Protection against rat vaginal candidiasis by adoptive transfer of vaginal B lymphocytes

Efficacy of lipid nanoparticles-based vaccine to protect against vulvovaginal candidiasis (VVC): Implications for women's reproductive health

AIMS

Vulvovaginal candidiasis (VVC) is a common women's health issue, with rising antifungal resistance. This study was aimed to prepare and evaluate the efficacy of a lipid nanoparticle-based vaccine in a murine model of VVC.

MATERIALS AND METHODS

Dried and reconstituted vesicles containing C. albicans antigens (DRNPs-Ca-Ags) vaccine, formulated with phosphatidylcholine and cholesterol-based lipid nanoparticles via film hydration and freeze-drying. The safety evaluation of DRNPs-CaAgs was conducted by determining hepatic (AST, ALT) or renal (BUN, creatinine) biomarkers. Female mice were immunized with DRNPs-CaAgs or Alum-CaAgs, and immune responses were evaluated via antibody titers, IgG isotypes, and splenocyte proliferation. Protective efficacy of vaccine formulations was assessed through fungal burden, biofilm formation, cytokine levels, and histopathological analysis of vaginal tissues.

KEY FINDINGS

Mice vaccinated with DRNPs-CaAgs showed significantly enhanced immune responses, with higher antibody titers and IgG2a levels as compared to the Alum-CaAgs group. Vaginal fungal burden was dramatically reduced (665 ± 78 CFUs in DRNPs-CaAgs immunized group vs. 12,944 ± 3540 CFUs in Alum-CaAgs group, p < 0.01). Biofilm formation decreased by 45 % (p < 0.05), and inflammatory cytokines were significantly lowered. Histopathological analysis revealed minimal tissue damage in DRNPs-CaAgs vaccinated mice.

SIGNIFICANCE

The findings suggest DRNPs-CaAgs as a promising vaccine for VVC, eliciting strong immunity, reducing fungal load, and minimizing inflammation. While the reliance on a murine model is a limitation, future clinical trials are essential to evaluate its efficacy and safety in humans, offering a potential strategy to combat drug-resistant infections and improve women's reproductive health.

Modulatory immune responses in fungal infection associated with organ transplant - advancements, management, and challenges

Organ transplantation stands as a pivotal achievement in modern medicine, offering hope to individuals with end-stage organ diseases. Advancements in immunology led to improved organ transplant survival through the development of immunosuppressants, but this heightened susceptibility to fungal infections with nonspecific symptoms in recipients. This review aims to establish an intricate balance between immune responses and fungal infections in organ transplant recipients. It explores the fundamental immune mechanisms, recent advances in immune response dynamics, and strategies for immune modulation, encompassing responses to fungal infections, immunomodulatory approaches, diagnostics, treatment challenges, and management. Early diagnosis of fungal infections in transplant patients is emphasized with the understanding that innate immune responses could potentially reduce immunosuppression and promise efficient and safe immuno-modulating treatments. Advances in fungal research and genetic influences on immune-fungal interactions are underscored, as well as the potential of single-cell technologies integrated with machine learning for biomarker discovery. This review provides a snapshot of the complex interplay between immune responses and fungal infections in organ transplantation and underscores key research directions.

The fungal quorum-sensing molecule, farnesol, regulates the immune response of vaginal epithelial cells against Candida albicans

BACKGROUND

Farnesol is a Candida-secreted quorum-sensing molecule of great interest as a potential antifungal agent for serious and hardly curable infections-candidiasis, especially vulvovaginal candidiasis (VVC).

METHODS

The effect of farnesol on cellular morphology and viability and evaluated the production of Th1 (IL-2), Th2 (IL-4), proinflammatory (IL-6), chemotactic (IL-8), and Th17 (IL-17) cytokines in the culture supernatants of vaginal epithelial cell line (VK2) were evaluated. Moreover, we tested the inhibitory effect of farnesol on C. albicans adhesion. Scanning electron microscopy was conducted to observe any VK2 cell ultrastructural changes.

RESULTS

Only low concentrations (≤ 50 µmol/L) of farnesol did not affect the morphology and viability of the VK2 cells (P > 0.05). Farnesol reduced the adhesion of C. albicans to the VK2 cells. When treated with farnesol, statistical elevated levels of both IL-4 and IL-17 secreted by the infected VK2 cells were present in the culture supernatants (P < 0.05).

CONCLUSIONS

Farnesol acts as a stimulator to up-regulate the Th17-type innate immune response, as well as Th2-type humoral immunity following C. albicans infection. Further research is required to select the optimal therapeutic dose to develop efficacious and safe mucosal immune adjuvant for treating VVCs.

Fungal infections: Immune defense, immunotherapies and vaccines

Invasive fungal infection is an under recognized and emerging global health threat. Recently, the World Health Organization (WHO) released the first ever list of health-threatening fungi to guide research and public health interventions to strengthen global response to fungi infections and antifungal resistance. Currently, antifungal drugs only demonstrate partial success in improving prognosis of infected patients, and this is compounded by the rapid evolution of drug resistance among fungi species. The increased prevalence of fungal infections in individuals with underlying immunological deficiencies reflects the importance of an intact host immune system in controlling mycoses, and further highlights immunomodulation as a potential new avenue for the treatment of disseminated fungal diseases. In this review, we will summarize how host innate immune cells sense invading fungi through their pattern recognition receptors, and subsequently initiate a series of effector mechanisms and adaptive immune responses to mediate fungal clearance. In addition, we will discuss emerging preclinical and clinical data on antifungal immunotherapies and fungal vaccines which can potentially expand our antifungal armamentarium in future.

Lab-Based Retrospective 10-Year Analysis Shows Seasonal Variation of Vaginal Candida Infection Rates in Belgium

Candida vulvovaginitis is a frequent condition, and although several risk factors are known, its behavior is still enigmatic. The seasonal influence of climate conditions and living habits on its prevalence was studied. In a retrospective lab-based cohort over 10 years, we studied the prevalence of Candida in 12,941 vaginal cultures taken from women attending a vulvovaginitis clinic. The prevalence of non-albicans and albicans species were compared per month to detect differences in positivity rates in summer versus winter months. Chi-square and chi-square for trend were used. Of the 2109 (16.3%) Candida spp. positive swabs, 201 (1.0%) revealed non-albicans species, varying between 1.0% and 2.0% per month, but without significant monthly differences. Over the 10 years, compared to other months, vaginal Candida was more frequent in June (19.0%, p = 0.008) and less frequent in December (14.5%, p = 0.04). The Candida prevalence was 15.5% in summer (June/July/August) versus 14.0% in the winter (Dec/Jan/Feb, p = 0.04). Change in temperature, dietary habits, and bodily adaptations due to increased amount of sunlight were discussed as potential pathophysiological mechanisms to explain the excess of Candida in summertime. Further confirmatory research would be beneficial. Women at risk for Candida vulvovaginitis should pay more attention to living habits in summertime to avoid recurrences.

The Role of B-Cells and Antibodies against Candida Vaccine Antigens in Invasive Candidiasis

Systemic candidiasis is an invasive fungal infection caused by members of the genus Candida. The recent emergence of antifungal drug resistance and increased incidences of infections caused by non-albicans Candida species merit the need for developing immune therapies against Candida infections. Although the role of cellular immune responses in anti-Candida immunity is well established, less is known about the role of humoral immunity against systemic candidiasis. This review summarizes currently available information on humoral immune responses induced by several promising Candida vaccine candidates, which have been identified in the past few decades. The protective antibody and B-cell responses generated by polysaccharide antigens such as mannan, β-glucan, and laminarin, as well as protein antigens like agglutinin-like sequence gene (Als3), secreted aspartyl proteinase (Sap2), heat shock protein (Hsp90), hyphally-regulated protein (Hyr1), hyphal wall protein (Hwp1), enolase (Eno), phospholipase (PLB), pyruvate kinase (Pk), fructose bisphosphate aldolase (Fba1), superoxide dismutase gene (Sod5) and malate dehydrogenase (Mdh1), are outlined. As per studies reviewed, antibodies induced in response to leading Candida vaccine candidates contribute to protection against systemic candidiasis by utilizing a variety of mechanisms such as opsonization, complement fixation, neutralization, biofilm inhibition, direct candidacidal activity, etc. The contributions of B-cells in controlling fungal infections are also discussed. Promising results using anti-Candida monoclonal antibodies for passive antibody therapy reinforces the need for developing antibody-based therapeutics including anti-idiotypic antibodies, single-chain variable fragments, peptide mimotopes, and antibody-derived peptides. Future research involving combinatorial immunotherapies using humanized monoclonal antibodies along with antifungal drugs/cytokines may prove beneficial for treating invasive fungal infections.

Vaccination with Secreted Aspartyl Proteinase 2 Protein from Candida parapsilosis Can Enhance Survival of Mice during C. tropicalis-Mediated Systemic Candidiasis

The rising incidence of non-albicans Candida species globally, along with the emergence of drug resistance, is a cause for concern. This study investigated the protective efficacy of secreted aspartyl proteinase 2 (Sap2) in systemic C. tropicalis infection. Vaccination with recombinant Sap2 (rSap2) protein from C. parapsilosis enhanced survival of mice compared to rSap2 vaccinations from C. albicans (P = 0.02), C. tropicalis (P = 0.06), and sham immunization (P = 0.04). Compared to sham-immunized mice, the fungal CFU number was significantly reduced in organs of Sap2-parapsilosis-immunized mice. Histopathologically, increased neutrophilic recruitment was observed in Sap2-parapsilosis- and Sap2-tropicalis-immunized mice. Among different rSap2 proteins, Sap2-parapsilosis vaccination induced increased titers of Sap2-specific Ig, IgG, and IgM antibodies, which could bind whole fungus. Between different groups, sera from Sap2-parapsilosis-vaccinated mice exhibited increased C. tropicalis biofilm inhibition ability in vitro and enhanced neutrophil-mediated fungal killing. Passive transfer of anti-Sap2-parapsilosis immune serum in naive mice significantly reduced fungal burdens compared to those in mice receiving anti-sham immune serum. Higher numbers of plasma cells and Candida-binding B cells in Sap2-vaccinated mice suggest a role of B cells during early stages of Sap2-mediated immune response. Additionally, increased levels of Th1/Th2/Th17 cytokines observed in Sap2-parapsilosis-vaccinated mice indicate immunomodulatory properties of Sap2. Epitope analysis performed using identified B-cell epitopes provides a basis to understand differences in immunogenicity observed among Sap2-antigens and can aid the development of a multivalent or multiepitope anti-Candida vaccine(s). In summary, our results suggest that Sap2-parapsilosis vaccination can improve mouse survival during C. tropicalis infection by inducing both humoral and cellular immunity, and higher titers of Sap2-induced antibodies are beneficial during systemic candidiasis.

Candida vaginitis: virulence, host response and vaccine prospects

Vulvovaginal candidiasis is a common mucosal infection affecting a large proportion of women with some of them affected by recurrent often intractable forms of the disease. Thus, there is an increasing interest in understanding the pathogenesis of this disease. The aim of our work was to characterize, in animal models of vaginal candidiasis, the components of the host-fungus interaction at the mucosal level.The evidence of an immune response in the vaginal compartment was very encouraging to identify the proper targets for new strategies for vaccination or immunotherapy of vaginal candidiasis. Aspartyl-proteinase (Sap2), which is an important immunodominant antigens and virulence factors of C.albicans acting in mucosal infections, was assembled with virosomes and a vaccine PEV7 was obtained. The results obtained in the mouse model and in the clinical trial conducted by Pevion on women have evidenced that the vaccine PEV7, intravaginally administered, has an encouraging therapeutic potential for the treatment of recurrent vulvovaginal candidiasis. This opens the way to a modality for anti-Candida protection at mucosal level.

Formulation, stability study and preclinical evaluation of a vaginal cream containing curcumin in a rat model of vulvovaginal candidiasis

Owing to the growing resistance among isolates of Candida species to usual antifungal agents and the well-known therapeutic potential of curcumin, the purpose of this study was to develop and validate a vaginal formulation containing this substance and to evaluating its effectiveness in the treatment of experimental vulvovaginal candidiasis. Curcumin was incorporated in a vaginal cream in three concentrations (0.01%, 0.1% and 1.0%). The different concentrations of the cream and its controls were intravaginally administered in an immunosuppressed rat model to evaluate the efficacy in the treatment of experimental vulvovaginal candidiasis. Samples of the cream were also subjected to centrifugation and physical stability tests and an analytical method for quantification of curcumin was validated based on HPLC. The formulation was stable and the HPLC method could be considered suitable for the quantitative determination of curcumin in the cream. After 6 days of preclinical study, the number of infected animals was 1/6 in all groups treated with curcumin vaginal cream and the fungal burden showed a progressive reduction. Reduction in the inflammatory infiltrate was observed in the group treated with 1.0% cream. Vaginal cream containing curcumin could be considered a promising effective antifungal medicine in the treatment of vulvovaginal candidiasis.

Novel Mechanism behind the Immunopathogenesis of Vulvovaginal Candidiasis: "Neutrophil Anergy"

For over 3 decades, investigators have studied the pathogenesis of vulvovaginal candidiasis (VVC) and recurrent VVC (RVVC) through clinical studies and animal models. While there was considerable consensus that susceptibility was not associated with any apparent deficiencies in adaptive immunity, protective immune mechanisms and the role of innate immunity remained elusive. It was not until an innovative live-challenge design was conducted in women that a fuller understanding of the natural history of infection/disease was achieved. These studies revealed that symptomatic infection is associated with recruitment of polymorphonuclear neutrophils (PMNs) into the vaginal lumen. Subsequent studies in the established mouse model demonstrated that infiltrating PMNs were incapable of reducing the fungal burden, which supported the hypothesis that VVC/RVVC was an immunopathology, whereby Candida and the host response drive symptomatic disease. Further studies in mice revealed the requirement for C. albicans hyphae and identified pattern recognition receptors (PRRs) and proinflammatory mediators responsible for the PMN response, all of which are critical pieces of the immunopathogenesis. However, a mechanism explaining PMN dysfunction at the vaginal mucosa remained an enigma. Ultimately, by employing mouse strains resistant or susceptible to chronic VVC, it was determined that heparan sulfate (HS) in the vaginal environment of susceptible mice serves as a competitive ligand for Mac-1 on PMNs, which effectively renders the PMNs incapable of binding to Candida to initiate killing. Hence, the outcome of symptomatic VVC/RVVC is postulated to be dependent on a PMN-mediated immunopathogenic response involving HS that effectively places the neutrophils in a state of functional anergy.

Recurrent Vulvovaginal Candidiasis: Could It Be Related to Cell-Mediated Immunity Defect in Response to Candida Antigen?

BACKGROUND

Recurrent vulvovaginal candidiasis (RVVC) is a common cause of morbidity affecting millions of women worldwide. Patients with RVVC are thought to have an underlying immunologic defect. This study has been established to evaluate cell-mediated immunity defect in response to candida antigen in RVVC cases.

MATERIALS AND METHODS

Our cross-sectional study was performed in 3 groups of RVVC patients (cases), healthy individuals (control I) and known cases of chronic mucocutaneous candidiasis (CMC) (control II). Patients who met the inclusion criteria of RVVC were selected consecutively and were allocated in the case group. Peripheral blood mononuclear cells were isolated and labeled with CFSE and proliferation rate was measured in exposure to candida antigen via flow cytometry.

RESULTS

T lymphocyte proliferation in response to candida was significantly lower in RVVC cases (n=24) and CMC patients (n=7) compared to healthy individuals (n=20, <0.001), but no statistically significant difference was seen between cases and control II group (P>0.05). Family history of primary immunodeficiency diseases (PID) differed significantly among groups (P=0.01), RVVC patients has family history of PID more than control I (29.2 vs. 0%, P=0.008) but not statistically different from CMC patients (29.2 vs. 42.9%, P>0.05). Prevalence of atopy was greater in RVVC cases compared to healthy individuals (41.3 vs. 15%, P=0.054). Lymphoproliferative activity and vaginal symptoms were significantly different among RVVC cases with and without allergy (P=0.01, P=0.02).

CONCLUSION

Our findings revealed that T cells do not actively proliferate in response to Candida antigen in some RVVC cases. So it is concluded that patients with cell-mediated immunity defect are more susceptible to recurrent fungal infections of vulva and vagina. Nonetheless, some other cases of RVVC showed normal function of T cells. Further evaluations showed that these patients suffer from atopy. It is hypothesized that higher frequency of VVC in patients with history of atopy might be due to allergic response in mucocutaneous membranes rather than a functional impairment in immune system components.

Studies of Immune Responses in Candida vaginitis

The widespread occurrence of vaginal candidiasis and the development of resistance against anti-fungal agents has stimulated interest in understanding the pathogenesis of this disease. The aim of our work was to characterize, in an animal model of vaginal candidiasis, the mechanisms that play a role in the induction of mucosal immunity against C. albicans and the interaction between innate and adaptive immunity. Our studies evidenced the elicitation of cell-mediated immunity (CMIs) and antibody (Abs)-mediated immunity with a Th1 protective immunity. An immune response of this magnitude in the vagina was very encouraging to identify the proper targets for new strategies for vaccination or immunotherapy of vaginal candidiasis. Overall, our data provide clear evidence that it is possible to prevent C. albicans vaginal infection by active intravaginal immunization with aspartyl proteinase expressed as recombinant protein. This opens the way to a modality for anti-Candida protection at the mucosa. The recombinant protein Sap2 was assembled with virosomes, and a vaccine PEVION7 (PEV7) was obtained. The results have given evidence that the vaccine, constituted of virosomes and Secretory aspartyl proteinase 2 (Sap2) (PEV7), has an encouraging therapeutic potential for the treatment of recurrent vulvovaginal candidiasis.

Immunological basis of anti-Candida vaccines focused on synthetically prepared cell wall mannan-derived manno-oligomers

The increasing incidence of diseases caused by Candida species and complications in individuals with impaired immunity require new strategies for candidiasis treatment and prevention. The available therapies are often of limited effectiveness in immunocompromised patients, resulting in treatment failures, chronic infections and high mortality rates. Research directed at identifying the composition of an effective vaccine is required. Mannan forms the outermost layer of the Candida cell wall and has an essential role in modulation of anti-Candida host immune responses. Therefore, Candida cell wall mannan and synthetically prepared manno-oligomer-based glycoconjugates are the foci of attention in vaccine candidate development. Almost all of the existing human vaccines mediate protection through neutralizing antibodies. Th1-based and/or Th17-based cellular immune responses, rather than antibody-mediated immunity, mediate protection against candidiasis. Findings of published studies indicate that analysis of cellular immune responses as well as antibody responses is necessary when assessing the immunomodulatory properties of manno-oligomer-based glycoconjugates that are potential anti-Candida vaccine candidates.

Transcriptomic analysis of vulvovaginal candidiasis identifies a role for the NLRP3 inflammasome

Treatment of vulvovaginal candidiasis (VVC), caused most frequently by Candida albicans, represents a significant unmet clinical need. C. albicans, as both a commensal and a pathogenic organism, has a complex and poorly understood interaction with the vaginal environment. Understanding the complex nature of this relationship is necessary for the development of desperately needed therapies to treat symptomatic infection. Using transcriptome sequencing (RNA-seq), we characterized the early murine vaginal and fungal transcriptomes of the organism during VVC. Network analysis of host genes that were differentially expressed between infected and naive mice predicted the activation or repression of several signaling pathways that have not been previously associated with VVC, including NLRP3 inflammasome activation. Intravaginal challenge of Nlrp3(-/-) mice with C. albicans demonstrated severely reduced levels of polymorphonuclear leukocytes (PMNs), alarmins, and inflammatory cytokines, including interleukin-1β (IL-1β) (the hallmarks of VVC immunopathogenesis) in vaginal lavage fluid. Intravaginal administration of wild-type (WT) mice with glyburide, a potent inhibitor of the NLRP3 inflammasome, reduced PMN infiltration and IL-1β to levels comparable to those observed in Nlrp3(-/-) mice. Furthermore, RNA-seq analysis of C. albicans genes indicated robust expression of hypha-associated secreted aspartyl proteinases 4, 5, and 6 (SAP4-6), which are known inflammasome activators. Despite colonization similar to that of the WT strain, ΔSAP4-6 triple and ΔSAP5 single mutants induced significantly less PMN influx and IL-1β during intravaginal challenge. Our findings demonstrate a novel role for the inflammasome in the immunopathogenesis of VVC and implicate the hypha-associated SAPs as major C. albicans virulence determinants during vulvovaginal candidiasis.

IMPORTANCE

Vaginitis, most commonly caused by the fungus Candida albicans, results in significant quality-of-life issues for all women of reproductive age. Recent efforts have suggested that vaginitis results from an immunopathological response governed by host innate immunity, although an explanatory mechanism has remained undefined. Using comprehensive genomic, immunological, and pharmacological approaches, we have elucidated the NLRP3 inflammasome as a crucial molecular mechanism contributing to host immunopathology. We have also demonstrated that C. albicans hypha-associated secreted aspartyl proteinases (SAP4-6 and SAP5, more specifically) contribute to disease immunopathology. Ultimately, this study enhances our understanding of the complex interplay between host and fungus at the vaginal mucosa and provides proof-of-principle evidence for therapeutic targeting of inflammasomes for symptomatic vulvovaginal candidiasis.

New approaches in the development of a vaccine for mucosal candidiasis: progress and challenges

The commensal fungus Candida albicans causes mucosal candidiasis in the rapidly expanding number of immunocompromised patients. Mucosal candidiasis includes oropharyngeal, esophageal, gastrointestinal, and vaginal infections. Vulvovaginal candidiasis (VVC) and antimycotic-refractory recurrent VVC is a frequent problem in healthy childbearing women. Both these mucosal infections can affect the quality of life and finding new therapeutical and preventive approaches is a challenge. A vaccine against candidal infections would be a new important tool to prevent and/or cure mucosal candidiasis and would be of benefit to many patients. Several Candida antigens have been proposed as vaccine candidates including cell wall components and virulence factors. Here we discuss the recent progress and problems associated with vaccination against mucosal candidiasis.

Cytokines in the host response to Candida vaginitis: Identifying a role for non-classical immune mediators, S100 alarmins

Vulvovaginal candidiasis (VVC), caused by Candida albicans, affects a significant number of women during their reproductive years. More than two decades of research have been focused on the mechanisms associated with susceptibility or resistance to symptomatic infection. Adaptive immunity by Th1-type CD4(+) T cells and downstream cytokine responses are considered the predominant host defense mechanisms against mucosal Candida infections. However, numerous clinical and animal studies have indicated no or limited protective role of cells and cytokines of the Th1 or Th2 lineage against vaginal infection. The role for Th17 is only now begun to be investigated in-depth for VVC with results already showing significant controversy. On the other hand, a clinical live-challenge study and an established animal model have shown that a symptomatic condition is intimately associated with the vaginal infiltration of polymorphonuclear leukocytes (PMNs) but with no effect on vaginal fungal burden. Subsequent studies identified S100A8 and S100A9 alarmins as key chemotactic mediators of the acute PMN response. These chemotactic danger signals appear to be secreted by vaginal epithelial cells upon interaction and early adherence of Candida. Thus, instead of a putative immunodeficiency against Candida involving classical immune cells and cytokines of the adaptive response, the pathological inflammation in VVC is now considered a consequence of a non-productive innate response initiated by non-classical immune mediators.

Prospects for development of a vaccine to prevent and control vaginal candidiasis

A vaccine against recurrent vulvovaginal candidiasis (RVVC) would benefit a large number of women who suffer from this debilitating syndrome. To date, several antigen formulations have been tested with modest results. In this article, we review the latest vaccine study reported in the literature. The candidate is a β-glucan conjugate administered with a human compatible adjuvant. Results in a mouse model of vaginitis were again modest for protection. However, the study included live animal imaging to quantify fungal burden; animals were challenged with a Candida strain carrying a gene encoding a glycophosphatidylinositol (GPI)-linked cell wall protein and luciferase. Fungal burden was expressed as photons following substrate administration. Protection appeared to be mediated by β-glucan antibodies. Although modest protection was observed, the imaging system was less variable than semi-quantitative plate counts of vaginal lavage fluid. Despite these advances in evaluating protection, a vaccine candidate against RVVC worthy of clinical testing remains elusive.

A highly immunogenic recombinant and truncated protein of the secreted aspartic proteases family (rSap2t) of Candida albicans as a mucosal anticandidal vaccine

Sap2 (secreted aspartyl proteinase2) is a member of the Sap family of Candida albicans, a human opportunistic pathogen, which acts as a virulence factor in experimental animal models of mucosal candidiasis. The C. albicans SAP2 was subcloned into vector pDS56-RBSII-6xhis, under the control of an inducible promoter to produce a truncated 6xhis-tagged, enzymatically inactive Sap2, lacking the N-terminus 76 amino acids (rSap2t). This recombinant protein was purified to homogeneity by one-step nickel-chelate affinity chromatography and used to immunize intravaginally oophorectomized estradiol-treated rats. These animals raised local anti-rSap2t immunoglobulin G (IgG) and IgA antibodies and were protected from the challenge of a highly vaginopathic strain of the fungus. Protection was possibly due to the specific antibodies as suggested by the passive transfer of immune vaginal fluid and the protective effects of passive vaccination with anti-rSap2t IgM and IgG monoclonal antibodies. Hence, this new recombinant proteinase constitutes a novel tool to investigate mechanisms of anti-Candida protection at the vaginal level and as vaccination against vaginal candidiasis, a common, frequently recurrent and sometimes antimycotic-refractory infection in women.