Добірка наукової літератури з теми "Vaginal immunization"

ABSTRACT This investigation evaluated immunity to vaginal herpes simplex virus type 2 (HSV-2) infection after local or parenteral immunization with attenuated HSV-2. Vaginal immunization induced sterilizing immunity against challenge with a high dose of wild-type virus, whereas parenteral immunizations protected against neurologic disease but did not entirely prevent infection of the vagina. Vaginal immunization caused 86- and 31-fold increases in the numbers of immunoglobulin G (IgG) plasma cells in the vagina at 6 weeks and 10 months after immunization, whereas parenteral immunizations did not increase plasma cell numbers in the vagina. Vaginal secretion/serum titer ratios and specific antibody activities in vaginal secretions and serum indicated that IgG viral antibody was produced in the vagina and released into vaginal secretions at 6 weeks and 10 months after vaginal immunization but not after parenteral immunizations. In contrast to the case for plasma cells, the numbers of T and B lymphocytes in the vagina were similar in vaginally and parenterally immunized mice. Also, lymphocyte numbers in the vagina were markedly but similarly increased by vaginal challenge with HSV-2 in both vaginally and parenterally immunized mice. Lymphocyte recruitment to the vagina after virus challenge appeared to involve memory lymphocytes, because it was not observed in nonimmunized mice. Thus, local vaginal immunization with attenuated HSV-2 increased the number of IgG plasma cells in the vagina and increased vaginal secretion/serum titer ratios to 3.0- to 4.7-fold higher than in parenterally immunized groups but caused little if any selective homing of T and B lymphocytes to the vagina.

ABSTRACT We studied the antibody response including antibody-secreting cells (ASC) in the female genital tract of mice after mucosal immunizations with the recombinant B subunit of cholera toxin (rCTB) perorally, intraperitoneally, vaginally, and intranasally (i.n.). The strongest genital antibody responses as measured with a novel perfusion-extraction method were induced after vaginal and i.n. immunizations, and these routes also gave rise to specific immunoglobulin A (IgA) and IgG ASC in the genital mucosa. Specific ASC in the iliac lymph nodes, which drain the female genital tract, were seen only after vaginal immunization. Progesterone treatment increased the ASC response in the genital tissue after all mucosal immunizations but most markedly after vaginal immunization. We also tested rCTB as a carrier for human gamma globulin (HGG) and the effect of adding cholera toxin (CT) as an adjuvant for the induction of systemic and genital antibody responses to HGG after vaginal and i.n. immunizations. Vaginal immunizations with HGG conjugated to rCTB resulted in high levels of genital anti-HGG antibodies whether or not CT was added, while after i.n. immunization the strongest antibody response was seen with the conjugate together with CT. In summary, vaginal and i.n. immunization give rise to a specific mucosal immune response including ASC in the genital tissue, and vaginal immunization also elicits ASC in the iliac lymph nodes. We have also shown that rCTB can act as an efficient carrier for a conjugated antigen for induction of a specific antibody response in the genital tract of mice after vaginal or i.n. immunization.

Abstract Uterine and vaginal secretions collected from intact adult female rats were analyzed to determine whether immunization at sites distal to the reproductive tract had any effect on the presence of specific IgA and IgG antibodies in genital tract secretions. Peyer's patch and i.p. immunization and boost with sheep red blood cells (SRBC) stimulated the appearance of specific IgA antibodies in uterine and vaginal secretions of uterine-ligated animals. IgG antibodies were also induced in uterine but not in vaginal secretions. In contrast, subcutaneous immunization and boost elicited a weak IgA uterine and IgG vaginal response. To establish the role of estradiol in regulating the presence of specific antibodies in the female genital tract, ovariectomized rats received primary and/or secondary Peyer's patch immunizations with hormone treatment. Administration of estradiol daily for 3 days before sacrifice resulted in a significant accumulation of IgA and IgG antibodies to SRBC in uterine secretions. In the absence of estradiol, antibody content was negligible. Vaginal antibody levels were also clearly influenced by estradiol. In contrast to the uterus, however, specific IgA and IgG antibodies were present in the vaginal secretions of saline-injected immunized animals and were markedly inhibited in animals treated with estradiol. These results indicate that antibodies in genital tract secretions can be induced by immunization of the Peyer's patches and that their presence in uterine secretions is clearly dependent on estradiol. Further, they indicate that gut-derived specific antibodies enter the vagina in the absence of hormone stimulation and that estradiol exerts an inhibitory effect on their presence in vaginal secretions.

ABSTRACT To determine optimal strategies to induce specific-antibody-secreting cells (specific ASC) in the rectal and vaginal mucosae, we immunized monkeys with a prototype mucosal immunogen, cholera toxin (CT), given locally or via gastric or parenteral administration. Repeated rectal or vaginal CT immunizations induced strong mucosal and systemic ASC responses. The mucosal responses were, however, confined to the immunization sites and comprised high levels of both specific antitoxin immunoglobulin A (IgA) and IgG. Large numbers of specific IgA and IgG ASC were detected in cell suspensions from dissociated genital and rectal tissues, demonstrating local accumulation of effector B cells at these sites. Intragastric immunization with CT did not per se give rise to cervicovaginal or rectal ASC responses but did prime for a rectal IgA ASC response to local booster immunization. Both rectal and vaginal immunizations also induced circulating blood IgG ASC and IgA ASC. In conclusion, these results show that local administration of antigen to the rectal or vaginal mucosa results in higher ASC responses than systemic or distant mucosal delivery. Furthermore, both the vaginal and the rectal mucosae can serve as inductive sites for systemic ASC responses. These observations should be relevant to the development of vaccines against sexually transmitted diseases such as that caused by human immunodeficiency virus.

ABSTRACT Vaccines are being sought for contraception and the prevention of sexually transmitted diseases. However, progress is slow in this area largely because of lack of information on induction of protective immune responses in genital tract mucosa. In this study, we investigated whether in vivo transfection with a model DNA-based antigen delivered by gene gun technology would induce an antibody response detectable in vaginal secretions. Female rats were immunized with plasmids encoding human growth hormone (HGH) under the control of a cytomegalovirus promoter (pCMV/HGH) via vaginal mucosa (V), Peyer’s patch (PP), and/or abdominal skin (S) routes. Localization of HGH in the target tissues demonstrated that all three sites can be transfected in vivo with pCMV/HGH. Vaginal tissues expressed roughly the same level of plasmid as skin. Antibodies to HGH were detectable in serum and vaginal secretions in rats immunized with pCMV/HGH. In the rats primed and boosted vaginally, vaginal immunoglobulin A (IgA) and IgG antibody titers to HGH were sustained for at least 14 weeks, whereas rats immunized via other routes and protocols (S/V, S/S, PP/PP, or PP/V) did not consistently sustain significant vaginal antibody titers beyond week 6. DNA-based immunizations administered by the gene gun may be an effective method of inducing local immunity in the female genital tract.

Abstract It is widely believed that primary immune induction in type-II mucosa (vagina, mouth & cornea) occurs in the draining LNs due to a lack of mucosa-associated lymphoid tissue. In this process, naïve T cells located in the draining LNs are primed by antigen (Ag)-bearing dendritic cells migrating from the Ag-exposed mucosa. Primed T cells then travel to the mucosal site through the bloodstream. In contrast to this paradigm, we show that vaginal mucosa itself can act as an immune inductive site for generation of primary CD8+ T cell mucosal immunity. As evidence, we found that naïve CD8+ T cells routinely migrated to the female reproductive tract and that Ag-specific CD8+ T cells could be generated in the LN-deficient mice after intravaginal immunization. Further, the adoptively transferred naïve OT-1 CD8+ T cells were activated in the vaginal mucosa but not in the draining LNs at 24 hours after intravaginal immunization, even in the presence of FTY720, a drug blocking the egress of T cells from LNs. In addition, the Ag-bearing cells isolated from immunized vaginal mucosa were able to stimulate naïve TCR-transgenic RT-1 CD8+ T cells to secret IFN-γ and undergo proliferation. Finally, vaginal mucosa largely supported the expansion of Ag-specific CD8+ T cells. In conclusion, we present evidence for a new paradigm for primary CD8+ T cell immune induction in type-II mucosa of the vagina, one that occurs locally without the help of draining LNs or mucosa-associated lymphoid tissue.

Abstract Humoral immunity, especially at mucosal sites, is important for preventing HIV acquisition. Replicating adenovirus (Ad)-SIV priming/gp120 boosting regimens have elicited mucosal immunity and protection against intrarectal SIV challenge in Rhesus macaques. Here we investigated mucosal responses in female macaques primed intranasally/orally, then intratracheally with Ad5hr-SIV(Env/gag/nef), boosted twice intramuscularly with SIV gp120, and challenged vaginally with repeated low-dose SIVmac251. Vaginal washes and rectal swabs and biopsies were obtained 3-weeks post-immunizations. gp120-specific antibodies were assayed by ELISA and memory B-cells by flow cytometry. Gp120-specific rectal memory B-cells increased post-Ad priming but waned post-boosting, whereas rectal and vaginal antibodies increased post-boosting. Compared to pre levels, rectal gp120-specific IgA (p = 0.011) and IgG (p< 0.0001) were elevated post-2nd boost; vaginal IgA/IgG antibodies differed post-1st boost (both p<0.0001) and IgG levels > IgA post-2nd boost (p=0.001). Rectal memory B cells post- 1st and 2nd Ads positively correlated with gp120-specific rectal IgA (p = 0.015, p = 0.0013, respectively) post-1st Ad, indicating vaccine targeting to mucosal effector sites. Significantly delayed SIV acquisition was not seen, but vaginal IgG post-1st Ad correlated with number of challenges (p=0.029). Vaccinated animals had lower acute viremia than controls (p = 0.054), consistent with higher vaginal gp120-specific IgG 2 weeks post-infection (p < 0.0001). Our data show that upper respiratory tract immunization with replicating Ad vectors elicits strong mucosal immunity with potential protective efficacy against rectal/genital transmission.

Immunizations are cost-effective measures for assuring public health. However, recent outbreaks of measles, mumps, and pertussis underscore the inadequacy of current immunization programs. A model identifying those children who are likely to be inadequately immunized could focus the use of limited health funds. A retrospective examination of the medical charts of 101 children in a large inner-city clinic was undertaken to determine if specific factors were associated with inadequate immunization status. Fifty percent of the children were inadequately immunized by 18 months of age (no measles-mumps-rubella or fewer than three diphtheria-pertussis-tetanus vaccinations). Logistic regression analyses showed that older maternal age, no recurrent or chronic illnesses, and vaginal delivery were independently associated with inadequate immunization status. However, on many charts, information on maternal, social, and environmental variables was incomplete. The increasing use of structured medical charts will enhance data collection and the determination of an appropriate index. A prospective study of the variables identified, along with standardization of medical records and inclusion of social history data, is necessary to further investigate the utility of screening criteria for inadequate immunizations.

The ability to prime the immune system against an antigen, and to rapidly recall this response upon antigen reencounter is a fundamental characteristic of the adaptive immune response. The association of an antigen recognized by the immune system in a certain tissue, with the same antigen encountered at a later timepoint in a different tissue, is of primary importance to obtain a systemic and effective immune response and is the foundation behind the utilization of vaccines. The study of vaccine delivery platforms that may activate the immune system in such a manner is therefore of primary importance in the effort to design novel vaccine formulation and prime-boost strategies. The aim of the present work was to study the in vivo priming effect induced by a recombinant Streptococcus gordonii vaccine vector expressing a heterologous antigen and delivered to the vaginal tract, a unique mucosal tissue. To study the priming effect induced by the recombinant Streptococcus gordonii, we employed a prime-boost strategy and compared the cellular an humoral immune response towards the soluble antigen between recombinant- and WT-immunized mice. Using this model, we show that vaginal immunization with the recombinant Streptococcus gordonii elicited systemic production of antigen-specific antibodies, shifted the IgG subclasses profile, led to an increase in plasma cells in the lymph nodes, a higher number of antigen-specific antibody-secreting cells in the spleen and modulated the cytokine expression profile of splenocytes. The longevity of the priming effect induced by the recombinant vector was also analyzed by comparing three and six months boosting schedules. We found that the priming is boostable with a similar efficacy for at least six months (Chapter 3). These data demonstrate that vaginal priming with the recombinant S. gordonii vector results in a systemic activation of both cellular and humoral immune compartments, and that this priming effect is long-lived without significant immune waning. In this study, we also assessed the transcriptomic response of splenocytes from S. gordonii-immunized mice towards the antigen. We observed differences in immune pathways between recombinant- and WT-immunized mice, and also between the three- and six-months boosted groups (Chapter 4). In addition, we observed a gene signature correlated with antigen-specific IgG titers. These findings suggest that the immune system’s encounter with the antigen on the surface of the recombinant S. gordonii in the vaginal tract results in a differential immune activation in in response to the antigen. This work contributes to the knowledge on the capability of recombinant live vaccine vectors delivered mucosally to prime and modulate the immune response, and has important implications in the design of innovative vaccination strategies.

L’avènement des multi-thérapies antirétrovirales a permis une réduction importante de la mortalité associée au VIH en induisant notamment la chute de la charge virale à moins de 50 copies/mL et une récupération progressive du nombre de lymphocytes T CD4+ (LT-CD4). Cependant, certains patients définis comme mauvais répondeurs immunologiques (MRI) ne parviennent pas à récupérer un taux de CD4 généralement considéré comme « protecteur » (>500cellules/µL). L’interleukine-7 (IL-7), cytokine essentielle à la thymopoïèse et à l’homéostasie lymphocytaire T, a été utilisée en étude clinique afin de restaurer et maintenir le taux de LT-CD4 chez les patients MRI. La première partie de mon travail de thèse visait à évaluer l’impact d’une telle thérapie sur le réservoir viral circulant. Dans l’essai clinique sur lequel nous avons travaillé (INSPIRE 3, Cytheris), des cycles d’administration d’IL-7 ont induit une augmentation significative du nombre de LT-CD4 et CD8 circulants, avec une expansion majoritaire des populations naïves et centrales mémoires. Nous avons montré qu’un cycle d’injections d’IL-7 induisait une augmentation significative de la quantité de cellules infectées circulantes 28 jours et 3 mois post-injection. Cependant, malgré l’accroissement de la fréquence de LT-CD4 infectés 28 jours post-injection, nous avons observé une diminution significative de la charge virale ADN par million de LT-CD4 chez la majorité des patients 3 mois après l’initiation de la thérapie, suggérant une élimination partielle de cellules infectées. Suite au second cycle d’injections, nous n’avons pas observé d’évolution de la quantité de cellules infectées circulantes ni de la fréquence de LT-CD4 infectés, suggérant un impact différent des 2 cycles d’injections sur la dynamique du réservoir viral périphérique. Enfin, certains patients ayant développé des anticorps neutralisants anti-IL-7 (Nab) suite au second cycle d’injections d’IL-7, nous avons cherché à identifier des facteurs prédictifs de l’apparition de ces anticorps ainsi que leurs conséquences physiologiques in vivo. Le seul paramètre caractérisant ces patients est l’amplitude de la reconstitution T-CD4 au cours du premier cycle d’injections d’IL-7. Il semble donc qu’une meilleure réponse à l’IL-7 ait pour conséquence de faciliter le développement de la réponse immune contre cette cytokine. Cependant, ces anticorps ne sont détectables que de façon transitoire chez les patients. De plus, nous avons observé une diminution significative, mais transitoire, de la prolifération des thymocytes chez les patients présentant des Nab, démontrant un impact fonctionnel de ces anticorps sur l’activité biologique de l’IL-7 endogène. L’injection systémique d’IL-7 induit la migration des cellules circulantes vers différents compartiments tissulaires lymphoïdes et non lymphoïdes. Dans une seconde partie de mon travail de thèse, j’ai étudié le pouvoir adjuvant de cette cytokine administrée localement par pulvérisation à la surface de la muqueuse vaginale. Dans le modèle macaque rhésus, nous avons mis en évidence une augmentation de la production d’un large spectre de chimiokines dans le chorion et l’épithélium vaginal des animaux 48 heures après l’administration vaginale d’IL-7. Cette surexpression de chimiokines s’accompagne d’une migration massive de LT-CD4, CD8, macrophages, cellules dendritiques et cellules NK dans cette muqueuse, suggérant l’augmentation de la vigilance immunologique. L’effet adjuvant de cette cytokine a été confirmé par l’analyse de la réponse humorale muqueuse de macaques vaccinés par pulvérisation vaginale d’antigènes 48h après l’administration du spray d’IL-7. Dans les lavages cervicovaginaux (CVL) des animaux traités à l’IL-7, nous avons mis en évidence des réponses spécifiques de type IgA et IgG plus rapides, plus fortes et plus durables que chez les animaux contrôles, démontrant la capacité de l’IL-7 à préparer la muqueuse vaginale à répondre à une stimulation antigénique locale
Highly Active Antiretroviral Therapy (HAART) has led to significant reduction of HIV-associated mortality by maintaining an undetectable viral load and inducing progressive CD4-T cell restoration. However, some patients, defined as poor immunological responders (PIR), fail to restore their CD4 counts to 500cells/µL during treatment, a threshold considered as the protective against AIDS related or non AIDS related malignancies, opportunistic infections and cardiovascular events. Interleukin-7 (IL-7), an essential cytokine for thymopoïesis and T cell homeostasis has been used in clinical trials aimed at restoring and maintaining CD4 counts in PIR patients. The first part of my thesis project aimed at assessing the impact of IL-7 therapy on circulating HIV reservoir. In the clinical study we worked on (INSPIRE 3, Cytheris), cycles of IL-7 injections led to a significant increase of the number of circulating CD4 and CD8 T-cells, with a predominance of naïve and central memory T cell expansion. We have shown that one cycle of IL-7 injections induced a significant increase in the number of circulating infected cells 28 days and 3 months post-injections. However, despite a significant increase in the frequency of infected CD4 T-cells 28 days post-injections, we observed a significant decrease of HIV-DNA load in CD4 T-cells in the majority of patients 3 months after the therapy initiation. These data suggest a partial elimination of HIV infected cells. After the second cycle of IL-7 injections, we did not observed any change in the number or frequency of circulating infected cells, suggesting a differential impact of the two IL-7 injection cycles on the dynamics of circulating HIV-reservoir. Finally, considering that some patients developed anti-IL-7 neutralizing antibodies (Nab) after the second cycle of IL-7 injections, we looked for predictive factors of this immunogenicity and analyzed its physiological consequences in vivo. The only parameter that distinguished Nab and non-Nab patients was the extent of CD4 T-cell reconstitution during the first cycle of therapy. This suggests that a better response to IL-7 also facilitates the development of auto-antibodies to the cytokine. However, these antibodies were only transiently detectable after the second cycle of therapy. Moreover, the appearance of Nab was associated with a significant but transient decrease of thymocyte proliferation, suggesting a functional impact of these antibodies on the endogenous IL-7 function. Systemic injection of IL-7 induces circulating T cells homing from the blood into lymphoid and non-lymphoid tissues. In the second part of my thesis project, I evaluated whether this cytokine could be used as an adjuvant when sprayed on the vaginal mucosa. Ten micrograms of IL-7 directly sprayed in the vaginal tract of rhesus monkeys induced, 48h after administration, the production of a large pattern of chemokines in the vaginal chorion and epithelium. This chemokine expression was accompanied by massive homing of CD4 and CD8-T cells, macrophages, dendritic cells and NK cells in the vaginal mucosa, suggesting an increased immunological vigilance. Finally, the adjuvant potential of this cytokine was confirmed by analyzing local humoral immune response after vaginal administration of antigens 48h following IL-7 spray. In cervicovaginal washes (CVL) of treated animals, we observed a faster, stronger and longer-lasting specific IgA and IgG response than in control animals, highlighting the capacity of IL-7 to prepare the vaginal mucosa response to local antigen stimulation

Until very recently, the discussion about infections in pregnancy was focused on specific microorganisms, how the pregnant mother acquired the organism and transmitted it to the fetus, the effects of the infection on fetal survival, fetal loss, fetal growth, and development, and on the long-term sequelae. The narrative applied to the ‘TORCHES’ group of infections namely toxoplasmosis, rubella, cytomegalovirus, herpes, and syphilis, dominated the scene before the emergence of newer perinatal infections such as parvovirus B19 and HIV in the later years of the twentieth century. Numerically, the TORCHES group of infections accounts for fewer perinatal complications and morbidity than the more common but less specific ascending subclinical infections encountered clinically as chorioamnionitis and its precursors such as bacterial vaginosis, intermediate vaginal flora, aerobic vaginitis, group B streptococci, and other variants of abnormal lower genital tract flora. The contribution of ascending subclinical infections to the incidence of preterm delivery, long-term neurological and respiratory morbidity, and exacerbation of intrapartum hypoxic ischaemic injury is grossly understated worldwide while disproportionate amounts of resources continue to be expended globally on screening for and the management of the TORCHES group and related infections. In this chapter, the authors aim to cover the common and important perinatal infections and attempt to redress the imbalance in emphasis by drawing attention to the role of ascending subclinical infections in the aetiology of major adverse perinatal outcomes such as brain injury in both the term and the preterm infant.