Designed Influenza Hemagglutinin Vaccines Protect against H5Nx Virus Infections ». Pathogens 10, n^o 11 (20 octobre 2021) : 1352. http://dx.doi.org/10.3390/pathogens10111352.

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H5N1 COBRA hemagglutinin (HA) sequences, termed human COBRA-2 HA, were constructed through layering of HA sequences from viruses isolated from humans collected between 2004–2007 using only clade 2 strains. These COBRA HA proteins, when expressed on the surface of virus-like particles (VLP), elicited protective immune responses in mice, ferrets, and non-human primates. However, these vaccines were not as effective at inducing neutralizing antibodies against newly circulating viruses. Therefore, COBRA HA-based vaccines were updated in order to elicit protective antibodies against the current circulating clades of H5Nx viruses. Next-generation COBRA HA vaccines were designed to encompass the newly emerging viruses circulating in wild avian populations. HA amino acid sequences from avian and human H5 influenza viruses isolated between 2011–2017 were downloaded from the GISAID (Global Initiative on Sharing All Influenza Data). Mice were vaccinated with H5 COBRA rHA that elicited antibodies with hemagglutinin inhibition (HAI) activity against H5Nx viruses from five clades. The H5 COBRA rHA vaccine, termed IAN8, elicited protective immune responses against mice challenged with A/Sichuan/26621/2014 and A/Vietnam/1203/2004. This vaccine elicited antibodies with HAI activity against viruses from clades 2.2, 2.3.2.1, 2.3.4.2, 2.2.1 and 2.2.2. Lungs from vaccinated mice had decreased viral titers and the levels of cellular infiltration in mice vaccinated with IAN-8 rHA were similar to mice vaccinated with wild-type HA comparator vaccines or mock vaccinated controls. Overall, these next-generation H5 COBRA HA vaccines elicited protective antibodies against both historical H5Nx influenza viruses, as well as currently circulating clades of H5N1, H5N6, and H5N8 influenza viruses.

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Takada, Ayato, Noritaka Kuboki, Katsunori Okazaki, Ai Ninomiya, Hiroko Tanaka, Hiroichi Ozaki, Shigeyuki Itamura et al. « Avirulent Avian Influenza Virus as a Vaccine Strain against a Potential Human Pandemic ». Journal of Virology 73, n^o 10 (1 octobre 1999) : 8303–7. http://dx.doi.org/10.1128/jvi.73.10.8303-8307.1999.

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ABSTRACT In the influenza H5N1 virus incident in Hong Kong in 1997, viruses that are closely related to H5N1 viruses initially isolated in a severe outbreak of avian influenza in chickens were isolated from humans, signaling the possibility of an incipient pandemic. However, it was not possible to prepare a vaccine against the virus in the conventional embryonated egg system because of the lethality of the virus for chicken embryos and the high level of biosafety therefore required for vaccine production. Alternative approaches, including an avirulent H5N4 virus isolated from a migratory duck as a surrogate virus, H5N1 virus as a reassortant with avian virus H3N1 and an avirulent recombinant H5N1 virus generated by reverse genetics, have been explored. All vaccines were formalin inactivated. Intraperitoneal immunization of mice with each of vaccines elicited the production of hemagglutination-inhibiting and virus-neutralizing antibodies, while intranasal vaccination without adjuvant induced both mucosal and systemic antibody responses that protected the mice from lethal H5N1 virus challenge. Surveillance of birds and animals, particularly aquatic birds, for viruses to provide vaccine strains, especially surrogate viruses, for a future pandemic is stressed.

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Banner, David, et Alyson Ann Kelvin. « The current state of H5N1 vaccines and the use of the ferret model for influenza therapeutic and prophylactic development ». Journal of Infection in Developing Countries 6, n^o 06 (15 mai 2012) : 465–69. http://dx.doi.org/10.3855/jidc.2666.

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Highly pathogenic avian influenza H5N1 is a threat to global public health as a natural pandemic causing agent but has recently been considered a bioterrorism concern. The evolving view of the H5N1 virus necessitates the re-evaluation of the current status of H5N1 therapeutics and prophylactics, in particular the preparation of viable H5N1 vaccination strategies as well as the use of ferrets in influenza research. Here the highly pathogenic H5N1 virus dilemma is discussed in context with the current H5N1 vaccine status and the use of the ferret model. Previously, the development of various H5N1 vaccine platforms have been attempted, many of them tested in the ferret model, including vector vaccines, adjuvant vaccines, DNA vaccines, and reverse engineered vaccines. Moreover, as ferrets are a superlative animal model for influenza investigation and vaccine testing, it is imperative that this model is recognized for its uses in prophylactic development and not only as an agent for creating transmissible influenza viruses. Elucidating the ferret immune response and creating ferret immune reagents remain important goals in conjunction with the development and manufacture of H5N1 vaccines. In summary, an efficacious H5N1 vaccine is urgently needed and the ferret model remains an appropriate model for its development.

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Ali, Ahmed, Marwa Safwat, Walid H. Kilany, Abdou Nagy, Awad A. Shehata, Mohamed A. Zain El-Abideen, Al-Hussien M. Dahshan et Abdel-Satar A. Arafa. « Combined H5ND inactivated vaccine protects chickens against challenge by different clades of highly pathogenic avian influenza viruses subtype H5 and virulent Newcastle disease virus ». Veterinary World 12, n^o 1 (janvier 2019) : 97–105. http://dx.doi.org/10.14202/vetworld.2019.97-105.

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Aim: The aim of the current study was to evaluate the efficacy of a trivalent-inactivated oil-emulsion vaccine against challenge by different clades highly pathogenic avian influenza (HPAI) viruses including HPAI-H5N8 and the virulent genotype VII Newcastle disease virus (NDV) (vNDV). Materials and Methods: The vaccine studied herein is composed of reassortant AI viruses rgA/Chicken/Egypt/ ME1010/2016 (clade 2.2.1.1), H5N1 rgA/Chicken/Egypt/RG-173CAL/2017 (clade 2.2.1.2), and "NDV" (LaSota NDV/ CK/Egypt/11478AF/11); all used at a concentration of 108 EID50/bird and mixed with Montanide-ISA70 oil adjuvant. Two-week-old specific pathogen free (SPF) chickens were immunized subcutaneously with 0.5 ml of the vaccine, and hemagglutination inhibition (HI) antibody titers were monitored weekly. The intranasal challenge was conducted 4 weeks post-vaccination (PV) using 106 EID50/0.1 ml of the different virulent HPAI-H5N1 viruses representing clades 2.2.1, 2.2.1.1, 2.2.1.2, 2.3.4.4b-H5N8, and the vNDV. Results: The vaccine induced HI antibody titers of >6log2 against both H5N1 and NDV viruses at 2 weeks PV. Clinical protection against all HPAI H5N1 viruses and vNDV was 100%, except for HPAI H5N1 clade-2.2.1 and HPAI H5N8 clade- 2.3.4.4b viruses that showed 93.3% protection. Challenged SPF chickens showed significant decreases in the virus shedding titers up to <3log10 compared to challenge control chickens. No virus shedding was detected 6 "days post-challenge" in all vaccinated challenged groups. Conclusion: Our results indicate that the trivalent H5ND vaccine provides significant clinical protection against different clades of the HPAI viruses including the newly emerging H5N8 HPAI virus. Availability of such potent multivalent oil-emulsion vaccine offers an effective tool against HPAI control in endemic countries and promises simpler vaccination programs.

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Lei, Han, Sha Jin, Erik Karlsson, Stacey Schultz-Cherry et Kaiming Ye. « Yeast Surface-Displayed H5N1 Avian Influenza Vaccines ». Journal of Immunology Research 2016 (2016) : 1–12. http://dx.doi.org/10.1155/2016/4131324.

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Highly pathogenic H5N1 avian influenza viruses pose a pandemic threat to human health. A rapid vaccine production against fast outbreak is desired. We report, herein, a paradigm-shift influenza vaccine technology by presenting H5N1 hemagglutinin (HA) to the surface of yeast. We demonstrated, for the first time, that the HA surface-presented yeast can be used as influenza vaccines to elicit both humoral and cell-mediated immunity in mice. The HI titer of antisera reached up to 128 in vaccinated mice. A high level of H5N1 HA-specific IgG1 and IgG2a antibody production was detected after boost immunization. Furthermore, we demonstrated that the yeast surface-displayed HA preserves its antigenic sites. It preferentially binds to both avian- and human-type receptors. In addition, the vaccine exhibited high cross-reactivity to both homologous and heterologous H5N1 viruses. A high level production of anti-HA antibodies was detected in the mice five months after vaccination. Finally, our animal experimental results indicated that the yeast vaccine offered complete protection of mice from lethal H5N1 virus challenge. No severe side effect of yeast vaccines was noted in animal studies. This new technology allows for rapid and large-scale production of influenza vaccines for prepandemic preparation.

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Kodihalli, Shantha, Hideo Goto, Darwyn L. Kobasa, Scott Krauss, Yoshihiro Kawaoka et Robert G. Webster. « DNA Vaccine Encoding Hemagglutinin Provides Protective Immunity against H5N1 Influenza Virus Infection in Mice ». Journal of Virology 73, n^o 3 (1 mars 1999) : 2094–98. http://dx.doi.org/10.1128/jvi.73.3.2094-2098.1999.

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ABSTRACT In Hong Kong in 1997, a highly lethal H5N1 avian influenza virus was apparently transmitted directly from chickens to humans with no intermediate mammalian host and caused 18 confirmed infections and six deaths. Strategies must be developed to deal with this virus if it should reappear, and prospective vaccines must be developed to anticipate a future pandemic. We have determined that unadapted H5N1 viruses are pathogenic in mice, which provides a well-defined mammalian system for immunological studies of lethal avian influenza virus infection. We report that a DNA vaccine encoding hemagglutinin from the index human influenza isolate A/HK/156/97 provides immunity against H5N1 infection of mice. This immunity was induced against both the homologous A/HK/156/97 (H5N1) virus, which has no glycosylation site at residue 154, and chicken isolate A/Ck/HK/258/97 (H5N1), which does have a glycosylation site at residue 154. The mouse model system should allow rapid evaluation of the vaccine’s protective efficacy in a mammalian host. In our previous study using an avian model, DNA encoding hemagglutinin conferred protection against challenge with antigenic variants that differed from the primary antigen by 11 to 13% in the HA1 region. However, in our current study we found that a DNA vaccine encoding the hemagglutinin from A/Ty/Ir/1/83 (H5N8), which differs from A/HK/156/97 (H5N1) by 12% in HA1, prevented death but not H5N1 infection in mice. Therefore, a DNA vaccine made with a heterologous H5 strain did not prevent infection by H5N1 avian influenza viruses in mice but was useful in preventing death.

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Sun, Weiyang, Zhenfei Wang, Yue Sun, Dongxu Li, Menghan Zhu, Menglin Zhao, Yutian Wang et al. « Safety, Immunogenicity, and Protective Efficacy of an H5N1 Chimeric Cold-Adapted Attenuated Virus Vaccine in a Mouse Model ». Viruses 13, n^o 12 (3 décembre 2021) : 2420. http://dx.doi.org/10.3390/v13122420.

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H5N1 influenza virus is a threat to public health worldwide. The virus can cause severe morbidity and mortality in humans. We constructed an H5N1 influenza candidate virus vaccine from the A/chicken/Guizhou/1153/2016 strain that was recommended by the World Health Organization. In this study, we designed an H5N1 chimeric influenza A/B vaccine based on a cold-adapted (ca) influenza B virus B/Vienna/1/99 backbone. We modified the ectodomain of H5N1 hemagglutinin (HA) protein, while retaining the packaging signals of influenza B virus, and then rescued a chimeric cold-adapted H5N1 candidate influenza vaccine through a reverse genetic system. The chimeric H5N1 vaccine replicated well in eggs and the Madin-Darby Canine Kidney cells. It maintained a temperature-sensitive and cold-adapted phenotype. The H5N1 vaccine was attenuated in mice. Hemagglutination inhibition (HAI) antibodies, micro-neutralizing (MN) antibodies, and IgG antibodies were induced in immunized mice, and the mucosal IgA antibody responses were detected in their lung lavage fluids. The IFN-γ-secretion and IL-4-secretion by the mouse splenocytes were induced after stimulation with the specific H5N1 HA protein. The chimeric H5N1 candidate vaccine protected mice against lethal challenge with a wild-type highly pathogenic avian H5N1 influenza virus. The chimeric H5 candidate vaccine is thus a potentially safe, attenuated, and reassortment-incompetent vaccine with circulating A viruses.

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Skarlupka, Amanda L., Xiaojian Zhang, Uriel Blas-Machado, Spencer F. Sumner et Ted M. Ross. « Multi-Influenza HA Subtype Protection of Ferrets Vaccinated with an N1 COBRA-Based Neuraminidase ». Viruses 15, n^o 1 (9 janvier 2023) : 184. http://dx.doi.org/10.3390/v15010184.

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The influenza neuraminidase (NA) is a promising target for next-generation vaccines. Protection induced by vaccination with the computationally optimized broadly reactive NA antigen (N1-I COBRA NA) was characterized in both influenza serologically naive and pre-immune ferret models following H1N1 (A/California/07/2009, CA/09) or H5N1 (A/Vietnam/1203/2004, Viet/04) influenza challenges. The N1-I COBRA NA vaccine elicited antibodies with neutralizing ELLA activity against both seasonal and pandemic H1N1 influenza, as well as the H5N1 influenza virus. In both models, N1-I COBRA NA-vaccinated ferrets that were challenged with CA/09 virus had similar morbidity (weight loss and clinical symptoms) as ferrets vaccinated with the CA/09 HA control vaccine. There were significantly reduced viral titers compared to the mock-vaccinated control animals. Ferrets vaccinated with N1-I COBRA NA or Viet/04 NA vaccines were protected against the H5N1 virus infection with minimal clinical symptoms and negligible weight loss. In contrast, ferrets vaccinated with the CA/09 NA vaccine lost ~10% of their original body weight with 25% mortality. Vaccination with either HA or NA vaccines did not inhibit contact transmission of CA/09 virus to naïve cage mates. Overall, the N1-I COBRA vaccine elicited protective immune responses against both H1N1 and H5N1 infections and partially mitigated disease in contact-transmission receiving ferrets. These results indicate that the N1-I COBRA NA performed similarly to the CA/09 HA and NA positive controls. Therefore, the N1-I COBRA NA alone induces protection against viruses from both H5N1 and H1N1 subtypes, indicating its value as a vaccine component in broadly protective influenza vaccines.

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Thi Dung, Luu, Doan Huu Thien, Nguyen Thi Ly, Nguyen Thi Hong Dinh, Be Thi Tham, Nguyen Hoang Tung et Pham Van Hung. « RT-PCR test for specific indentification of influenzavirus (A/H5N1) in vaccine ». JOURNAL OF CONTROL VACCINES AND BIOLOGICALS, n^o 1 (31 décembre 2021) : 66–77. http://dx.doi.org/10.56086/jcvb.vi1.6.

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RT-PCR (Reverse transcription - Polymerase Chain Reaction) is applied to determine the presence of influenza virus A/ H5N1 in vaccine, and to develop an identity process for specific virus strain A/H5N1 in influenza vaccine A/H5N1. Selected samples included: Ivacflu-A/H5N1 vaccine (Institute of Vaccines and Biologicals), Vaxigrip vaccine (Sanofi Pasteur), Influenza virus strain A/ Vietnam/1194/2004(A/H5N1) (NIBSC) was used as positive control; vaccine Varivax (MSD) and DNA/RNA free water was used as negative controls. The results showed that virus strain A/H5N1 was identified as production of RT-PCR that were positive with amplified primer pairs of 2 specific gene sequences of HA whose length 428 and 249 bp. Before starting RT-PCR, it was necessary to eliminate aluminum and the components of RT-PCR reaction included: 5X QIAGEN OneStep RT-PCR Buffer(5µl); dNTP (1µl); forward and reverse primers (1,5 µl); Enzyme (1 µl), H2 O (10 µl), ARN template (5 µl) and thermal cycle of RT- PCR reaction was: 50oC (30 minutes); 95OC (15 minutes); 94OC (30 seconds); 55OC (30 seconds); 72OC (1 minute); 72OC (10 minutes), 45 cycles.

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Bodewes, R., J. H. C. M. Kreijtz, G. van Amerongen, M. M. Geelhoed-Mieras, R. J. Verburgh, J. G. M. Heldens, J. Bedwell et al. « A Single Immunization with CoVaccine HT-Adjuvanted H5N1 Influenza Virus Vaccine Induces Protective Cellular and Humoral Immune Responses in Ferrets ». Journal of Virology 84, n^o 16 (2 juin 2010) : 7943–52. http://dx.doi.org/10.1128/jvi.00549-10.

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ABSTRACT Highly pathogenic avian influenza A viruses of the H5N1 subtype continue to circulate in poultry, and zoonotic transmissions are reported frequently. Since a pandemic caused by these highly pathogenic viruses is still feared, there is interest in the development of influenza A/H5N1 virus vaccines that can protect humans against infection, preferably after a single vaccination with a low dose of antigen. Here we describe the induction of humoral and cellular immune responses in ferrets after vaccination with a cell culture-derived whole inactivated influenza A virus vaccine in combination with the novel adjuvant CoVaccine HT. The addition of CoVaccine HT to the influenza A virus vaccine increased antibody responses to homologous and heterologous influenza A/H5N1 viruses and increased virus-specific cell-mediated immune responses. Ferrets vaccinated once with a whole-virus equivalent of 3.8 μg hemagglutinin (HA) and CoVaccine HT were protected against homologous challenge infection with influenza virus A/VN/1194/04. Furthermore, ferrets vaccinated once with the same vaccine/adjuvant combination were partially protected against infection with a heterologous virus derived from clade 2.1 of H5N1 influenza viruses. Thus, the use of the novel adjuvant CoVaccine HT with cell culture-derived inactivated influenza A/H5N1 virus antigen is a promising and dose-sparing vaccine approach warranting further clinical evaluation.

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Ducatez, Mariette F., Justin Bahl, Yolanda Griffin, Evelyn Stigger-Rosser, John Franks, Subrata Barman, Dhanasekaran Vijaykrishna et al. « Feasibility of reconstructed ancestral H5N1 influenza viruses for cross-clade protective vaccine development ». Proceedings of the National Academy of Sciences 108, n^o 1 (20 décembre 2010) : 349–54. http://dx.doi.org/10.1073/pnas.1012457108.

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Since the reemergence of highly pathogenic H5N1 influenza viruses in humans in 2003, these viruses have spread throughout avian species in Asia, Europe, and Africa. Their sustained circulation has resulted in the evolution of phylogenetically diverse lineages. Viruses from these lineages show considerable antigenic variation, which has confounded vaccine planning efforts. We reconstructed ancestral protein sequences at several nodes of the hemagglutinin (HA) and neuraminidase (NA) gene phylogenies that represent ancestors to diverse H5N1 virus clades. By using the same methods that have been used to generate currently licensed inactivated H5N1 vaccines, we were able to produce a panel of replication competent influenza viruses containing synthesized HA and NA genes representing the reconstructed ancestral proteins. We identified two of these viruses that showed promising in vitro cross-reactivity with clade 1, 2.1, 2.2, 2.3.4, and 4 viruses. To confirm that vaccine antigens derived from these viruses were able to elicit functional antibodies following immunization, we created whole-virus vaccines and compared their protective efficacy versus that of antigens from positive control, naturally occurring, and broadly reactive H5N1 viruses. The ancestral viruses’ vaccines provided robust protection against morbidity and mortality in ferrets challenged with H5N1 strains from clades 1, 2.1, and 2.2 in a manner similar to those based on the control strains. These findings provide proof of principle that viable, computationally derived vaccine seed viruses can be constructed within the context of currently licensed vaccine platforms. Such technologies should be explored to enhance the cross reactivity and availability of H5N1 influenza vaccines.

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Zeng, Xianying, Pucheng Chen, Liling Liu, Guohua Deng, Yanbing Li, Jianzhong Shi, Huihui Kong et al. « Protective Efficacy of an H5N1 Inactivated Vaccine Against Challenge with Lethal H5N1, H5N2, H5N6, and H5N8 Influenza Viruses in Chickens ». Avian Diseases 60, n^o 1s (mai 2016) : 253–55. http://dx.doi.org/10.1637/11179-052015-resnoter.

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Mayrhofer, Josef, Sogue Coulibaly, Annett Hessel, Georg W. Holzer, Michael Schwendinger, Peter Brühl, Marijan Gerencer et al. « Nonreplicating Vaccinia Virus Vectors Expressing the H5 Influenza Virus Hemagglutinin Produced in Modified Vero Cells Induce Robust Protection ». Journal of Virology 83, n^o 10 (11 mars 2009) : 5192–203. http://dx.doi.org/10.1128/jvi.02081-08.

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ABSTRACT The timely development of safe and effective vaccines against avian influenza virus of the H5N1 subtype will be of the utmost importance in the event of a pandemic. Our aim was first to develop a safe live vaccine which induces both humoral and cell-mediated immune responses against human H5N1 influenza viruses and second, since the supply of embryonated eggs for traditional influenza vaccine production may be endangered in a pandemic, an egg-independent production procedure based on a permanent cell line. In the present article, the generation of a complementing Vero cell line suitable for the production of safe poxviral vaccines is described. This cell line was used to produce a replication-deficient vaccinia virus vector H5N1 live vaccine, dVV-HA5, expressing the hemagglutinin of a virulent clade 1 H5N1 strain. This experimental vaccine was compared with a formalin-inactivated whole-virus vaccine based on the same clade and with different replicating poxvirus-vectored vaccines. Mice were immunized to assess protective immunity after high-dose challenge with the highly virulent A/Vietnam/1203/2004(H5N1) strain. A single dose of the defective live vaccine induced complete protection from lethal homologous virus challenge and also full cross-protection against clade 0 and 2 challenge viruses. Neutralizing antibody levels were comparable to those induced by the inactivated vaccine. Unlike the whole-virus vaccine, the dVV-HA5 vaccine induced substantial amounts of gamma interferon-secreting CD8 T cells. Thus, the nonreplicating recombinant vaccinia virus vectors are promising vaccine candidates that induce a broad immune response and can be produced in an egg-independent and adjuvant-independent manner in a proven vector system.

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Lu, Xiuhua, Terrence M. Tumpey, Timothy Morken, Sherif R. Zaki, Nancy J. Cox et Jacqueline M. Katz. « A Mouse Model for the Evaluation of Pathogenesis and Immunity to Influenza A (H5N1) Viruses Isolated from Humans ». Journal of Virology 73, n^o 7 (1 juillet 1999) : 5903–11. http://dx.doi.org/10.1128/jvi.73.7.5903-5911.1999.

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ABSTRACT During 1997 in Hong Kong, 18 human cases of respiratory illness, including 6 fatalities, were caused by highly pathogenic avian influenza A (H5N1) viruses. Since H5 viruses had previously been isolated only from avian species, the outbreak raised questions about the ability of these viruses to cause severe disease and death in humans. To better understand the pathogenesis and immunity to these viruses, we have used the BALB/c mouse model. Four H5N1 viruses replicated equally well in the lungs of mice without prior adaptation but differed in lethality for mice. H5N1 viruses that were highly lethal for mice were detected in multiple organs, including the brain. This is the first demonstration of an influenza A virus that replicates systemically in a mammalian species and is neurotropic without prior adaptation. The mouse model was also used to evaluate a strategy of vaccination against the highly pathogenic avian H5N1 viruses, using an inactivated vaccine prepared from nonpathogenic A/Duck/Singapore-Q/F119-3/97 (H5N3) virus that was antigenically related to the human H5N1 viruses. Mice administered vaccine intramuscularly, with or without alum, were completely protected from lethal challenge with H5N1 virus. Protection from infection was also observed in 70% of animals administered vaccine alone and 100% of mice administered vaccine with alum. The protective effect of vaccination correlated with the level of virus-specific serum antibody. These results suggests a strategy of vaccine preparedness for rapid intervention in future influenza pandemics that uses antigenically related nonpathogenic viruses as vaccine candidates.

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Masseoud, Feda, Ioanna Skountzou, Nigel Temperton et Joshy Jacob. « Investigating original antigenic sin responses to H5N1 influenza viruses (92.19) ». Journal of Immunology 184, n^o 1_Supplement (1 avril 2010) : 92.19. http://dx.doi.org/10.4049/jimmunol.184.supp.92.19.

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Abstract H5N1 influenza A virus remains a global threat since its outbreak in 1997. Its re-emergence in 2003 spread from Asia to Europe, the Middle-East and Africa, raising concerns of a possible pandemic. While stockpiling of H5N1 prepandemic vaccines has been initiated, strain prediction is difficult due to the emergence of distinct clades/subclades. Antigenic variation between vaccine and pandemic strains may confer cross-protection or result in antigenic sin, in which the immune response is directed against the original strain rather than the novel protective antigenic determinants. Observed between strains that have undergone antigenic drift, this misdirected response may compromise protective immunity. This study was carried out to determine the extent to which antigenic sin interferes with immune responses to the potentially pandemic influenza H5 subtype. We immunized mice with a DNA vaccine encoding the full length HA from influenza A/Vietnam/1194 followed by a vaccine encoding HA of drifted H5N1 strains, ranging in genetic identity from 100%- 88%. We are currently assessing responses directed against either the primary or the drifted strain by microneutralization using a pseudotyped lentivirus bearing HA from the respective H5N1 strains. By examining antigenic sin due to H5N1 viruses, we can better understand the behavior of the virus as it circulates in the human population, and therefore improve preparedness in the context of H5N1 vaccine development and pandemic planning.

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Chen, Po-Ling, Alan Yung-Chih Hu, Chun-Yang Lin, Tsai-Chuan Weng, Chia-Chun Lai, Yu-Fen Tseng, Ming-Chu Cheng et al. « Development of American-Lineage Influenza H5N2 Reassortant Vaccine Viruses for Pandemic Preparedness ». Viruses 11, n^o 6 (11 juin 2019) : 543. http://dx.doi.org/10.3390/v11060543.

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Novel low-pathogenic avian influenza (LPAI) H5N2 viruses hit poultry farms in Taiwan in 2003, and evolved into highly pathogenic avian influenza (HPAI) viruses in 2010. These viruses are reassortant viruses containing HA and NA genes from American-lineage H5N2 and six internal genes from local H6N1 viruses. According to a serological survey, the Taiwan H5N2 viruses can cause asymptomatic infections in poultry workers. Therefore, a development of influenza H5N2 vaccines is desirable for pandemic preparation. In this study, we employed reverse genetics to generate a vaccine virus having HA and NA genes from A/Chicken/CY/A2628/2012 (E7, LPAI) and six internal genes from a Vero cell-adapted high-growth H5N1 vaccine virus (Vero-15). The reassortant H5N2 vaccine virus, E7-V15, presented high-growth efficiency in Vero cells (512 HAU, 107.6 TCID50/mL), and passed all tests for qualification of candidate vaccine viruses. In ferret immunization, two doses of inactivated whole virus antigens (3 μg of HA protein) adjuvanted with alum could induce robust antibody response (HI titre 113.14). In conclusion, we have established reverse genetics to generate a qualified reassortant H5N2 vaccine virus for further development.

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Bihari, Iván, Gyula Pánczél, Jozsef Kovacs, Jenny Beygo et Elena Fragapane. « Assessment of Antigen-Specific and Cross-Reactive Antibody Responses to an MF59-Adjuvanted A/H5N1 Prepandemic Influenza Vaccine in Adult and Elderly Subjects ». Clinical and Vaccine Immunology 19, n^o 12 (17 octobre 2012) : 1943–48. http://dx.doi.org/10.1128/cvi.00373-12.

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ABSTRACTPreparedness against an A/H5N1 influenza pandemic requires well-tolerated, effective vaccines which provide both vaccine strain-specific and heterologous, cross-clade protection. This study was conducted to assess the immunogenicity and safety profile of an MF59-adjuvanted, prepandemic influenza vaccine containing A/turkey/Turkey/01/2005 (H5N1) strain viral antigen. A total of 343 participants, 194 adults (18 to 60 years) and 149 elderly individuals (≥61 years), received two doses of the investigational vaccine given 3 weeks apart. Homologous and heterologous antibody responses were analyzed by hemagglutination inhibition (HI), single radial hemolysis (SRH), and microneutralization (MN) assays 3 weeks after administration of the first vaccine dose and 3 weeks and 6 months after the second dose. Immunogenicity was assessed according to European licensure criteria for pandemic influenza vaccines. After two vaccine doses, all three European licensure criteria were met for adult and elderly subjects against the homologous vaccine strain, A/turkey/Turkey/1/2005, when analyzed by HI and SRH assays. Cross-reactive antibody responses were observed by HI and SRH analyses against the heterologous H5N1 strains, A/Indonesia/5/2005 and A/Vietnam/1194/2004, in adult and elderly subjects. Solicited local and systemic reactions were mostly mild to moderate in severity and occurred less frequently in the elderly than in adult vaccinees. In both adult and elderly subjects, MF59-adjuvanted vaccine containing 7.5 μg of A/Turkey strain influenza virus antigen was highly immunogenic, well tolerated, and able to elicit cross-clade, heterologous antibody responses against A/Indonesia and A/Vietnam strains 6 weeks after the first vaccination.

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Prabakaran, Mookkan, Fang He, Tao Meng, Selvaraj Madhan, Tan Yunrui, Qiang Jia et Jimmy Kwang. « Neutralizing Epitopes of Influenza Virus Hemagglutinin : Target for the Development of a Universal Vaccine against H5N1 Lineages ». Journal of Virology 84, n^o 22 (15 septembre 2010) : 11822–30. http://dx.doi.org/10.1128/jvi.00891-10.

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ABSTRACT The nature of influenza virus to randomly mutate and evolve into new types with diverse antigenic determinants is an important challenge in the control of influenza infection. Particularly, variations within the amino acid sequences of major neutralizing epitopes of influenza virus hemagglutinin (HA) hindered the development of universal vaccines against H5N1 lineages. Based on distribution analyses of the identified major neutralizing epitopes of hemagglutinin, we selected three vaccine strains that cover the entire variants in the neutralizing epitopes among the H5N1 lineages. HA proteins of selected vaccine strains were expressed on the baculovirus surface (BacHA), and the preclinical efficacy of the vaccine formulations was evaluated in a mouse model. The combination of three selected vaccine strains could effectively neutralize viruses from clades 1, 2.1, 2.2, 4, 7, and 8 of influenza H5N1 viruses. In contrast, a vaccine formulation containing only adjuvanted monovalent BacHA (mono-BacHA) or a single strain of inactivated whole viral vaccine was able to neutralize only clade 1 (homologous), clade 2.1, and clade 8.0 viruses. Also, the trivalent BacHA vaccine was able to protect 100% of the mice against challenge with three different clades (clade 1.0, clade 2.1, and clade 7.0) of H5N1 strains compared to mono-BacHA or inactivated whole viral vaccine. The present findings provide a rationale for the development of a universal vaccine against H5N1 lineages. Furthermore, baculoviruses displaying HA will serve as an ideal choice for a vaccine in prepandemic or pandemic situations and expedite vaccine technology without the requirement of high-level-biocontainment facilities or tedious protein purification processes.

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Steel, John, Anice C. Lowen, Lindomar Pena, Matthew Angel, Alicia Solórzano, Randy Albrecht, Daniel R. Perez, Adolfo García-Sastre et Peter Palese. « Live Attenuated Influenza Viruses Containing NS1 Truncations as Vaccine Candidates against H5N1 Highly Pathogenic Avian Influenza ». Journal of Virology 83, n^o 4 (10 décembre 2008) : 1742–53. http://dx.doi.org/10.1128/jvi.01920-08.

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ABSTRACT Due to the high mortality associated with recent, widely circulating strains of H5N1 influenza virus in poultry, the recurring introduction of H5N1 viruses from birds to humans, and the difficulties in H5N1 eradication by elimination of affected flocks, an effective vaccine against HPAI (highly pathogenic avian influenza) is highly desirable. Using reverse genetics, a set of experimental live attenuated vaccine strains based on recombinant H5N1 influenza virus A/Viet Nam/1203/04 was generated. Each virus was attenuated through expression of a hemagglutinin protein in which the polybasic cleavage site had been removed. Viruses were generated which possessed a full-length NS1 or a C-terminally truncated NS1 protein of 73, 99, or 126 amino acids. Viruses with each NS genotype were combined with a PB2 polymerase gene which carried either a lysine or a glutamic acid at position 627. We predicted that glutamic acid at position 627 of PB2 would attenuate the virus in mammalian hosts, thus increasing the safety of the vaccine. All recombinant viruses grew to high titers in 10-day-old embryonated chicken eggs but were attenuated in mammalian cell culture. Induction of high levels of beta interferon by all viruses possessing truncations in the NS1 protein was demonstrated by interferon bioassay. The viruses were each found to be highly attenuated in a mouse model. Vaccination with a single dose of any virus conferred complete protection from death upon challenge with a mouse lethal virus expressing H5N1 hemagglutinin and neuraminidase proteins. In a chicken model, vaccination with a single dose of a selected virus encoding the NS1 1-99 protein completely protected chickens from lethal challenge with homologous HPAI virus A/Viet Nam/1203/04 (H5N1) and provided a high level of protection from a heterologous virus, A/egret/Egypt/01/06 (H5N1). Thus, recombinant influenza A/Viet Nam/1203/04 viruses attenuated through the introduction of mutations in the hemagglutinin, NS1, and PB2 coding regions display characteristics desirable for live attenuated vaccines and hold potential as vaccine candidates in poultry as well as in mammalian hosts.

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Ruat, Caroline, Catherine Caillet, Alexandre Bidaut, James Simon et Albert D. M. E. Osterhaus. « Vaccination of Macaques with Adjuvanted Formalin-Inactivated Influenza A Virus (H5N1) Vaccines : Protection against H5N1 Challenge without Disease Enhancement ». Journal of Virology 82, n^o 5 (19 décembre 2007) : 2565–69. http://dx.doi.org/10.1128/jvi.01928-07.

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ABSTRACT We investigated the ability of adjuvanted, inactivated split-virion influenza A virus (H5N1) vaccines to protect against infection and demonstrated that the disease exacerbation phenomenon seen with adjuvanted formaldehyde-inactivated respiratory syncytial virus and measles virus investigational vaccines did not occur with these H5N1 vaccines. Macaques were vaccinated twice with or without an aluminum hydroxide or oil-in-water emulsion adjuvanted vaccine. Three months later, animals were challenged with homologous wild-type H5N1. No signs of vaccine-induced disease exacerbation were seen. With either adjuvant, vaccination induced functional and cross-reactive antibodies and protected the lungs and upper respiratory tract. Without an adjuvant, the vaccine provided partial protection. Best results were obtained with the emulsion adjuvant.

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Kamlangdee, Attapon, Brock Kingstad-Bakke et Jorge E. Osorio. « Mosaic H5 Hemagglutinin Provides Broad Humoral and Cellular Immune Responses against Influenza Viruses ». Journal of Virology 90, n^o 15 (18 mai 2016) : 6771–83. http://dx.doi.org/10.1128/jvi.00730-16.

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ABSTRACTThe most effective way to prevent influenza virus infection is via vaccination. However, the constant mutation of influenza viruses due to antigenic drift and shift compromises vaccine efficacy. This represents a major challenge to the development of a cross-protective vaccine that can protect against circulating viral antigenic diversity. Using the modified vaccinia Ankara (MVA) virus, we had previously generated a recombinant vaccine against highly pathogenic avian influenza virus (H5N1) based on anin silicomosaic approach. This MVA-H5M construct protected mice against multiple clades of H5N1 and H1N1 viruses. We have now further characterized the immune responses using immunodepletion of T cells and passive serum transfer, and these studies indicate that antibodies are the main contributors in homosubtypic protection (H5N1 clades). Compared to a MVA construct expressing hemagglutinin (HA) from influenza virus A/VN/1203/04 (MVA-HA), the MVA-H5M vaccine markedly increased and broadened B cell and T cell responses against H5N1 virus. The MVA-H5M also provided effective protection with no morbidity against H5N1 challenge, whereas MVA-HA-vaccinated mice showed clinical signs and experienced significant weight loss. In addition, MVA-H5M induced CD8+T cell responses that play a major role in heterosubtypic protection (H1N1). Finally, expression of the H5M gene as either a DNA vaccine or a subunit protein protected mice against H5N1 challenge, indicating the effectiveness of the mosaic sequence without viral vectors for the development of a universal influenza vaccine.IMPORTANCEInfluenza viruses infect up to one billion people around the globe each year and are responsible for 300,000 to 500,000 deaths annually. Vaccines are still the main intervention to prevent infection, but they fail to provide effective protection against heterologous strains of viruses. We developed broadly reactive H5N1 vaccine based on anin silicomosaic approach and previously demonstrated that modified vaccinia Ankara expressing an H5 mosaic hemagglutinin prevented infection with multiple clades of H5N1 and limited severe disease after H1N1 infection. Further characterization revealed that antibody responses and T cells are main contributors to protection against H5N1 and H1N1 viruses, respectively. The vaccine also broadens both T cell and B cell responses compared to native H5 vaccine from influenza virus A/Vietnam/1203/04. Finally, delivering the H5 mosaic as a DNA vaccine or as a purified protein demonstrated effective protection similar to the viral vector approach.

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Hoang, Hang Thi Thu, Chi Hung Nguyen, Ngan Thi Thuy Nguyen, An Dang Pham, Hang Thi Thu Nguyen, Thanh Hoa Le, Hanh Xuan Tran, Ha Hoang Chu et Nam Trung Nguyen. « Immunization with the H5N1 Recombinant Vaccine Candidate Induces High Protection in Chickens against Vietnamese Highly Pathogenic Avian Influenza Virus Strains ». Vaccines 8, n^o 2 (2 avril 2020) : 159. http://dx.doi.org/10.3390/vaccines8020159.

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Vietnam is one of the countries most affected worldwide by the highly pathogenic avian influenza (HPAI) virus, which caused enormous economic loss and posed threats to public health. Over nearly two decades, with the antigenic changes in the diversified H5Ny viruses, the limited protective efficacy of the available vaccines was encountered. Therefore, it is necessary to approach a technology platform for the country to accelerate vaccine production that enables quick response to new influenza subtypes. This study utilized a powerful reverse genetics technique to successfully generate a recombinant H5N1 vaccine strain (designated as IBT-RG02) containing two surface proteins (haemagglutinin (HA) and neuraminidase (NA)) from the HPAI H5N1 (A/duck/Vietnam/HT2/2014(H5N1)) of the dominant clade 2.3.2.1c in Vietnam during 2012–2014. Importantly, the IBT-RG02 vaccine candidate has elicited high antibody titres in chickens (geometric mean titre (GMT) of 6.42 and 6.92, log2 on day 14 and day 28 p.i., respectively). To test the efficacy, immunized chickens were challenged with the circulating virulent strains. As results, there was a high protection rate of 91.6% chickens against the virulent A/DK/VN/Bacninh/NCVD-17A384/2017 of the same clade and a cross-protection of 83.3% against A/duck/TG/NAVET(3)/2013 virus of clade 1.1. Our promising results showed that we can independently master the reverse genetics technology for generation of highly immunogenic vaccine candidates, and henceforth, it is a timely manner to reformulate avian influenza virus vaccines against variable H5 clade HPAI viruses in Vietnam.

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Kiseleva, Irina, Natalie Larionova et Larisa Rudenko. « Live Attenuated Reassortant Vaccines Based on A/Leningrad/134/17/57 Master Donor Virus Against H5 Avian Influenza ». Open Microbiology Journal 11, n^o 1 (30 novembre 2017) : 316–29. http://dx.doi.org/10.2174/1874285801711010316.

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Background:The H5N1 avian influenza was first recognized in humans in Hong Kong 20 years ago. Current enzootic spread of highly pathogenic H5N1 virus among wild and domestic poultry and a number of severe human respiratory diseases caused by this pathogen have stimulated necessity of development of potentially pandemic influenza vaccines.Discussion:In the past few years, significant research was conducted on how to prevent H5N1 influenza. Live, attenuated cold–adapted reassortant influenza vaccine (LAIV) is considered as one of the most promising candidates for pandemic and prepandemic vaccines. LAIV has proven to be safe and efficacious; pandemic LAIV might be more effective than inactivated vaccine in providing broader immune response.Conclusion:This review covers development of LAIVs against potential avian “pandemic” H5N1 subtype based on cold–adapted A/Leningrad/134/17/57 (H2N2) master donor virus backbone, and their preclinical and clinical studies.

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Vajo, Zoltan, John Wood, Lajos Kosa, Istvan Szilvasy, Gyorgy Paragh, Zsuzsanna Pauliny, Kálmán Bartha, Ildiko Visontay, Agnes Kis et Istvan Jankovics. « A Single-Dose Influenza A (H5N1) Vaccine Safe and Immunogenic in Adult and Elderly Patients : an Approach to Pandemic Vaccine Development ». Journal of Virology 84, n^o 3 (11 novembre 2009) : 1237–42. http://dx.doi.org/10.1128/jvi.01894-09.

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ABSTRACT With the ongoing pandemic of influenza A (H1N1) virus infection and the threat of high fatality rates for recent human cases of infection with highly pathogenic H5N1 strains, there has been considerable interest in developing pandemic vaccines. Here we report a randomized multicenter dose-finding clinical trial of a whole-virion, inactivated, adjuvanted H5N1 vaccine in adult and elderly volunteers. Four hundred eighty patients were randomly assigned to receive one or two doses of 3.5 μg of the vaccine or one dose of 6 or 12 μg. The subjects were monitored for safety analysis, and serum samples were obtained to assess immunogenicity by hemagglutination inhibition and microneutralization tests. The subjects developed antibody responses against the influenza A (H5N1) virus. Single doses of ≥6 μg fulfilled EU and U.S. licensing criteria for interpandemic and pandemic influenza vaccines. Except for occasional injection site pain, malaise, and fever, no adverse events were observed. We found that the present vaccine is safe and immunogenic in healthy adult and elderly subjects and requires low doses and, unlike any other H5N1 vaccines, only one injection to trigger immune responses which comply with licensing criteria. A vaccine using the same methods as those described in this report, but based on a wild-type swine-origin 2009 (H1N1) influenza A virus isolate from the United States (supplied by the CDC), has been developed and is currently being tested by our group.

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Tompkins, Stephen, Alaina Mooney, Zhou Li, Jon Gabbard, Daniel Dlugolenski, Scott Johnson, Ralph Tripp et Biao He. « Vaccination with recombinant PIV5 expressing influenza neuraminidase provides protection against homologous and heterologous influenza virus infection (P4291) ». Journal of Immunology 190, n^o 1_Supplement (1 mai 2013) : 123.9. http://dx.doi.org/10.4049/jimmunol.190.supp.123.9.

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Abstract Vaccination is considered the most effective measure for controlling influenza virus infection, however current vaccination methods are inadequate. Virus-vectored vaccines offer an appealing alternative. Parainfluenza virus 5 (PIV5), a non-segmented, negative-stranded RNA virus (NNSV) in the family Paramyxoviridae is an appealing vector candidate as it has a stable genome without a DNA phase in its life cycle, is readily grown to high titers in approved vaccine cell lines, and infects many mammals without causing disease. Neuraminidase (NA), a glycoprotein found on the surface of influenza A virus as well as virus-infected cells is more conserved than the hemagglutinin surface glycoprotein, the primary antigen in current influenza vaccines. This increases the likelihood of achieving broad protection if used as a vaccine antigen. We show that vaccination with PIV5 expressing the NA from H5N1 highly pathogenic avian influenza (HPAI; rPIV5-N1 (H5N1)) or pandemic H1N1 (rPIV5-N1 (H1N1)) primes robust NA-specific antibody and T cell responses and confers complete protection against homologous (NA-matched) influenza virus challenge. Moreover, immunization also confers significant cross-protection against challenge with heterologous influenza virus within the same NA type. These results suggest that NA can be an effective vaccine antigen and protect against even a stringent challenge, such as with H5N1 HPAI virus, making it an appealing candidate pandemic influenza vaccine.

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Krauss, Scott, David E. Stallknecht, Richard D. Slemons, Andrew S. Bowman, Rebecca L. Poulson, Jacqueline M. Nolting, James P. Knowles et Robert G. Webster. « The enigma of the apparent disappearance of Eurasian highly pathogenic H5 clade 2.3.4.4 influenza A viruses in North American waterfowl ». Proceedings of the National Academy of Sciences 113, n^o 32 (25 juillet 2016) : 9033–38. http://dx.doi.org/10.1073/pnas.1608853113.

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One of the major unresolved questions in influenza A virus (IAV) ecology is exemplified by the apparent disappearance of highly pathogenic (HP) H5N1, H5N2, and H5N8 (H5Nx) viruses containing the Eurasian hemagglutinin 2.3.4.4 clade from wild bird populations in North America. The introduction of Eurasian lineage HP H5 clade 2.3.4.4 H5N8 IAV and subsequent reassortment with low-pathogenic H?N2 and H?N1 North American wild bird-origin IAVs in late 2014 resulted in widespread HP H5Nx IAV infections and outbreaks in poultry and wild birds across two-thirds of North America starting in November 2014 and continuing through June 2015. Although the stamping out strategies adopted by the poultry industry and animal health authorities in Canada and the United States—which included culling, quarantining, increased biosecurity, and abstention from vaccine use—were successful in eradicating the HP H5Nx viruses from poultry, these activities do not explain the apparent disappearance of these viruses from migratory waterfowl. Here we examine current and historical aquatic bird IAV surveillance and outbreaks of HP H5Nx in poultry in the United States and Canada, providing additional evidence of unresolved mechanisms that restrict the emergence and perpetuation of HP avian influenza viruses in these natural reservoirs.

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Hampson, Alan W. « Vaccines for Pandemic Influenza. The History of our Current Vaccines, their Limitations and the Requirements to Deal with a Pandemic Threat ». Annals of the Academy of Medicine, Singapore 37, n^o 6 (15 juin 2008) : 510–17. http://dx.doi.org/10.47102/annals-acadmedsg.v37n6p510.

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Fears of a potential pandemic due to A(H5N1) viruses have focussed new attention on our current vaccines, their shortcomings, and concerns regarding global vaccine supply in a pandemic. The bulk of current vaccines are inactivated split virus vaccines produced from egggrown virus and have only modest improvements compared with those first introduced over 60 years ago. Splitting, which was introduced some years ago to reduce reactogenicity, also reduces the immunogenicity of vaccines in immunologically naïve recipients. The A(H5N1) viruses have been found poorly immunogenic and present other challenges for vaccine producers which further exacerbate an already limited global production capacity. There have been some recent improvements in vaccine production methods and improvements to immunogenicity by the development of new adjuvants, however, these still fall short of providing timely supplies of vaccine for all in the face of a pandemic. New approaches to influenza vaccines which might fulfil the demands of a pandemic situation are under evaluation, however, these remain some distance from clinical reality and face significant regulatory hurdles. Key words: Adjuvant, Antigen, Cell-culture, Immune response, Immunogenicity, Influenza A(H5N1), Split vaccine

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Fazekas, György, Rita Martosne-Mendi, Istvan Jankovics, Istvan Szilvasy et Zoltan Vajo. « Cross-Reactive Immunity to Clade 2 Strains of Influenza Virus A Subtype H5N1 Induced in Adults and Elderly Patients by Fluval, a Prototype Pandemic Influenza Virus Vaccine Derived by Reverse Genetics, Formulated with a Phosphate Adjuvant, and Directed to Clade 1 Strains ». Clinical and Vaccine Immunology 16, n^o 4 (19 novembre 2008) : 437–43. http://dx.doi.org/10.1128/cvi.00327-08.

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ABSTRACT High fatality rates and multiple cases of transmission of avian H5N1 influenza viruses to humans illustrate the urgent need for an efficacious, cross-protective vaccine against H5N1 strains. Extensive genetic characterization of H5N1 strains has elucidated the natural evolutionary relationship of these strains, linking groups known as clades to a common ancestor. Although the clades and subclades probably differ sufficiently in their antigenic structure to warrant the preparation of different vaccines, there is some evidence that cross-reactive immunity can be afforded. We aimed to assess the immunogenicity of a clade 1 H5N1 (NIBRG-14) whole-virus vaccine with an aluminum phosphate adjuvant and to determine whether it can induce cross-reactive immunity against antigenically drifted clade 2 H5N1 strains, both those derived by reverse genetics and wild-type isolates. A total of 88 (44 adult and 44 elderly) subjects, who received one dose (6 μg) of the vaccine, were studied. As judged by U.S. and European licensing criteria based on hemagglutination inhibition, the subjects developed cross-reactive immunity against all studied H5N1 strains belonging to a clade different from that of the strain utilized to produce the vaccine. Our findings highlight the importance of stockpiling, since cross-immune reactions induced by prepandemic vaccines will likely reduce morbidity and mortality in case of a pandemic.

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Lopez, Pio, Yolanda Caicedo, Alexandra Sierra, Sandrine Tilman, Ralf Clemens et Angelika Banzhoff. « Combined Administration of MF59-Adjuvanted A/H5N1 Prepandemic and Seasonal Influenza Vaccines : Long-Term Antibody Persistence and Robust Booster Responses 1 Year after a One-Dose Priming Schedule ». Clinical and Vaccine Immunology 20, n^o 5 (27 mars 2013) : 753–58. http://dx.doi.org/10.1128/cvi.00626-12.

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ABSTRACTHaving previously demonstrated the feasibility of administering A/H5N1 and seasonal influenza vaccine antigens in an MF59-adjuvanted tetravalent formulation, we now report on long-term antibody persistence and responses to a booster dose of a combined seasonal-pandemic, tetravalent influenza vaccine in adults. The primary objective was the evaluation of responses to a booster dose of tetravalent influenza vaccine containing seasonal (A/H1N1, A/H3N2, and B) and avian (A/H5N1, clade 2) influenza virus strains administered to 265 healthy 18- to 40-year-old volunteers 1 year after priming with one or two clade 1 A/H5N1 doses. Secondary objectives were assessment of reactogenicity, safety, and antibody persistence 1 year after priming with a combined seasonal-pandemic, tetravalent vaccine. Responses to seasonal strains met all European licensure criteria; seroprotection rates were 94 to 100%, 100%, and 61 to 90% for A/H1N1, A/H3N2, and B strains, respectively. Anamnestic responses were observed against homologous and heterologous A/H5N1 strains whether priming with one or two A/H5N1 doses, with a monovalent A/H5N1 vaccine, or with a tetravalent vaccine. A single dose of MF59-adjuvanted A/H5N1 vaccine given alone or as part of a fixed combination with a seasonal influenza vaccine was sufficient to prime adult subjects, resulting in robust antigen-specific and cross-reactive antibody responses to heterologous booster immunization 1 year later. These data support the feasibility of incorporating prepandemic priming into seasonal influenza vaccination programs. (This study has been registered at clinicaltrials.gov under registration no. NCT00481065.)

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Song, Haichen, Gloria Ramirez Nieto et Daniel R. Perez. « A New Generation of Modified Live-Attenuated Avian Influenza Viruses Using a Two-Strategy Combination as Potential Vaccine Candidates ». Journal of Virology 81, n^o 17 (27 juin 2007) : 9238–48. http://dx.doi.org/10.1128/jvi.00893-07.

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ABSTRACT In light of the recurrent outbreaks of low pathogenic avian influenza (LPAI) and highly pathogenic avian influenza (HPAI), there is a pressing need for the development of vaccines that allow rapid mass vaccination. In this study, we introduced by reverse genetics temperature-sensitive mutations in the PB1 and PB2 genes of an avian influenza virus, A/Guinea Fowl/Hong Kong/WF10/99 (H9N2) (WF10). Further genetic modifications were introduced into the PB1 gene to enhance the attenuated (att) phenotype of the virus in vivo. Using the att WF10 as a backbone, we substituted neuraminidase (NA) for hemagglutinin (HA) for vaccine purposes. In chickens, a vaccination scheme consisting of a single dose of an att H7N2 vaccine virus at 2 weeks of age and subsequent challenge with the wild-type H7N2 LPAI virus resulted in complete protection. We further extended our vaccination strategy against the HPAI H5N1. In this case, we reconstituted an att H5N1 vaccine virus, whose HA and NA genes were derived from an Asian H5N1 virus. A single-dose immunization in ovo with the att H5N1 vaccine virus in 18-day-old chicken embryos resulted in more than 60% protection for 4-week-old chickens and 100% protection for 9- to 12-week-old chickens. Boosting at 2 weeks posthatching provided 100% protection against challenge with the HPAI H5N1 virus for chickens as young as 4 weeks old, with undetectable virus shedding postchallenge. Our results highlight the potential of live att avian influenza vaccines for mass vaccination in poultry.

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Middleton, Deborah, Steven Rockman, Martin Pearse, Ian Barr, Sue Lowther, Jessica Klippel, David Ryan et Lorena Brown. « Evaluation of Vaccines for H5N1 Influenza Virus in Ferrets Reveals the Potential for Protective Single-Shot Immunization ». Journal of Virology 83, n^o 15 (20 mai 2009) : 7770–78. http://dx.doi.org/10.1128/jvi.00241-09.

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ABSTRACT As part of influenza pandemic preparedness, policy decisions need to be made about how best to utilize vaccines once they are manufactured. Since H5N1 avian influenza virus has the potential to initiate the next human pandemic, isolates of this subtype have been used for the production and testing of prepandemic vaccines. Clinical trials of such vaccines indicate that two injections of preparations containing adjuvant will be required to induce protective immunity. However, this is a working assumption based on classical serological measures only. Examined here are the dose of viral hemagglutinin (HA) and the number of inoculations required for two different H5N1 vaccines to achieve protection in ferrets after lethal H5N1 challenge. Ferrets inoculated twice with 30 μg of A/Vietnam/1194/2004 HA vaccine with AlPO4, or with doses as low as 3.8 μg of HA with Iscomatrix (ISCOMATRIX, referred to as Iscomatrix herein, is a registered trademark of CSL Limited) adjuvant, were completely protected against death and disease after H5N1 challenge, and the protection lasted at least 15 months. Cross-clade protection was also observed with both vaccines. Significantly, complete protection against death could be achieved with only a single inoculation of H5N1 vaccine containing as little as 15 μg of HA with AlPO4 or 3.8 μg of HA with Iscomatrix adjuvant. Ferrets vaccinated with the single-injection Iscomatrix vaccines showed fewer clinical manifestations of infection than those given AlPO4 vaccines and remained highly active. Our data provide the first indication that in the event of a future influenza pandemic, effective mass vaccination may be achievable with a low-dose “single-shot” vaccine and provide not only increased survival but also significant reduction in disease severity.

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Vergara-Alert, Júlia, Hugo Fernández-Bellon, Núria Busquets, Gabriel Alcántara, María Delclaux, Bienvenido Pizarro, Celia Sánchez, Azucena Sánchez, Natàlia Majó et Ayub Darji. « Comprehensive Serological Analysis of Two Successive Heterologous Vaccines against H5N1 Avian Influenza Virus in Exotic Birds in Zoos ». Clinical and Vaccine Immunology 18, n^o 5 (23 mars 2011) : 697–706. http://dx.doi.org/10.1128/cvi.00013-11.

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ABSTRACTIn 2005, European Commission directive 2005/744/EC allowed controlled vaccination against avian influenza (AI) virus of valuable avian species housed in zoos. In 2006, 15 Spanish zoos and wildlife centers began a vaccination program with a commercial inactivated H5N9 vaccine. Between November 2007 and May 2008, birds from 10 of these centers were vaccinated again with a commercial inactivated H5N3 vaccine. During these campaigns, pre- and postvaccination samples from different bird orders were taken to study the response against AI virus H5 vaccines. Sera prior to vaccinations with both vaccines were examined for the presence of total antibodies against influenza A nucleoprotein (NP) by a commercial competitive enzyme-linked immunosorbent assay (cELISA). Humoral responses to vaccination were evaluated using a hemagglutination inhibition (HI) assay. In some taxonomic orders, both vaccines elicited comparatively high titers of HI antibodies against H5. Interestingly, some orders, such as Psittaciformes, which did not develop HI antibodies to either vaccine formulation when used alone, triggered notable HI antibody production, albeit in low HI titers, when primed with H5N9 and during subsequent boosting with the H5N3 vaccine. Vaccination with successive heterologous vaccines may represent the best alternative to widely protect valuable and/or endangered bird species against highly pathogenic AI virus infection.

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Haredy, Ahmad M., Nobuyuki Takenaka, Hiroshi Yamada, Yoshihiro Sakoda, Masatoshi Okamatsu, Naoki Yamamoto, Takeshi Omasa et al. « An MDCK Cell Culture-Derived Formalin-Inactivated Influenza Virus Whole-Virion Vaccine from an Influenza Virus Library Confers Cross-Protective Immunity by Intranasal Administration in Mice ». Clinical and Vaccine Immunology 20, n^o 7 (1 mai 2013) : 998–1007. http://dx.doi.org/10.1128/cvi.00024-13.

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ABSTRACTIt is currently impossible to predict the next pandemic influenza virus strain. We have thus established a library of influenza viruses of all hemagglutinin and neuraminidase subtypes and their genes. In this article, we examine the applicability of a rapid production model for the preparation of vaccines against emerging pandemic influenza viruses. This procedure utilizes the influenza virus library, cell culture-based vaccine production, and intranasal administration to induce a cross-protective immune response. First, an influenza virus reassortant from the library, A/duck/Hokkaido/Vac-3/2007 (H5N1), was passaged 22 times (P22) in Madin-Darby canine kidney (MDCK) cells. The P22 virus had a titer of >2 ×108PFU/ml, which was 40 times that of the original strain, with 4 point mutations, which altered amino acids in the deduced protein sequences encoded by the PB2 and PA genes. We then produced a formalin-inactivated whole-virion vaccine from the MDCK cell-cultured A/duck/Hokkaido/Vac-3/2007 (H5N1) P22 virus. Intranasal immunization of mice with this vaccine protected them against challenges with lethal influenza viruses of homologous and heterologous subtypes. We further demonstrated that intranasal immunization with the vaccine induced cross-reactive neutralizing antibody responses against the homotypic H5N1 influenza virus and its antigenic variants and cross-reactive cell-mediated immune responses to the homologous virus, its variants within a subtype, and even an influenza virus of a different subtype. These results indicate that a rapid model for emergency vaccine production may be effective for producing the next generation of pandemic influenza virus vaccines.

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Giles, Brendan M., Stephanie J. Bissel, Dilhari R. DeAlmeida, Clayton A. Wiley et Ted M. Ross. « Antibody Breadth and Protective Efficacy Are Increased by Vaccination with Computationally Optimized Hemagglutinin but Not with Polyvalent Hemagglutinin-Based H5N1 Virus-Like Particle Vaccines ». Clinical and Vaccine Immunology 19, n^o 2 (21 décembre 2011) : 128–39. http://dx.doi.org/10.1128/cvi.05533-11.

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ABSTRACTOne of the challenges for developing an H5N1 influenza vaccine is the diversity of antigenically distinct isolates within this subtype. Previously, our group described a novel hemagglutinin (HA) derived from a methodology termed computationally optimized broadly reactive antigen (COBRA). This COBRA HA, when used as an immunogen, elicits a broad antibody response against H5N1 isolates from different clades. In this report, the immune responses elicited by the COBRA HA virus-like particle (VLP) vaccine were compared to responses elicited by a mixture of VLPs expressing representative HA molecules from clade 2.1, 2.2, and 2.3 primary H5N1 isolates (polyvalent). The COBRA HA VLP vaccine elicited higher-titer antibodies to a panel of H5N1 HA proteins than did the other VLPs. Both COBRA and polyvalent vaccines protected vaccinated mice and ferrets from experimental infection with highly lethal H5N1 influenza viruses, but COBRA-vaccinated animals had decreased viral replication, less inflammation in the lungs of mice, and reduced virus recovery in ferret nasal washes. Both vaccines had similar cellular responses postchallenge, indicating that higher-titer serum antibodies likely restrict the duration of viral replication. Furthermore, passively transferred immune serum from the COBRA HA VLP-vaccinated mice protected recipient animals more efficiently than immune serum from polyvalent-vaccinated mice. This is the first report comparing these two vaccine strategies. The single COBRA HA antigen elicited a broader antibody response and reduced morbidity and viral titers more effectively than a polyvalent mixture of primary H5N1 HA antigens.

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van der Velden, Maikel V. W., Alexander Geisberger, Thomas Dvorak, Daniel Portsmouth, Richard Fritz, Brian A. Crowe, Wolfgang Herr et al. « Safety and Immunogenicity of a Vero Cell Culture-Derived Whole-Virus H5N1 Influenza Vaccine in Chronically Ill and Immunocompromised Patients ». Clinical and Vaccine Immunology 21, n^o 6 (16 avril 2014) : 867–76. http://dx.doi.org/10.1128/cvi.00065-14.

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ABSTRACTThe development of vaccines against H5N1 influenza A viruses is a cornerstone of pandemic preparedness. Clinical trials of H5N1 vaccines have been undertaken in healthy subjects, but studies in risk groups have been lacking. In this study, the immunogenicity and safety of a nonadjuvanted cell culture-derived whole-virus H5N1 vaccine were assessed in chronically ill and immunocompromised adults. Subjects received two priming immunizations with a clade 1 A/Vietnam H5N1 influenza vaccine, and a subset also received a booster immunization with a clade 2.1 A/Indonesia H5N1 vaccine 12 to 24 months later. The antibody responses in the two populations were assessed by virus neutralization and single radial hemolysis assays. The T-cell responses in a subset of immunocompromised patients were assessed by enzyme-linked immunosorbent spot assay (ELISPOT). The priming and the booster vaccinations were safe and well tolerated in the two risk populations, and adverse reactions were predominantly mild and transient. The priming immunizations induced neutralizing antibody titers of ≥1:20 against the A/Vietnam strain in 64.2% of the chronically ill and 41.5% of the immunocompromised subjects. After the booster vaccination, neutralizing antibody titers of ≥1:20 against the A/Vietnam and A/Indonesia strains were achieved in 77.5% and 70.8%, respectively, of chronically ill subjects and in 71.6% and 67.5%, respectively, of immunocompromised subjects. The T-cell responses against the two H5N1 strains increased significantly over the baseline values. Substantial heterosubtypic T-cell responses were elicited against the 2009 pandemic H1N1 virus and seasonal A(H1N1), A(H3N2), and B subtypes. There was a significant correlation between T-cell responses and neutralizing antibody titers. These data indicate that nonadjuvanted whole-virus cell culture-derived H5N1 influenza vaccines are suitable for immunizing chronically ill and immunocompromised populations. (This study is registered at ClinicalTrials.gov under registration no. NCT00711295.)

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Murakami, Shin, Taisuke Horimoto, Le Quynh Mai, Chairul A. Nidom, Hualan Chen, Yukiko Muramoto, Shinya Yamada et al. « Growth Determinants for H5N1 Influenza Vaccine Seed Viruses in MDCK Cells ». Journal of Virology 82, n^o 21 (3 septembre 2008) : 10502–9. http://dx.doi.org/10.1128/jvi.00970-08.

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ABSTRACT H5N1 influenza A viruses are exacting a growing human toll, with more than 240 fatal cases to date. In the event of an influenza pandemic caused by these viruses, embryonated chicken eggs, which are the approved substrate for human inactivated-vaccine production, will likely be in short supply because chickens will be killed by these viruses or culled to limit the worldwide spread of the infection. The Madin-Darby canine kidney (MDCK) cell line is a promising alternative candidate substrate because it supports efficient growth of influenza viruses compared to other cell lines. Here, we addressed the molecular determinants for growth of an H5N1 vaccine seed virus in MDCK cells, revealing the critical responsibility of the Tyr residue at position 360 of PB2, the considerable requirement for functional balance between hemagglutinin (HA) and neuraminidase (NA), and the partial responsibility of the Glu residue at position 55 of NS1. Based on these findings, we produced a PR8/H5N1 reassortant, optimized for this cell line, that derives all of its genes for its internal proteins from the PR8(UW) strain except for the NS gene, which derives from the PR8(Cambridge) strain; its N1 NA gene, which has a long stalk and derives from an early H5N1 strain; and its HA gene, which has an avirulent-type cleavage site sequence and is derived from a circulating H5N1 virus. Our findings demonstrate the importance and feasibility of a cell culture-based approach to producing seed viruses for inactivated H5N1 vaccines that grow robustly and in a timely, cost-efficient manner as an alternative to egg-based vaccine production.

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&NA;. « Adjuvant boosts H5N1 influenza vaccine immunogenicity ». Inpharma Weekly &NA;, n^o 1602 (août 2007) : 8. http://dx.doi.org/10.2165/00128413-200716020-00019.

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Clegg, Christopher H., Joseph A. Rininger et Susan L. Baldwin. « Clinical vaccine development for H5N1 influenza ». Expert Review of Vaccines 12, n^o 7 (juillet 2013) : 767–77. http://dx.doi.org/10.1586/14760584.2013.811178.

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Prabakaran, Mookkan, Selvaraj Madhan, Nayana Prabhu, Jia Qiang et Jimmy Kwang. « Gastrointestinal Delivery of Baculovirus Displaying Influenza Virus Hemagglutinin Protects Mice against Heterologous H5N1 Infection ». Journal of Virology 84, n^o 7 (13 janvier 2010) : 3201–9. http://dx.doi.org/10.1128/jvi.02175-09.

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ABSTRACT The recent outbreaks of influenza A H5N1 virus in birds and humans have necessitated the development of potent H5N1 vaccines. In this study, we evaluated the protective potential of an immediate-early promoter-based baculovirus displaying hemagglutinin (BacHA) against highly pathogenic avian influenza (HPAI) H5N1 virus infection in a mouse model. Gastrointestinal delivery of BacHA significantly enhanced the systemic immune response in terms of HA-specific serum IgG and hemagglutination inhibition (HI) titers. In addition, BacHA vaccine was able to significantly enhance the mucosal IgA level. The inclusion of recombinant cholera toxin B subunit as a mucosal adjuvant along with BacHA vaccine did not influence either the systemic or mucosal immunity. Interestingly, an inactivated form of BacHA was able to induce only a negligible level of immune responses compared to its live counterpart. Microneutralization assay also indicated that live BacHA vaccine was able to induce strong cross-clade neutralization against heterologous H5N1 strains (clade 1.0, clade 2.1, and clade 8.0) compared to the inactivated BacHA. Viral challenge studies showed that live BacHA was able to provide 100% protection against 5 50% mouse lethal doses (MLD50) of homologous (clade 2.1) and heterologous (clade 1) H5N1. Moreover, histopathological examinations revealed that mice vaccinated with live BacHA had only minimal bronchitis in lungs and regained their body weight more rapidly postchallenge. Furthermore, immunohistochemistry results demonstrated that the live BacHA was able to transduce and express HA in the intestinal epithelial cells in vitro and in vivo. We have demonstrated that recombinant baculovirus with a white spot syndrome virus (WSSV) immediate-early promoter 1 (ie1) acted as a vector as well as a protein vaccine and will enable the rapid production of prepandemic and pandemic vaccines without any biosafety concerns.

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Lau, Yuk-Fai, Lay-Hoon Tang, Amber W. McCall, Eng-Eong Ooi et Kanta Subbarao. « An Adjuvant for the Induction of Potent, Protective Humoral Responses to an H5N1 Influenza Virus Vaccine with Antigen-Sparing Effect in Mice ». Journal of Virology 84, n^o 17 (10 juin 2010) : 8639–49. http://dx.doi.org/10.1128/jvi.00596-10.

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ABSTRACT Intramuscular administration of inactivated influenza virus vaccine is the main vaccine platform used for the prevention of seasonal influenza virus infection. In clinical trials, inactivated H5N1 vaccines have been shown to be safe and capable of eliciting immune correlates of protection. However, the H5N1 vaccines are poorly immunogenic compared to seasonal influenza virus vaccines. Needle-free vaccination would be more efficient and economical in a pandemic, and the development of an effective and safe mucosal adjuvant will be an important milestone. A stabilized chemical analog of double-stranded RNA, PIKA, was previously reported to be a potent mucosal adjuvant in a murine model. While PIKA stimulates dendritic cells in vitro, little was known about its receptor and adjuvanting mechanism in vivo. In this study, we demonstrated that the immunostimulatory effect of PIKA resulted in an increased number of mature antigen-presenting cells, with the induction of proinflammatory cytokines at the inoculation site. In addition, coadministration of PIKA with a poorly immunogenic H5N1 subunit vaccine led to antigen sparing and quantitative and qualitative improvements of the immune responses over those achieved with an unadjuvanted vaccine in mice. The adjuvanted vaccine provided protection against lethal challenge with homologous and heterologous H5N1 wild-type viruses. Mice lacking functional TLR3 showed diminished cytokine production with PIKA stimulation, diminished antibody responses, and reduced protective efficacy against wild-type virus challenge following vaccination. These data suggest that TLR3 is important for the optimal performance of PIKA as an adjuvant. With its good safety profile and antigen-sparing effect, PIKA could be an attractive adjuvant for use in future pandemics.

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Shelton, Holly, Kim L. Roberts, Eleonora Molesti, Nigel Temperton et Wendy S. Barclay. « Mutations in haemagglutinin that affect receptor binding and pH stability increase replication of a PR8 influenza virus with H5 HA in the upper respiratory tract of ferrets and may contribute to transmissibility ». Journal of General Virology 94, n^o 6 (1 juin 2013) : 1220–29. http://dx.doi.org/10.1099/vir.0.050526-0.

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The H5N1 influenza A viruses have circulated widely in the avian population for 10 years with only sporadic infection of humans observed and no sustained human to human transmission. Vaccination against potential pandemic strains is one strategy in planning for future influenza pandemics; however, the success of live attenuated vaccines for H5N1 has been limited, due to poor replication in the human upper respiratory tract (URT). Mutations that increase the ability of H5N1 viruses to replicate in the URT will aid immunogenicity of these vaccines and provide information about humanizing adaptations in H5N1 strains that may signal transmissibility. As well as mediating receptor interactions, the haemagglutinin (HA) protein of influenza facilitates fusion of the viral membrane and genome entry into the host cell; this process is pH dependent. We have shown in this study that the pH at which a panel of avian influenza HA proteins, including H5, mediate fusion is higher than that for human influenza HA proteins, and that mutations in the H5 HA can reduce the pH of fusion. Coupled with receptor switching mutations, increasing the pH stability of the H5 HA resulted in increased viral shedding of H5N1 from the nasal cavity of ferrets and contact transmission to a co-housed animal. Ferret serum antibodies induced by infection with any of the mutated H5 HA viruses neutralized HA pseudotyped lentiviruses bearing homologous or heterologous H5 HAs, suggesting that this strategy to increase nasal replication of a vaccine virus would not compromise vaccine efficacy.

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Zhang, Zhegang, Zheng Jiang, Tao Deng, Jiayou Zhang, Bo Liu, Jing Liu, Ran Qiu et al. « Preclinical immunogenicity assessment of a cell-based inactivated whole-virion H5N1 influenza vaccine ». Open Life Sciences 17, n^o 1 (1 janvier 2022) : 1282–95. http://dx.doi.org/10.1515/biol-2022-0478.

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Abstract In influenza vaccine development, Madin–Darby canine kidney (MDCK) cells provide multiple advantages, including large-scale production and egg independence. Several cell-based influenza vaccines have been approved worldwide. We cultured H5N1 virus in a serum-free MDCK cell suspension. The harvested virus was manufactured into vaccines after inactivation and purification. The vaccine effectiveness was assessed in the Wuhan Institute of Biological Products BSL2 facility. The pre- and postvaccination mouse serum titers were determined using the microneutralization and hemagglutination inhibition tests. The immunological responses induced by vaccine were investigated using immunological cell classification, cytokine expression quantification, and immunoglobulin G (IgG) subtype classification. The protective effect of the vaccine in mice was evaluated using challenge test. Antibodies against H5N1 in rats lasted up to 8 months after the first dose. Compared with those of the placebo group, the serum titer of vaccinated mice increased significantly, Th1 and Th2 cells were activated, and CD8+ T cells were activated in two dose groups. Furthermore, the challenge test showed that vaccination reduced the clinical symptoms and virus titer in the lungs of mice after challenge, indicating a superior immunological response. Notably, early after vaccination, considerably increased interferon-inducible protein-10 (IP-10) levels were found, indicating improved vaccine-induced innate immunity. However, IP-10 is an adverse event marker, which is a cause for concern. Overall, in the case of an outbreak, the whole-virion H5N1 vaccine should provide protection.

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Vahlenkamp, Thomas W., Timm C. Harder, Matthias Giese, Fengsheng Lin, Jens P. Teifke, Robert Klopfleisch, Ralf Hoffmann, Ian Tarpey, Martin Beer et Thomas C. Mettenleiter. « Protection of cats against lethal influenza H5N1 challenge infection ». Journal of General Virology 89, n^o 4 (1 avril 2008) : 968–74. http://dx.doi.org/10.1099/vir.0.83552-0.

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Highly pathogenic avian influenza virus (HPAIV) H5N1 of Asian origin continues to circulate in poultry and wild birds, causing considerable concern for veterinary and public health in Asia, Europe and Africa. Natural transmission of HPAIV H5N1 from poultry to humans, resulting in infections associated with high mortality, and from poultry or wild birds to large felids and domestic cats has been reported. Experimental infection of cats with HPAIV H5N1 derived from a human patient resulted in lethal disease. The role of cats in the adaptation of HPAIV H5N1 to mammals and vaccination regimens for the eventual protection of cats, however, remain to be elucidated. Here, it was shown that cats can be protected against a lethal high-dose challenge infection by an inactivated, adjuvanted heterologous H5N6 avian influenza virus vaccine. The challenge HPAIV H5N1 was derived from a naturally infected cat. In non-vaccinated cats, low-dose exposure resulted in asymptomatic infections with minimal virus excretion. As diseased cats can transmit the infection to naïve contact animals, the epidemiological role of H5N1-infected cats in endemically infected areas as a link between wild birds, poultry and humans needs close inspection, and vaccination of cats should be considered to reduce possible human exposure.

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Guo, Qi, Ze Liu, Jingxia Gao, Jian Zhou, Wenzhu Hu, Yina Cun, Weidong Li et Guoyang Liao. « Immunogenicity and Safety of Pandemic Influenza H5N1 Vaccines in Healthy Adults through Meta-Analysis ». Cellular Physiology and Biochemistry 40, n^o 5 (2016) : 921–32. http://dx.doi.org/10.1159/000453150.

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Background: There are sporadic cases and local outbreaks of H5N1 avian influenza virus worldwide every year. The World Health Organization (WHO) has paid close attention to the avian influenza epidemic trend. Avian influenza vaccines (AIV) are considered to be useful when an epidemic occurs. However, the use of AIV for humans is not yet widespread. Methods: This study assessed the immunogenicity and safety of pandemic influenza H5N1 vaccines with inactivated whole virus, split virus and subunit virus vaccines for healthy adults. We searched the databases of the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Excerpata Medica Database (EMBASE) and China National Knowledge Infrastructure (CNKI). The data from randomized trials regarding the immunogenicity and safety of AIV with or without different types of adjuvants for healthy adults (with an age range from 18 to 60 years) were collected. Results: According to this study, the most effective doses of H5N1 AIV ranged from 3.75 µg to 7.5 µg Hemagglutinin (HA) antigen. Aluminium adjuvants were administered with the same vaccine dose as a no-adjuvant group and induced the same immune effects. However, novel adjuvants (MF59 and AS03) were used with a smaller dose of vaccine than the no-adjuvant groups and successfully stimulated the body to produce more effective antibodies. Conclusion: All of the H5N1 AIV surveyed in this study were well tolerated without serious adverse reactions.

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Miller, Darren S., John Finnie, Timothy R. Bowden, Anita C. Scholz, Sawyin Oh, Tuckweng Kok, Christopher J. Burrell, Lee Trinidad, David B. Boyle et Peng Li. « Preclinical efficacy studies of influenza A haemagglutinin precursor cleavage loop peptides as a potential vaccine ». Journal of General Virology 92, n^o 5 (1 mai 2011) : 1152–61. http://dx.doi.org/10.1099/vir.0.028985-0.

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A universal influenza vaccine that does not require annual reformulation would have clear advantages over the currently approved seasonal vaccine. In this study, we combined the mucosal adjuvant alpha-galactosylceramide (αGalCer) and peptides designed across the highly conserved influenza precursor haemagglutinin (HA0) cleavage loop as a vaccine. Peptides designed across the HA0 of influenza A/H3N2 viruses, delivered to mice via the intranasal route with αGalCer as an adjuvant, provided 100 % protection following H3N2 virus challenge. Similarly, intranasal inoculation of peptides across the HA0 of influenza A/H5N1 with αGalCer completely protected mice against heterotypic challenge with H3N2 virus. Our data suggest that these peptide vaccines effectively inhibited subsequent influenza A/H3N2 virus replication. In contrast, only 20 % of mice vaccinated with αGalCer-adjuvanted peptides spanning the HA0 of H5N1 survived homologous viral challenge, possibly because the HA0 of this virus subtype is cleaved by intracellular furin-like enzymes. Results of these studies demonstrated that HA0 peptides adjuvanted with αGalCer have the potential to form the basis of a synthetic, intranasal influenza vaccine.

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Liu, Feng, Kathy Hancock, Jacqueline Katz, Jeffery Fairman et Xiuhua Lu. « A cationic lipid/DNA complexes (JVRS-100) combined with influenza A H5N1 vaccine induce long-term antibody responses and protection against H5N1 virus in BALB/c mice (155.31) ». Journal of Immunology 186, n^o 1_Supplement (1 avril 2011) : 155.31. http://dx.doi.org/10.4049/jimmunol.186.supp.155.31.

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Abstract Highly pathogenic avian influenza A H5N1 viruses pose a pandemic threat. An adjuvant is needed due to poor immunogenicity of pre-pandemic H5N1 vaccine in humans. JVRS-100 is a novel adjuvant, composed of cationic liposomes and plasmid DNA. Here, we investigated the long-term immunogenicity and protective efficacy of JVRS-100-adjuvanted H5N1 vaccine in mice. One year after immunization with one dose of vaccine with or without JVRS-100 adjuvant, significantly higher levels of hemagglutination-inhibition antibody and IgG antibody could be detected in serum of mice immunized with adjuvanted vaccine compared to that of mice receiving vaccine only. No or limited waning of antibody response was observed up to one year after immunization. IgG2a clearly predominated in serum of mice that received adjuvanted vaccine, suggesting that JVRS-100 preferentially stimulates a Th1 response. Mice were challenged with a high lethal dose of H5N1 virus 14 months after immunization. Co-administration of JVRS-100 with H5N1 vaccine significantly reduced virus titers in the lungs and brains and completely protected mice from severe disease and death. Our results indicate that the addition of JVRS-100 to H5N1 vaccine enhanced long-term antibody responses and protection against H5N1 virus lethal disease in mice. Therefore, JVRS-100 warrants further investigation as a potential adjuvant for use in human vaccination against avian influenza viruses with pandemic potential.

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Liu, Feng, Terrence Tumpey, Xiangjie Sun, Jeff Fairman, Min Levine, Jacqueline Katz et Xiuhua Lu. « A cationic lipid-DNA complex adjuvant (JVRS-100) enhances the immunogenicity and cross-protective efficacy of influenza pre-pandemic H5N1 vaccine in ferrets (VAC2P.931) ». Journal of Immunology 192, n^o 1_Supplement (1 mai 2014) : 72.9. http://dx.doi.org/10.4049/jimmunol.192.supp.72.9.

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Abstract Highly pathogenic avian influenza A H5N1 viruses continue to pose a public health threat. Adjuvants are needed to improve the immunogenicity of H5N1 vaccine in humans. JVRS-100 is a cationic lipid-DNA complex adjuvant. We investigated the immunogenicity and cross-protective efficacy of JVRS-100-adjuvanted H5N1 (clade 2.2) vaccine in ferrets. Four weeks after the first vaccination, significantly higher levels of serum hemagglutination-inhibition (HI), neutralizing and H5 IgG antibody were detected in ferrets immunized with adjuvanted vaccine compared to the unadjuvanted vaccine group. Following a second dose of JVRS-100 adjuvanted vaccine, cross-reactive HI antibody titers of ≥40 were detected against viruses from multiple H5N1 clades. Ferrets were challenged with a high lethal dose of heterologous H5N1 virus (clade 2.1.3.2) 2 months after the second vaccination. Ferrets that received JVRS-100 adjuvanted vaccine had significantly reduced virus titers in the nasal washes and were completely protected from severe disease and death. In contrast, ferrets that received unadjuvanted vaccine had high viral titers through day 6 and 3 of 6 animals succumbed to the lethal infection. Our results indicate that the addition of JVRS-100 to H5N1 vaccine enhanced immunogenicity and cross-protection against lethal H5N1 virus disease in ferrets. JVRS-100 warrants further investigation as a potential adjuvant for use in human vaccination against avian influenza viruses with pandemic potential.

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Larionova, N. V., I. V. Kiseleva, E. M. Doroshenko et L. G. Rudenko. « PECULARITIES OF DEVELOPMENT OF REASSORTANT STRAINS FOR LIVE INFLUENZA VACCINE BASED ON VIRUSES WITH PANDEMIC POTENTIAL ». Medical academic journal 18, n^o 2 (15 juin 2018) : 54–62. http://dx.doi.org/10.17816/maj18254-62.

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Objective of the research: to characterize the effectiveness of obtaining reassortant strains for live influenza vaccine based on pandemic and potentially pandemic influenza viruses which are new for humans. Materials and methods of the research: influenza virus A(H1N1)pdm09, potentially pandemic A(H3N2)v and A(H5N1) influenza viruses, a master donor virus for the Russian live influenza vaccine. Virological and molecular genetics methods of research. Results: strains with a 6:2 genome composition for live influenza reassortant vaccine based on the pandemic '(H1N1)pdm09 virus and swine influenza A(H3N2)v virus have been successfully obtained. The reassortment of highly pathogenic avian influenza (HPAI) viruses A(H5N1) and human A(H2N2) master donor virus for live attenuated influenza vaccine is complicated by the features of the constellation of their genes. H5N2 reassortants which inherited only HA gene from HPAI viruses of avian influenza were obtained. Despite the impossibility of development of 6:2 reassortants, the phenotypic, preclinical characteristics of the reassortants with the 7:1 genome composition, and their further clinical studies on volunteers have shown that such vaccine strains can be successfully used to prevent diseases caused by avian influenza viruses. Conclusion. When vaccine strains against potentially pandemic influenza viruses are obtained by the classical reassortment technique then the success depends on the mutual constellation of genes of phylogenetically distant far apart parental viruses. In some cases the inheritance by the reassortant of a single HA gene from the antigenic actual virus can be a compromise for LAIV development.

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Ryder, Alex B., Linda Buonocore, Leatrice Vogel, Raffael Nachbagauer, Florian Krammer et John K. Rose. « A Viable Recombinant Rhabdovirus Lacking Its Glycoprotein Gene and Expressing Influenza Virus Hemagglutinin and Neuraminidase Is a Potent Influenza Vaccine ». Journal of Virology 89, n^o 5 (24 décembre 2014) : 2820–30. http://dx.doi.org/10.1128/jvi.03246-14.

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ABSTRACTThe emergence of novel influenza viruses that cause devastating human disease is an ongoing threat and serves as an impetus for the continued development of novel approaches to influenza vaccines. Influenza vaccine development has traditionally focused on producing humoral and/or cell-mediated immunity, often against the viral surface glycoproteins hemagglutinin (HA) and neuraminidase (NA). Here, we describe a new vaccine candidate that utilizes a replication-defective vesicular stomatitis virus (VSV) vector backbone that lacks the native G surface glycoprotein gene (VSVΔG). The expression of the H5 HA of an H5N1 highly pathogenic avian influenza virus (HPAIV), A/Vietnam/1203/04 (VN1203), and the NA of the mouse-adapted H1N1 influenza virus A/Puerto Rico/8/34 (PR8) in the VSVΔG vector restored the ability of the recombinant virus to replicate in cell culture, without the requirement for the addition of trypsin. We show here that this recombinant virus vaccine candidate was nonpathogenic in mice when given by either the intramuscular or intranasal route of immunization and that thein vivoreplication of VSVΔG-H5N1 is profoundly attenuated. This recombinant virus also provided protection against lethal H5N1 infection after a single dose. This novel approach to vaccination against HPAIVs may be widely applicable to other emerging strains of influenza virus.IMPORTANCEPreparation for a potentially catastrophic influenza pandemic requires novel influenza vaccines that are safe, can be produced and administered quickly, and are effective, both soon after administration and for a long duration. We have created a new influenza vaccine that utilizes an attenuated vesicular stomatitis virus (VSV) vector, to deliver and express influenza virus proteins against which vaccinated animals develop potent antibody responses. The influenza virus hemagglutinin and neuraminidase proteins, expressed on the surface of VSV particles, allowed this vaccine to grow in cell culture and induced a potent antibody response in mice that was effective against infection with a lethal influenza virus. The mice showed no adverse reactions to the vaccine, and they were protected against an otherwise lethal influenza infection after only 14 days postvaccination and after as many as 140 days postvaccination. The ability to rapidly produce this safe and effective vaccine in cell culture is additionally advantageous.

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