Journal articles: 'Single radial haemolysis'

1

Wood, J. M., D. Melzack, R. W. Newman, D. L. Major, M. Zambon, K. G. Nicholson, and A. Podda. "A single radial haemolysis assay for antibody to H5 haemagglutinin." International Congress Series 1219 (October 2001): 761–66. http://dx.doi.org/10.1016/s0531-5131(01)00410-1.

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Tiwari, A. K., and B. S. Negi. "Single radial haemolysis for the detection of goat pox virus antigen and antibody." Tropical Animal Health and Production 28, no. 1 (March 1996): 117–20. http://dx.doi.org/10.1007/bf02250735.

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Adlard, P., and K. Bryett. "Influenza Immunization in Children with Cystic Fibrosis." Journal of International Medical Research 15, no. 6 (November 1987): 344–51. http://dx.doi.org/10.1177/030006058701500603.

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Nineteen children with cystic fibrosis and aged between 5 and 13 years were randomized to receive two doses at monthly intervals of either a split-virion influenza vaccine (MFV-Ject, Institut Merieux) or a sub-unit vaccine (Fluvirin, Evans). In those completing the study, there was a satisfactory serological response. There was no statistically significant difference between the immunogenicity of the two vaccines as evaluated by haemagglutination inhibition or single radial haemolysis tests. The incidence of local side-effects was similar in the two groups.

4

Mumford, J. A., J. M. Wood, C. Folkers, and G. C. Schild. "Protection against experimental infection with influenza virus A/equine/Miami/63 (H3N8) provided by inactivated whole virus vaccines containing homologous virus." Epidemiology and Infection 100, no. 3 (June 1988): 501–10. http://dx.doi.org/10.1017/s0950268800067236.

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SummaryThirty-one ponies immunized with inactivated virus vaccine containing A/equine/Miami/63 (H3N8) virus and six seronegative ponies were experimentally challenged with the homologous virus strain. All G unvaccinated ponies and 11 out of 31 vaccinated ponies became infected. A clear relationship between pre-challenge antibody, measured by single radial haemolysis (SRH), and protection was demonstrated as judged by virus excretion, febrile responses and antibody responses. Those ponies with SRH antibody levels > 74 mm2 were completely protected against challenge infection by the intranasal route.

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Trombetta, Claudia Maria, Daniele Perini, Licia Vitale, Rebecca Jane Cox, Valerio Stanzani, Simona Piccirella, and Emanuele Montomoli. "Validation of Single Radial Haemolysis assay: A reliable method to measure antibodies against influenza viruses." Journal of Immunological Methods 422 (July 2015): 95–101. http://dx.doi.org/10.1016/j.jim.2015.04.009.

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Ebeid, Eman, Nehal Saleh, and Nashwa Madkour. "Comparative measurement of Equine influenza virus antibodies by single radial haemolysis and haemagglutination inhibition tests." Journal of Current Veterinary Research 10, no. 1 (September 1, 2016): 72–79. http://dx.doi.org/10.21608/jcvr.2016.37889.

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Carnell, George W., Claudia M. Trombetta, Francesca Ferrara, Emanuele Montomoli, and Nigel J. Temperton. "Correlation of Influenza B Haemagglutination Inhibiton, Single-Radial Haemolysis and Pseudotype-Based Microneutralisation Assays for Immunogenicity Testing of Seasonal Vaccines." Vaccines 9, no. 2 (January 28, 2021): 100. http://dx.doi.org/10.3390/vaccines9020100.

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Influenza B is responsible for a significant proportion of the global morbidity, mortality and economic loss caused by influenza-related disease. Two antigenically distinct lineages co-circulate worldwide, often resulting in mismatches in vaccine coverage when vaccine predictions fail. There are currently operational issues with gold standard serological assays for influenza B, such as lack of sensitivity and requirement for specific antigen treatment. This study encompasses the gold standard assays with the more recent Pseudotype-based Microneutralisation assay in order to study comparative serological outcomes. Haemagglutination Inhibition, Single Radial Haemolysis and Pseudotype-based Microneutralisation correlated strongly for strains in the Yamagata lineage; however, it correlated with neither gold standard assays for the Victoria lineage.

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Gibson, C. A., J. M. Wood, Jennifer Mumford, G. C. Schild, and Averil M. Bevan. "A single-radial haemolysis technique for measurement of antibody to influenza virus neuraminidase in equine sera." Journal of Virological Methods 11, no. 4 (August 1985): 299–308. http://dx.doi.org/10.1016/0166-0934(85)90023-0.

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MYHRVOLD, VESLEMØY. "THE USE OF FROZEN ERYTHROCYTES IN THE SINGLE RADIAL HAEMOLYSIS TEST (SRHT) FOR ANTIBODIES TO RUBELLA VIRUS." Acta Pathologica Microbiologica Scandinavica Section B Microbiology 89B, no. 1-6 (August 19, 2009): 103–7. http://dx.doi.org/10.1111/j.1699-0463.1981.tb00160_89b.x.

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Mumford, J. A., H. Wilson, D. Hannant, and D. M. Jessett. "Antigenicity and immunogenicity of equine influenza vaccines containing a Carbomer adjuvant." Epidemiology and Infection 112, no. 2 (April 1994): 421–37. http://dx.doi.org/10.1017/s0950268800057848.

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SUMMARYEquine influenza vaccines containing inactivated whole virus and Carbomer adjuvant stimulated higher levels and longer lasting antibody to haemagglutinin in ponies than vaccines of equivalent antigenic content containing aluminium phosphate adjuvants. Five months after the third dose of vaccine containing Carbomer adjuvant, ponies were protected against clinical disease induced by an aerosol of virulent influenza virus (A/equine/Newmarket/79, H3N8). In contrast ponies which received vaccine containing aluminium phosphate adjuvant were susceptible to infection and disease. There was an inverse correlation between prechallenge levels of antibody detected by single radial haemolysis (SRH) and duration of virus excretion, pyrexia and coughing. All ponies with antibody levels equivalent to SRH zones of ≥ 154 mm2 were protected against infection and all those with levels ≤ 85 mm2 were protected from disease.

11

Kearney, Raymond. "Blocking of IgM-Mediated Single Radial Haemolysis by IgA and Non-Complement-Fixing IgM Anti-Type-III Pneumococcal Antibodies." International Archives of Allergy and Immunology 80, no. 1 (1986): 57–61. http://dx.doi.org/10.1159/000234026.

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12

Pemberton, R. M., R. Jennings, and T. L. Smith. "Morphology and antigenicity studies on reassortant influenza (H3N2) viruses for use in inactivated vaccines." Journal of Hygiene 94, no. 2 (April 1985): 229–39. http://dx.doi.org/10.1017/s002217240006143x.

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SUMMARYThree influenza A (H3N2) reassortant whole virus vaccine strains with differing antibody-inducing capacities in hamsters were investigated morphologically and antigenically. Although initial measurements of virion circumference, from electron micrographs of vaccine preparations, suggested a relationship of small virion size with low immunogenicity, subsequent immunization with, and morphological investigation of, vaccine virions separated on sucrose gradients, failed to obtain populations whose antibody-inducing capacity clearly correlated with constituent virion density, size, morphology or integrity.However, antigenic investigation using single radial haemolysis (SRH) and monoclonal antibodies revealed significant differences in antigenic specificity between the strains. Furthermore, a series of H3N2 isolates, derived using standard reassortment procedures, also showed differences in antigenic specificity in their haemagglutination-inhibition (HI) reactions with monoclonal antibodies after five passages in allantois-on-shell cultures. Variation between these isolates and their A/Victoria parent virus could be detected using SRH and hamster sera raised against each isolate.These results demonstrate variation between candidate influenza A virus vaccine strains, all possessing the same surface (H3N2) glycoproteins, expressed as a consequence of the reassortant system used for their production.

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Wang, Biao, Margaret L. Russell, Angela Brewer, Jennifer Newton, Pardeep Singh, Brian J. Ward, and Mark Loeb. "Single radial haemolysis compared to haemagglutinin inhibition and microneutralization as a correlate of protection against influenza A H3N2 in children and adolescents." Influenza and Other Respiratory Viruses 11, no. 3 (March 16, 2017): 283–88. http://dx.doi.org/10.1111/irv.12450.

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Iorio, A. M., T. Zei, M. Neri, L. Campitelli, M. R. Castrucci, and I. Donatelli. "Immunization of elderly volunteers with the 1988?89 inactivated whole influenza vaccine: Assessment of antibody responses by haemagglutination inhibition and single radial haemolysis tests." European Journal of Epidemiology 8, no. 4 (July 1992): 491–97. http://dx.doi.org/10.1007/bf00146365.

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Cullinane, Ann, Jacinta Gahan, Cathal Walsh, Manabu Nemoto, Johanna Entenfellner, Cecilia Olguin-Perglione, Marie Garvey, et al. "Evaluation of Current Equine Influenza Vaccination Protocols Prior to Shipment, Guided by OIE Standards." Vaccines 8, no. 1 (February 29, 2020): 107. http://dx.doi.org/10.3390/vaccines8010107.

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To facilitate the temporary importation of horses for competition and racing purposes, with a minimum risk of transmitting equine influenza, the World Organisation for Animal Health (Office International des Epizooties, or OIE), formally engaged in a public–private partnership with the Federation Equestre Internationale (FEI) and the International Federation for Horseracing Authorities (IFHA) to establish, within the context of existing OIE standards, a science-based rationale to identify the ideal time period for equine influenza vaccination prior to shipment. Field trials using vaccines based on different technologies were carried out on three continents. The antibody response post-booster vaccination at intervals aligned with the different rules/recommendations of the OIE, FEI, and IFHA, was monitored by single radial haemolysis. It was determined that 14 days was the optimum period necessary to allow horses adequate time to respond to booster vaccination and for horses that have previously received four or more doses of vaccine and are older than four years, it is adequate to allow vaccination within 180 days of shipment. In contrast, the results indicate that there is a potential benefit to younger (four years old or younger) horses in requiring booster vaccination within 90 days of shipment, consistent with the current OIE standard.

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Entenfellner, Johanna, Jacinta Gahan, Marie Garvey, Cathal Walsh, Monica Venner, and Ann Cullinane. "Response of Sport Horses to Different Formulations of Equine Influenza Vaccine." Vaccines 8, no. 3 (July 10, 2020): 372. http://dx.doi.org/10.3390/vaccines8030372.

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The international governing body of equestrian sports requires that horses be vaccinated against equine influenza within 6 months and 21 days of competing. The aim of this study was to compare the antibody response of young sport horses to six-monthly booster vaccination with equine influenza vaccines of different formulations. An inactivated vaccine was allocated to 35 horses and subunit and recombinant vaccines were allocated to 34 horses each. After vaccination, all horses were monitored for evidence of adverse reactions. Whole blood samples were collected at the time of vaccination and on nine occasions up to six months and 21 days post vaccination. Antibodies against equine influenza were measured by single radial haemolysis. Transient fever and injection site reactions were observed in several horses vaccinated with each vaccine. Only two horses failed to seroconvert post booster vaccination but there was a delayed response to the recombinant vaccine. The antibody response to the recombinant vaccine was lower than that induced by the whole-inactivated and subunit vaccines up to three months post vaccination. Thereafter, there was no significant difference. By six months post vaccination, the majority of horses in all three groups were clinically but not virologically protected. There was minimal decline in antibody titres within the 21-day grace period.

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Carnet, Flora, Romain Paillot, Christine Fortier, Erika S. Hue, Laurie Briot, Frédéric de Geoffroy, Pierre-Olivier Vidalain, and Stéphane Pronost. "Immunostimulating Effect of Inactivated Parapoxvirus Ovis on the Serological Response to Equine Influenza Booster Vaccination." Vaccines 10, no. 12 (December 14, 2022): 2139. http://dx.doi.org/10.3390/vaccines10122139.

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Equine influenza virus (EIV) is responsible for recurring outbreaks that are detrimental to the equine industry. Vaccination is key for prevention, but the effectiveness and duration of protection provided by existing vaccines is often insufficient. In order to improve vaccine efficacy, we evaluated the benefit of immune stimulation with inactivated Parapoxvirus ovis (iPPVO) on the antibody response induced by a vaccine boost against EIV. A whole inactivated ISCOMatrix-adjuvanted equine influenza vaccine was administered alone (n = 10) or combined with iPPVO injections at D0, D2 and D4 post vaccination (n = 10) to adult horses that required a vaccine boost 6 months after the last immunization, as now recommended by the WOAH. Antibody levels were measured with the single radial haemolysis (SRH) assay at 1, 3 and 6 months post-vaccination. Results revealed that horses that received iPPVO had higher antibody levels than the control group injected with the EI vaccine alone. Although the vaccine used contains only a clade 1 and European lineage strain, the increase in protective antibodies was also observed against a clade 2 strain. Thus, immune stimulation with iPPVO, a substance already marketed as an immunostimulant, could be used to improve vaccination protocols in horses and potentially other species.

18

Traavik, Terje, Reidar Mehl, and Richard Wiger. "Mosquito-borne arboviruses in Norway: further isolations and detection of antibodies to California encephalitis viruses in human, sheep and wildlife sera." Journal of Hygiene 94, no. 1 (February 1985): 111–22. http://dx.doi.org/10.1017/s0022172400061180.

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SUMMARYSeven virus strains antigenically related to the California encephalitis (CE) virus group were isolated from NorwegianAedesspp. mosquitoes collected in 1976. So far CE viruses have been isolated from five differentAedesspp. in Norway. Furthermore, two virus strains related to the Bunyamwera group were isolated fromAnopheles claviger.Antibodies to CE viruses were demonstrated in 22% of 1014 military recruits tested. Among 91 soldiers who were monitored by monthly blood samples during the mosquito season, seroconversions were detected in 11 individuals. Specific IgM antibodies were found in seven of them. Disease symptoms in connexion with the CE virus infections were not seen. The prevalence of CE antibodies in patients with CNS or respiratory infections was not higher than in control groups. Seroconversions were not seen in any of the groups.Screening of sheep sera from six different areas in northern Norway indicated significantly different degrees of CE virus activity. Passerine birds may be important CE virus hosts, while small rodents seem unimportant. Specific IgM antibodies were detected in the sera of one of three hares and one of two squirrels.Of the methods used, single radial haemolysis (SRH) and immuno-electroosmophoresis (IEOP) seemed to be well suited for serological screenings. However, an indirect immunofluorescence antibody test (IFAT) which was used may be an attractive alternative if high-quality anti-species conjugates are available. The haemagglutination-inhibition (HI) test used gave a high number of false positive results.

19

Kinsley, Rebecca, Stéphane Pronost, Manuelle De Bock, Nigel Temperton, Janet M. Daly, Romain Paillot, and Simon Scott. "Evaluation of a Pseudotyped Virus Neutralisation Test for the Measurement of Equine Influenza Virus-Neutralising Antibody Responses Induced by Vaccination and Infection." Vaccines 8, no. 3 (August 21, 2020): 466. http://dx.doi.org/10.3390/vaccines8030466.

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Equine influenza is a major respiratory disease of horses that is largely controlled by vaccination in some equine populations. Virus-neutralising antibodies, the mainstay of the protective immune response, are problematic in assaying for equine influenza virus, as most strains do not replicate efficiently in cell culture. Surrogate measures of protective antibody responses include the haemagglutination inhibition (HI) test and single radial haemolysis (SRH) assay. For this study, a pseudotyped virus, bearing an envelope containing the haemagglutinin (HA) from the Florida clade 2 equine influenza virus strain A/equine/Richmond/1/07 (H3N8), was generated to measure HA-specific neutralising antibodies in serum samples (n = 134) from vaccinated or experimentally-infected ponies using a pseudotyped virus neutralization test (PVNT). Overall, the results of PVNT were in good agreement with results from the SRH assay (100% sensitivity, 68.53% specificity) and HI test (99.2% sensitivity, 49.03% specificity). The PVNT was apparently more sensitive than either the SRH assay or the HI test, which could be advantageous for studying the antibody kinetics, particularly when antibody levels are low. Nevertheless, further studies are required to determine whether a protective antibody level can be defined for the SRH assay and to ascertain the inter-laboratory reproducibility. In conclusion, the PVNT efficiently measures neutralising antibodies after immunization and/or experimental infection in the natural host, and may complement existing antibody assays.

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Ricci, Ida, Silvia Tofani, Davide Lelli, Giacomo Vincifori, Francesca Rosone, Andrea Carvelli, Elena Lavinia Diaconu, et al. "First Reported Circulation of Equine Influenza H3N8 Florida Clade 1 Virus in Horses in Italy." Animals 14, no. 4 (February 12, 2024): 598. http://dx.doi.org/10.3390/ani14040598.

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Background: Equine influenza (EI) is a highly contagious viral disease of equids characterized by pyrexia and respiratory signs. Like other influenza A viruses, antigenic drift or shift could lead to a vaccine-induced immunity breakdown if vaccine strains are not updated. The aim of this study was to genetically characterize EIV strains circulating in Italy, detected in PCR-positive samples collected from suspected cases, especially in the absence of formal active surveillance. Methods: Between February and April 2019, blood samples and nasal swabs collected from each of the 20 symptomatic horses from North and Central Italy were submitted to the National Reference Centre for Equine Diseases in Italy to confirm preliminary analysis performed by other laboratories. Results: None of the sera analysed using haemagglutination inhibition and single radial haemolysis presented a predominant serological reactivity pattern for any antigen employed. All nasal swabs were positive with IAV RRT-PCR. Only one strain, isolated in an embryonated chicken egg from a sample collected from a horse of a stable located in Brescia, Lombardy, was identified as H3N8 Florida lineage clade 1 (FC1). In the constructed phylogenetic trees, this strain is located within the FC1, together with the virus isolated in France in 2018 (MK501761). Conclusions: This study reports the first detection of H3N8 FC1 in Italy, highlighting the importance of monitoring circulating EIV strains to verify the vaccine composition appropriateness for maximum efficacy.

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Olufemi, Olaolu T., Emmanuel R. Edeh, Mustapha S. Isyaku, Mustapha Haliru, Shafiu Samaila, Philip W. Mshelia, Olajide A. Owolodun, J. Richard Newton, and Janet M. Daly. "Seroprevalence of Equine Influenza and Its Associated Risk Factors in Northwest Nigeria." Pathogens 11, no. 11 (November 17, 2022): 1372. http://dx.doi.org/10.3390/pathogens11111372.

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Equine influenza (EI) is a fast-spreading respiratory disease of equids caused by equine influenza A virus (EIV), often resulting in high morbidity and a huge economic impact on the equine industry globally. In this cross-sectional study to determine the seroprevalence of EI and its associated risk factors, sera from 830 horses bled on a single occasion in Northwest Nigeria between October 2019 and January 2020 were screened for antibodies to A/equine/Richmond/1/2007 (H3N8) using the single radial haemolysis (SRH) assay. Antibodies were detected in 71.3% (592/830, 95% CI: 68–74%) of horses (SRH area ≥ 0.5 mm2). Although there were statistically significant univariable associations between seropositivity and age, sex, breed, purpose and coat colour, only age remained significant when included with each of the other variables in bivariable analyses. There was a clear trend for increasing odds of seropositivity with increasing age: OR 1.6, 95% CI: 1.05–2.40 (p = 0.03) for 5–14-year-olds and OR 8.13, 95% CI: 2.75–24.1 (p < 0.001) for ≥15-year-olds compared to horses <5 years old. The mean SRH value was 78.2 mm2 (median = 88 mm2, interquartile range = 0–121 mm2) with only 9% of the horses having an SRH value > 150 mm2, considered sufficient to protect against clinical disease and virus shedding. Comparative screening of a subset of the horses (n = 118) with a 2019 H3N8 virus (A/equine/Worcestershire/2019) revealed a significantly greater seropositivity (p = 0.0001) than A/equine/Richmond/1/2007 consistent with exposure of the population during a widespread outbreak of EI in the region in 2019. In conclusion, there was an insufficient level of protection against EI in the region and introduction of a vaccination programme with vaccines containing recently circulating virus is recommended to mitigate against further outbreaks of EI in Nigeria.

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Razi, A., A. Azimian, R. Arezumand, A. Solati, and H. N. Ahmadabad. "Associations between serum levels of C3, C4, and total classical complement activity in COVID-19 patients at the time of admission and clinical outcome." Russian Journal of Infection and Immunity 12, no. 5 (November 16, 2022): 869–74. http://dx.doi.org/10.15789/2220-7619-abs-1925.

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In the present study, we investigated the association between complement system status at the time of admission and clinical outcomes in COVID-19 patients. This single-center study was carried out with sixty-one adult patients with COVID-19 who were hospitalized at Imam Hassan Hospital of North Khorasan University of Medical Sciences (Bojnurd, Iran) with less than three days passage since onset of COVID-19 symptoms. Twenty-three healthy volunteers with demographic features similar to the patient group (matched by age and gender) were included in the study as a control group. Patient information including demographic information, demographic data, clinical characteristics, and clinical outcomes were obtained from electronic medical records. Of 61 hospitalized patients with COVID-19, 28 (47.54%) were female, and the average age was 48.78.8 years. The healthy control group included 23 cases (11 (47.8%) female, 12 (52.1%) males, mean age 46.44.4 years). Twenty-one of the 61 patients (34.4%) were admitted to the ICU, and sixteen of them (26.2%) died. Thirty-three (54.10%) patients with COVID-19 were hospitalized for less than 7 days, and 28 (45.90%) of them were hospitalized for 7 days. Our results show that length of hospital stay in the no-ICU group was significantly lower than the ICU admission or death groups (6.490.24 vs. 8.851.59 and 10.531.80, p = 0.0002). The levels of C3, C4, and CH50 were determined through the immunoturbidimetric method and single-radial-haemolysis plates, respectively, on serum samples obtained from patients at the time of admission or those in the control group. Our results indicate that C3, C4 and CH50 levels were markedly lower in COVID-19 patients than in the control group. We also found that complement parameter levels in COVID-19 patients who died or were admitted to ICU were significantly lower than in non-ICU COVID-19 patients. In general, it seems that serum level of C3, C4, and CH50 at admission may predict disease progression or adverse clinical outcome in COVID-19 patients.

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Dilai, Mohamed, Mohammed Piro, Mehdi El Harrak, Stéphanie Fougerolle, Mohammed Dehhaoui, Asmaa Dikrallah, Loïc Legrand, Romain Paillot, and Ouafaa Fassi Fihri. "Impact of Mixed Equine Influenza Vaccination on Correlate of Protection in Horses." Vaccines 6, no. 4 (October 4, 2018): 71. http://dx.doi.org/10.3390/vaccines6040071.

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To evaluate the humoral immune response to mixed Equine Influenza vaccination, a common practice in the field, an experimental study was carried out on 42 unvaccinated thoroughbred weanling foals divided into six groups of seven. Three groups were vaccinated using a non-mixed protocol (Equilis® Prequenza-Te, Proteqflu-Te® or Calvenza-03®) and three other groups were vaccinated using a mix of the three vaccines mentioned previously. Each weanling underwent a primary EI vaccination schedule composed of two primary immunisations (V1 and V2) four weeks apart followed by a third boost immunisation (V3) six months later. Antibody responses were monitored until one-year post-V3 by single radial haemolysis (SRH). The results showed similar antibody responses for all groups using mixed EI vaccination and the group exclusively vaccinated with Equilis® Prequenza-TE, which were significantly higher than the other two groups vaccinated with Proteqflu-TE® and Calvenza-03®. All weanlings (100%) failed to seroconvert after V1 and 21% (9/42) still had low or no SRH antibody titres two weeks post-V2. All weanlings had seroconverted and exceeded the clinical protection threshold one month after V3. The poor response to vaccination was primarily observed in groups exclusively vaccinated with Proteqflu-Te® and Calvenza-03®. A large window of susceptibility (3–4.5-month duration) usually called immunity gap was observed after V2 and prior to V3 for all groups. The SRH antibody level was maintained above the clinical protection threshold for three months post-V3 for the groups exclusively vaccinated with Proteqflu-Te® and Calvenza-03®, and six months to one year for groups using mixed EI vaccination or exclusively vaccinated with Equilis® Prequenza-Te. This study demonstrates for the first time that the mix of EI vaccines during the primary vaccination schedule has no detrimental impact on the correlate of protection against EIV infection.

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Nair, Dileep G., Bryan G. Fry, Paul Alewood, Prakash P. Kumar, and R. Manjunatha Kini. "Antimicrobial activity of omwaprin, a new member of the waprin family of snake venom proteins." Biochemical Journal 402, no. 1 (January 25, 2007): 93–104. http://dx.doi.org/10.1042/bj20060318.

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We have isolated and characterized omwaprin, a 50-amino-acid cationic protein from the venom of inland taipan (Oxyuranus microlepidotus). It is a new member of the waprin family of snake venom proteins. A synthetic gene was designed and constructed for expressing the recombinant protein in Escherichia coli. Recombinant omwaprin was used for carrying out functional analyses. The protein is non-toxic to Swiss albino mice at doses of up to 10 mg/kg when administered intraperitoneally. However, it shows selective and dose-dependant antibacterial activity against Gram-positive bacteria. The minimum inhibitory doses were in the range 2–10 μg for selected species of bacteria in radial diffusion assays. The antibacterial activity is salt-tolerant up to 350 mM NaCl. However, omwaprin lost its antibacterial activity upon reduction and alkylation of its cysteine residues, or upon deletion of six N-terminal amino acid residues, four of which are positively charged. These observations indicate that the three-dimensional structure constrained by four disulfide bonds and the N-terminal residues are essential for its activity. The mechanism of action is via membrane disruption, as shown by scanning electron microscopy. Importantly, omwaprin lacks haemolytic activity on human erythrocytes. This demonstrates the specificity of omwaprin for bacterial membranes. Unlike other reported WAP (whey acidic protein) domain-containing antibacterial proteins, including elafin, EPPIN (epididymal proteinase inhibitor), SWAM1 and SWAM2 [single WAP (whey acidic protein) motif proteins 1 and 2] and SLPI (secretory leucocyte proteinase inhibitor), omwaprin shows species-specific activity on the Gram-positive bacteria tested.

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Smith, T. L., R. Jennings, and C. W. Potter. "Use of single radial haemolysis for assessing antibody response to influenza virus vaccines in animals." Medical Microbiology and Immunology 176, no. 6 (October 1987). http://dx.doi.org/10.1007/bf00194892.

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26

Janssens, Yorick, Jasper Joye, Gwenn Waerlop, Frédéric Clement, Geert Leroux-Roels, and Isabel Leroux-Roels. "The role of cell-mediated immunity against influenza and its implications for vaccine evaluation." Frontiers in Immunology 13 (August 16, 2022). http://dx.doi.org/10.3389/fimmu.2022.959379.

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Influenza vaccines remain the most effective tools to prevent flu and its complications. Trivalent or quadrivalent inactivated influenza vaccines primarily elicit antibodies towards haemagglutinin and neuraminidase. These vaccines fail to induce high protective efficacy, in particular in older adults and immunocompromised individuals and require annual updates to keep up with evolving influenza strains (antigenic drift). Vaccine efficacy declines when there is a mismatch between its content and circulating strains. Current correlates of protection are merely based on serological parameters determined by haemagglutination inhibition or single radial haemolysis assays. However, there is ample evidence showing that these serological correlates of protection can both over- or underestimate the protective efficacy of influenza vaccines. Next-generation universal influenza vaccines that induce cross-reactive cellular immune responses (CD4+ and/or CD8+ T-cell responses) against conserved epitopes may overcome some of the shortcomings of the current inactivated vaccines by eliciting broader protection that lasts for several influenza seasons and potentially enhances pandemic preparedness. Assessment of cellular immune responses in clinical trials that evaluate the immunogenicity of these new generation vaccines is thus of utmost importance. Moreover, studies are needed to examine whether these cross-reactive cellular immune responses can be considered as new or complementary correlates of protection in the evaluation of traditional and next-generation influenza vaccines. An overview of the assays that can be applied to measure cell-mediated immune responses to influenza with their strengths and weaknesses is provided here.

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Sharma, Raman, Hema Sharma, Siôn Jones, Isabelle Borghini-Fuhrer, Gonzalo J. Domingo, Rachel A. Gibson, Katie Rolfe, et al. "Optimal balance of benefit versus risk for tafenoquine in the treatment of Plasmodium vivax malaria." Malaria Journal 23, no. 1 (May 13, 2024). http://dx.doi.org/10.1186/s12936-024-04924-z.

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AbstractA single 300 mg dose of tafenoquine (an 8-aminoquinoline), in combination with a standard 3-day course of chloroquine, is approved in several countries for the radical cure (prevention of relapse) of Plasmodium vivax malaria in patients aged ≥ 16 years. Despite this, questions have arisen on the optimal dose of tafenoquine. Before the availability of tafenoquine, a 3-day course of chloroquine in combination with the 8-aminoquinoline primaquine was the only effective radical cure for vivax malaria. The World Health Organization (WHO)-recommended standard regimen is 14 days of primaquine 0.25 mg/kg/day or 7 days of primaquine 0.5 mg/kg/day in most regions, or 14 days of primaquine 0.5 mg/kg/day in East Asia and Oceania, however the long treatment courses of 7 or 14 days may result in poor adherence and, therefore, low treatment efficacy. A single dose of tafenoquine 300 mg in combination with a 3-day course of chloroquine is an important advancement for the radical cure of vivax malaria in patients without glucose-6-phosphate dehydrogenase (G6PD) deficiency, as the use of a single-dose treatment will improve adherence. Selection of a single 300 mg dose of tafenoquine for the radical cure of P. vivax malaria was based on collective efficacy and safety data from 33 studies involving more than 4000 trial participants who received tafenoquine, including over 800 subjects who received the 300 mg single dose. The safety profile of single-dose tafenoquine 300 mg is similar to that of standard-dosage primaquine 0.25 mg/kg/day for 14 days. Both primaquine and tafenoquine can cause acute haemolytic anaemia in individuals with G6PD deficiency; severe haemolysis can lead to anaemia, kidney damage, and, in some cases, death. Therefore, relapse prevention using an 8-aminoquinoline must be balanced with the need to avoid clinical haemolysis associated with G6PD deficiency. To minimize this risk, the WHO recommends G6PD testing for all individuals before the administration of curative doses of 8-aminoquinolines. In this article, the authors review key efficacy and safety data from the pivotal trials of tafenoquine and argue that the currently approved dose represents a favourable benefit–risk profile.

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Pukrittayakamee, Sasithon, Podjanee Jittamala, James A. Watson, Borimas Hanboonkunupakarn, Pawanrat Leungsinsiri, Kittiyod Poovorawan, Kesinee Chotivanich, et al. "Primaquine in glucose-6-phosphate dehydrogenase deficiency: an adaptive pharmacometric assessment of ascending dose regimens in healthy volunteers." eLife 12 (February 6, 2024). http://dx.doi.org/10.7554/elife.87318.3.

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Background:Primaquine is an 8-aminoquinoline antimalarial. It is the only widely available treatment to prevent relapses of Plasmodium vivax malaria. The 8-aminoquinolines cause dose-dependent haemolysis in glucose-6-phosphate dehydrogenase deficiency (G6PDd). G6PDd is common in malaria endemic areas but testing is often not available. As a consequence primaquine is underused.Methods:We conducted an adaptive pharmacometric study to characterise the relationship between primaquine dose and haemolysis in G6PDd. The aim was to explore shorter and safer primaquine radical cure regimens compared to the currently recommended 8-weekly regimen (0.75 mg/kg once weekly), potentially obviating the need for G6PD testing. Hemizygous G6PDd healthy adult Thai and Burmese male volunteers were admitted to the Hospital for Tropical Diseases in Bangkok. In Part 1, volunteers were given ascending dose primaquine regimens whereby daily doses were increased from 7.5 mg up to 45 mg over 15–20 days. In Part 2 conducted at least 6 months later, a single primaquine 45 mg dose was given.Results:24 volunteers were enrolled in Part 1, and 16 in Part 2 (13 participated in both studies). In three volunteers, the ascending dose regimen was stopped because of haemolysis (n=1) and asymptomatic increases in transaminases (n=2; one was hepatitis E positive). Otherwise the ascending regimens were well tolerated with no drug-related serious adverse events. In Part 1, the median haemoglobin concentration decline was 3.7 g/dL (range: 2.1–5.9; relative decline of 26% [range: 15–40%]). Primaquine doses up to 0.87 mg/kg/day were tolerated subsequently without clinically significant further falls in haemoglobin. In Part 2, the median haemoglobin concentration decline was 1.7 g/dL (range 0.9–4.1; relative fall of 12% [range: 7–30% decrease]). The ascending dose primaquine regimens gave seven times more drug but resulted in only double the haemoglobin decline.Conclusions:In patients with Southeast Asian G6PDd variants, full radical cure treatment can be given in under 3 weeks compared with the current 8-week regimen.Funding:Medical Research Council of the United Kingdom (MR/R015252/1) and Wellcome (093956/Z/10/C, 223253/Z/21/Z).Clinical trial number:Thai Clinical Trial Registry: TCTR20170830002 and TCTR20220317004.

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Boonyuen, Usa, Duantida Songdej, Sasipa Tanyaratsrisakul, Suparat Phuanukoonnon, Kamonwan Chamchoy, Aun Praoparotai, Phonchanan Pakparnich, et al. "Glucose-6-phosphate dehydrogenase mutations in malaria endemic area of Thailand by multiplexed high‐resolution melting curve analysis." Malaria Journal 20, no. 1 (April 20, 2021). http://dx.doi.org/10.1186/s12936-021-03731-0.

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Abstract Background Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common enzymopathy in humans, is prevalent in tropical and subtropical areas where malaria is endemic. Anti-malarial drugs, such as primaquine and tafenoquine, can cause haemolysis in G6PD-deficient individuals. Hence, G6PD testing is recommended before radical treatment against vivax malaria. Phenotypic assays have been widely used for screening G6PD deficiency, but in heterozygous females, the random lyonization causes difficulty in interpreting the results. Over 200 G6PD variants have been identified, which form genotypes associated with differences in the degree of G6PD deficiency and vulnerability to haemolysis. This study aimed to assess the frequency of G6PD mutations using a newly developed molecular genotyping test. Methods A multiplexed high-resolution melting (HRM) assay was developed to detect eight G6PD mutations, in which four mutations can be tested simultaneously. Validation of the method was performed using 70 G6PD-deficient samples. The test was then applied to screen 725 blood samples from people living along the Thai–Myanmar border. The enzyme activity of these samples was also determined using water-soluble tetrazolium salts (WST-8) assay. Then, the correlation between genotype and enzyme activity was analysed. Results The sensitivity of the multiplexed HRM assay for detecting G6PD mutations was 100 % [95 % confidence interval (CI): 94.87–100 %] with specificity of 100 % (95 % CI: 87.66–100 %). The overall prevalence of G6PD deficiency in the studied population as revealed by phenotypic WST-8 assay was 20.55 % (149/725). In contrast, by the multiplexed HRM assay, 27.17 % (197/725) of subjects were shown to have G6PD mutations. The mutations detected in this study included four single variants, G6PD Mahidol (187/197), G6PD Canton (4/197), G6PD Viangchan (3/197) and G6PD Chinese-5 (1/197), and two double mutations, G6PD Mahidol + Canton (1/197) and G6PD Chinese-4 + Viangchan (1/197). A broad range of G6PD enzyme activities were observed in individuals carrying G6PD Mahidol, especially in females. Conclusions The multiplexed HRM-based assay is sensitive and reliable for detecting G6PD mutations. This genotyping assay can facilitate the detection of heterozygotes, which could be useful as a supplementary approach for high-throughput screening of G6PD deficiency in malaria endemic areas before the administration of primaquine and tafenoquine.

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Boonyuen, Usa, Beatriz Aira C. Jacob, Jutamas Wongwigkan, Kamonwan Chamchoy, Natsamon Singha-art, Natnicha Pengsuk, Duantida Songdej, et al. "Genetic analysis and molecular basis of G6PD deficiency among malaria patients in Thailand: implications for safe use of 8-aminoquinolines." Malaria Journal 23, no. 1 (February 2, 2024). http://dx.doi.org/10.1186/s12936-024-04864-8.

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Abstract Background It was hypothesized that glucose-6-phosphate dehydrogenase (G6PD) deficiency confers a protective effect against malaria infection, however, safety concerns have been raised regarding haemolytic toxicity caused by radical cure with 8-aminoquinolines in G6PD-deficient individuals. Malaria elimination and control are also complicated by the high prevalence of G6PD deficiency in malaria-endemic areas. Hence, accurate identification of G6PD deficiency is required to identify those who are eligible for malaria treatment using 8-aminoquinolines. Methods The prevalence of G6PD deficiency among 408 Thai participants diagnosed with malaria by microscopy (71), and malaria-negative controls (337), was assessed using a phenotypic test based on water-soluble tetrazolium salts. High-resolution melting (HRM) curve analysis was developed from a previous study to enable the detection of 15 common missense, synonymous and intronic G6PD mutations in Asian populations. The identified mutations were subjected to biochemical and structural characterisation to understand the molecular mechanisms underlying enzyme deficiency. Results Based on phenotypic testing, the prevalence of G6PD deficiency (< 30% activity) was 6.13% (25/408) and intermediate deficiency (30–70% activity) was found in 15.20% (62/408) of participants. Several G6PD genotypes with newly discovered double missense variants were identified by HRM assays, including G6PD Gaohe + Viangchan, G6PD Valladolid + Viangchan and G6PD Canton + Viangchan. A significantly high frequency of synonymous (c.1311C>T) and intronic (c.1365-13T>C and c.486-34delT) mutations was detected with intermediate to normal enzyme activity. The double missense mutations were less catalytically active than their corresponding single missense mutations, resulting in severe enzyme deficiency. While the mutations had a minor effect on binding affinity, structural instability was a key contributor to the enzyme deficiency observed in G6PD-deficient individuals. Conclusions With varying degrees of enzyme deficiency, G6PD genotyping can be used as a complement to phenotypic screening to identify those who are eligible for 8-aminoquinolines. The information gained from this study could be useful for management and treatment of malaria, as well as for the prevention of unanticipated reactions to certain medications and foods in the studied population.

Journal articles on the topic 'Single radial haemolysis'

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