History and new insights into host defense against vaginal candidiasis

Antimicrobial Properties of Capsaicin: Available Data and Future Research Perspectives

Capsaicin is a phytochemical derived from plants of the genus Capsicum and subject of intensive phytochemical research due to its numerous physiological and therapeutical effects, including its important antimicrobial properties. Depending on the concentration and the strain of the bacterium, capsaicin can exert either bacteriostatic or even bactericidal effects against a wide range of both Gram-positive and Gram-negative bacteria, while in certain cases it can reduce their pathogenicity by a variety of mechanisms such as mitigating the release of toxins or inhibiting biofilm formation. Likewise, capsaicin has been shown to be effective against fungal pathogens, particularly Candida spp., where it once again interferes with biofilm formation. The parasites Toxoplasma gondi and Trypanosoma cruzi have been found to be susceptible to the action of this compound too while there are also viruses whose invasiveness is significantly dampened by it. Among the most encouraging findings are the prospects for future development, especially using new formulations and drug delivery mechanisms. Finally, the influence of capsaicin in somatostatin and substance P secretion and action, offers an interesting array of possibilities given that these physiologically secreted compounds modulate inflammation and immune response to a significant extent.

Kaempferol: Antimicrobial Properties, Sources, Clinical, and Traditional Applications

Flavonoids are a category of plant-derived compounds which exhibit a large number of health-related effects. One of the most well-known and studied flavonoids is kaempferol, which can be found in a wide variety of herbs and plant families. Apart from their anticarcinogenic and anti-inflammatory effects, kaempferol and its associated compounds also exhibit antibacterial, antifungal, and antiprotozoal activities. The development of drugs and treatment schemes based on these compounds is becoming increasingly important in the face of emerging resistance of numerous pathogens as well as complex molecular interactions between various drug therapies. In addition, many of the kaempferol-containing plants are used in traditional systems all over the world for centuries to treat numerous conditions. Due to its variety of sources and associated compounds, some molecular mechanisms of kaempferol antimicrobial activity are well known while others are still under analysis. This paper thoroughly documents the vegetal and food sources of kaempferol as well as the most recent and significant studies regarding its antimicrobial applications.

Role of Vaginal Mucosa, Host Immunity and Microbiota in Vulvovaginal Candidiasis

Vulvovaginal candidiasis (VVC) is a prevalent gynaecological disease characterised by vaginal wall inflammation that is caused by Candida species. VVC impacts almost three-quarters of all women throughout their reproductive years. As the vaginal mucosa is the first point of contact with microbes, vaginal epithelial cells are the first line of defence against opportunistic Candida infection by providing a physical barrier and mounting immunological responses. The mechanisms of defence against this infection are displayed through the rapid shedding of epithelial cells, the presence of pattern recognition receptors, and the release of inflammatory cytokines. The bacterial microbiota within the mucosal layer presents another form of defence mechanism within the vagina through acidic pH regulation, the release of antifungal peptides and physiological control against dysbiosis. The significant role of the microbiota in maintaining vaginal health promotes its application as one of the potential treatment modalities against VVC with the hope of alleviating the burden of VVC, especially the recurrent disease. This review discusses and summarises current progress in understanding the role of vaginal mucosa and host immunity upon infection, together with the function of vaginal microbiota in VVC.

It Takes Two to Tango: How a Dysregulation of the Innate Immunity, Coupled With Candida Virulence, Triggers VVC Onset

Vulvovaginal candidiasis (VVC) is a symptomatic inflammation of the vagina mainly caused by C. albicans. Other species, such as C. parapsilosis, C. glabrata, C. tropicalis, and C. krusei, are mainly associated to the recurrent form of the disease (RVVC), although with a lower frequency. In its yeast form, C. albicans is tolerated by the vaginal epithelium, but switching to the invasive hyphal form, co-regulated with the expression of genes encoding virulence factors such as secreted aspartyl proteases (Sap) and candidalysin, allows for tissue damage. Vaginal epithelial cells play an important role by impairing C. albicans tissue invasion through several mechanisms such as epithelial shedding, secretion of mucin and strong interepithelial cell connections. However, morphotype switching coupled to increasing of the fungal burden can overcome the tolerance threshold and trigger an intense inflammatory response. Pathological inflammation is believed to be facilitated by an altered vaginal microbiome, i.e., Lactobacillus dysbiosis. Notwithstanding the damage caused by the fungus itself, the host response to the fungus plays an important role in the onset of VVC, exacerbating fungal-mediated damage. This response can be triggered by host PRR-fungal PAMP interaction and other more complex mechanisms (i.e., Sap-mediated NLRP3 activation and candidalysin), ultimately leading to strong neutrophil recruitment. However, recruited neutrophils appear to be ineffective at reducing fungal burden and invasion; therefore, they seem to contribute more to the symptoms associated with vaginitis than to protection against the disease. Recently, two aspects of the vulvovaginal environment have been found to associate with VVC and induce neutrophil anergy in vitro: perinuclear anti-neutrophil cytoplasmic antibodies (pANCA) and heparan sulfate. Interestingly, CAGTA antibodies have also been found with higher frequency in VVC as compared to asymptomatic colonized women. This review highlights and discusses recent advances on understanding the VVC pathogenesis mechanisms as well as the role of host defenses during the disease.

The Role of T Helper 17 (Th17) and Regulatory T Cells (Treg) in the Pathogenesis of Vulvovaginal Candidiasis among HIV-Infected Women

Background. The study sought to describe relationships between 20 cytokines and chemokines (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, G-CSF, GM-CSF, IFN-γ, MCP-1, MIP-1β, TNF-α, TGF-β1, TGF-β2, and TGF-β3) and the presence of vulvovaginal candidiasis (VVC) in women, stratified by HIV status. Methods. Plasma and genital samples were obtained from 51 clinic attendees in KwaZulu-Natal between June 2011 and December 2011. Cytokine and chemokine concentrations were measured by Luminex® multiplex immunoassays. Multiple comparisons of means of cytokine/chemokine levels displaying significant differences in univariate analyses across the study groups were performed using post hoc Bonferroni pairwise tests considering a type I error rate of 0.05. A discriminant analysis (DA) was carried out to identify linear combinations of variates that would maximally discriminate group memberships. Results. Of the 51 participants, 16/26 HIV-infected and 15/25 HIV-uninfected women were diagnosed with VVC. DA identified 2 variables (MIP-1β and TGF-β3) in plasma (Box’s M (5.49), $p$ (0.57) > α (0.001); Wilks’ lambda = 0.116, $p<0.0001$ ) and 1 variable (IL-13) in vaginal secretions (Box’s M (2.063), $p$ (0.37) > α (0.001); Wilks’ lambda = .677, $p<0.0001$ ) as able to discriminate the HIV + VVC + group, whilst TGF-β1 in plasma discriminated the HIV + VVC − group. Mean concentrations of genital IL-6, IL-8, IL-10, IL-17, and TGF-β3 were significantly higher in HIV infected women coinfected with VVC. Conclusions. In HIV-infected women, VVC might be explained by a decline of Th17 cells, hence a decrease of Th17/Treg ratio.

Candida albicans adhesion to central venous catheters: Impact of blood plasma-driven germ tube formation and pathogen-derived adhesins

Candida albicans-related bloodstream infections are often associated with infected central venous catheters (CVC) triggered by microbial adhesion and biofilm formation. We utilized single-cell force spectroscopy (SCFS) and flow chamber models to investigate the adhesion behavior of C. albicans yeast cells and germinated cells to naïve and human blood plasma (HBP)-coated CVC tubing. Germinated cells demonstrated up to 56.8-fold increased adhesion forces to CVC surfaces when compared to yeast cells. Coating of CVCs with HBP significantly increased the adhesion of 60-min germinated cells but not of yeast cells and 30-min germinated cells. Under flow conditions comparable to those in major human veins, germinated cells displayed a flow directional-orientated adhesion pattern to HBP-coated CVC material, suggesting the germ tip to serve as the major adhesive region. None of the above-reported phenotypes were observed with germinated cells of an als3Δ deletion mutant, which displayed similar adhesion forces to CVC surfaces as the isogenic yeast cells. Germinated cells of the als3Δ mutant also lacked a clear flow directional-orientated adhesion pattern on HBP-coated CVC material, indicating a central role for Als3 in the adhesion of germinated C. albicans cells to blood exposed CVC surfaces. In the common model of C. albicans, biofilm formation is thought to be mediated primarily by yeast cells, followed by surface-triggered the formation of hyphae. We suggest an extension of this model in which C. albicans germ tubes promote the initial adhesion to blood-exposed implanted medical devices via the germ tube-associated adhesion protein Als3.

Applying the Host-Microbe Damage Response Framework to Candida Pathogenesis: Current and Prospective Strategies to Reduce Damage

Disease is a complex outcome that can occur as a result of pathogen-mediated damage, host-mediated damage or both. This has led to the revolutionary concept of the damage response framework (DRF) that defines microbial virulence as a function of host immunity. The DRF outlines six scenarios (classes) of host damage or beneficial outcomes, depending on the microbe and the strength of the immune response. Candida albicans is uniquely adapted to its human host and can exist as either a commensal, colonizing various anatomical sites without causing notable damage, or as a pathogen, with the ability to cause a diverse array of diseases, ranging from mucosal to invasive systemic infections that result in varying levels of microbe-mediated and/or host-mediated damage. We recently categorized six different forms of candidiasis (oropharyngeal, hematogenous, intra-abdominal, gastrointestinal, denture stomatitis, and vulvovaginitis) into independent DRF classes, supporting a contemporary view of unique mechanisms of pathogenesis for these Candida infections. In this review, we summarize the evidence for the pathogenesis of these various forms of candidiasis in the context of the DRF with the further intent to provide insights into strategies to achieve a level of host response or outcome otherwise, that limits host damage.

Recurrent Vulvovaginal Candidiasis: The Causative Agents, Clinical Signs and Susceptibility to Fluconazole in Gonabad City, Northeast Iran

Background:

Recurrent vulvovaginal candidiasis (RVVC) is the second most common cause of genital tract infection in females. Excessive use of fluconazole and other azoles is likely to cause the emergence of the resistant species of Candida.

Objective :

The purpose of this research was to identify Candida isolates from RVVC and the antifungal effect of fluconazole against them.

Methods :

In this study, 152 patients with vulvovaginal candidiasis were evaluated for the RVVC form. The Candida isolates were purified using CHROMagar Candida and identified based on the nuclear ribosomal internal transcribed spacer (ITS1-ITS2 rDNA) sequence analysis by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The antifungal susceptibility of C. albicans isolates against fluconazole was determined according to document M27-A3.

Results:

Out of 152 patients, 20 cases (13.2%) were identified as recurrent form. The frequencies of the Candida species among the patients with RVVC were C. albicans (n = 16, 80%), C. parapsilosis (n = 3, 15%) and C. tropicalis (n = 1, 5%). The most common clinical sign was vaginal discharge (60%). The mean minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of fluconazole against Candida isolates were 32 µg/mL and 64 µg/mL, respectively.

Conclusion:

C. albicans was the dominant cause of RVVC. The Candida isolates showed relatively high resistance to fluconazole in vitro. Vaginal discharge was the most common clinical sign among patients with RVVC.

Sunlight exposure, consumption of vitamin D-rich foods and vulvovaginal candidiasis in an African population: a prevalence case-control study

BACKGROUND/OBJECTIVES

To date, only two studies have investigated the relationship between vitamin D (vitD) deficiency and candidiasis in spite of vitD's antimicrobial and immunomodulatory roles. We examined the relationship between sunlight exposure and consumption of vitD-rich foods, markers of vitD status, and vulvovaginal candidiasis (VVC) in an African population to add to the limited evidence and stimulate additional research.

SUBJECTS/METHODS

Three hundred cases (females diagnosed as suffering from VVC) and three hundred controls (females diagnosed as suffering from any condition other than VVC) were selected from three health facilities in Cape Coast, Ghana. Sunlight exposure was assessed in a structured questionnaire with a food frequency questionnaire used to ascertain the frequency of consumption of vitD-rich foods.

RESULTS

Self-reported low sunlight exposure was associated with 3.38 (95% CI:1.99, 5.74) increased odds of VVC. Low and moderate sunlight exposure estimated by outdoor visits was also associated with increased odds of VVC. In sensitivity analysis restricted to matched sunlight exposure data, low and moderate exposure was associated with 5.78 (95% CI: 2.57, 12.99) and 3.53 (95% CI: 1.85, 6.75) increased odds of VVC. Odds of VVC increased with decreasing levels of consumption of vitD-rich foods (Likelihood-ratio test trend p = 0.1382). In the joint analysis, low and moderate vitD intake was associated with much higher increased odds of VVC.

CONCLUSIONS

Our findings should be confirmed in prospective studies and clinical trials to strengthen the evidence base for preventive action and to also inform clinical decision making.

Current patient perspectives of vulvovaginal candidiasis: incidence, symptoms, management and post-treatment outcomes

BACKGROUND

Vulvovaginal candidiasis (VVC) is a common infection affecting women worldwide. Reports of patterns/risk factors/trends for episodic/recurrent VVC (RVVC) are largely outdated. The purpose of this study was to obtain current patient perspectives of several aspects of VVC/RVVC.

METHODS

Business cards containing on-line survey information were distributed to healthy volunteers and patients seeking standard, elective, or referral gynecologic care in university-affiliated Obstetrics/Gynecology clinics. The internet-based questionnaire was completed by 284 non-pregnant women (78% Caucasian, 14% African American, 8% Asian).

RESULTS

The majority of the participants (78%) indicated a history of VVC with 34% defined as having RVVC. The most common signs/symptoms experienced were itching, burning and redness with similar ranking of symptoms among VVC and RVVC patients. Among risk factors, antibiotic use ranked highest followed by intercourse, humid weather and use of feminine hygiene products. A high number of respondents noted 'no known cause' (idiopathic episodes) that was surprisingly similar among women with a history of either VVC or RVVC. VVC/RVVC episodes reported were primarily physician-diagnosed (73%) with the remainder mostly reporting self-diagnosis and treating with over-the-counter (OTC) medications. Most physician-diagnosed attacks utilized a combination of pelvic examination and laboratory tests followed by prescribed antifungals. Physician-treated cases achieved a higher level of symptom relief (84%) compared to those who self-medicated (57%). The majority of women with RVVC (71%) required continual or long-term antifungal medication as maintenance therapy to control symptoms.

CONCLUSIONS

Current patient perspectives closely reflect historically documented estimates of VVC/RVVC prevalence and trends regarding symptomatology, disease management and post-treatment outcomes.

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.

Forgotten fungi-the gut mycobiome in human health and disease

The human body is home to a complex and diverse microbial ecosystem that plays a central role in host health. This includes a diversity of fungal species that is collectively referred to as our 'mycobiome'. Although research into the mycobiome is still in its infancy, its potential role in human disease is increasingly recognised. Here we review the existing literature available on the human mycobiota with an emphasis on the gut mycobiome, including how fungi interact with the human host and other microbes. In doing so, we provide a comprehensive critique of the methodologies available to research the human mycobiota as well as highlighting the latest research findings from mycological surveys of different groups of interest including infants, obese and inflammatory bowel disease cohorts. This in turn provides new insights and directions for future studies in this burgeoning research area.

Nanoparticle-Based Mycosis Vaccine

Many diseases that were considered major affliction of mankind in the past have been successfully eradicated with introduction of appropriate vaccine strategies. In order to expedite new challenges coming up to deal with various infectious diseases, nano-particulate-based subunit vaccines seem to be the demand of ordeal. The nano-vaccines can find better scope for the diseases that were not rampant in the semi-advanced world few years back. For example in present-day circumstances that corroborate with advancement in the field of medical sciences in terms of cancer chemotherapy, organ transplantation, therapy of autoimmune diseases, etc.; along with prevalence of altogether unheard diseases such as HIV infection, people are at risk of infliction with many more pathogens. In this regard, development of an effective prophylactic strategy against many opportunistic infections primarily caused by fungal pathogens needs better understanding of host pathogen relation and role of active immunity against pathogenic fungi. In the present study, we have tried to decipher effectiveness of a nano-sized vaccine delivery system in imparting protection against fungal pathogens.

The Host Cytokine Responses and Protective Immunity in Oropharyngeal Candidiasis

Over the last three decades, the prevalence of oropharyngeal fungal infections has increased enormously, mainly due to an increasing population of immunocompromised patients, including individuals with HIV infection, transplant recipients, and patients receiving cancer therapy. The vast majority of these infections are caused by Candida species. The presence of cytokines in infected tissues ultimately dictates the host defense processes that are specific to each pathogenic organism. During oral infection with Candida, a large number of pro-inflammatory and immunoregulatory cytokines are generated in the oral mucosa. The main sources of these cytokines are oral epithelial cells, which maintain a central role in the protection against fungal organisms. These cytokines may drive the chemotaxis and effector functions of innate and/or adaptive effector cells, such as infiltrating neutrophils and T-cells in immunocompetent hosts, and CD8+ T-cells in HIV+ hosts. Epithelial cells also have direct anti- Candida activity. Several studies have provided a potential link between lower levels of certain pro-inflammatory cytokines and susceptibility to oral C. albicans infection, suggesting that such cytokines may be involved in immune protection. The exact role of these cytokines in immune protection against oropharyngeal candidiasis is still incompletely understood and requires further investigation. Identification of such cytokines with the ability to enhance anti-fungal activities of immune effector cells may have therapeutic implications in the treatment of this oral infection in the severely immunocompromised host.

Candida albicans Pathogenesis: Fitting within the Host-Microbe Damage Response Framework

Historically, the nature and extent of host damage by a microbe were considered highly dependent on virulence attributes of the microbe. However, it has become clear that disease is a complex outcome which can arise because of pathogen-mediated damage, host-mediated damage, or both, with active participation from the host microbiota. This awareness led to the formulation of the damage response framework (DRF), a revolutionary concept that defined microbial virulence as a function of host immunity. The DRF outlines six classifications of host damage outcomes based on the microbe and the strength of the immune response. In this review, we revisit this concept from the perspective of Candida albicans, a microbial pathogen uniquely adapted to its human host. This fungus commonly colonizes various anatomical sites without causing notable damage. However, depending on environmental conditions, a diverse array of diseases may occur, ranging from mucosal to invasive systemic infections resulting in microbe-mediated and/or host-mediated damage. Remarkably, C. albicans infections can fit into all six DRF classifications, depending on the anatomical site and associated host immune response. Here, we highlight some of these diverse and site-specific diseases and how they fit the DRF classifications, and we describe the animal models available to uncover pathogenic mechanisms and related host immune responses.

Microsatellite analysis of genotype distribution patterns of Candida albicans vulvovaginal candidiasis in Nanjing, China and its association with pregnancy, age and clinical presentation

PURPOSE

To characterize the genotype distribution pattern of Candida albicans associated with vulvovaginal candidiasis (VVC) in Nanjing, China by microsatellite genotyping.

METHODS

A questionnaire was completed by each patient diagnosed with VVC. A total of 208 independent C. albicans was isolated from 208 patients. Microsatellite genotyping characterized the genotype distribution by analysis of the CAI locus marker.

RESULTS

PCR of CAI fragments showed the three major genotypes contained 30:45, 21:21 and 32:46 alleles among the 51 genotypes detected, accounting for 29.3, 13.0 and 12.0 % of 208 clinical isolates. Genotype distributions had a similar pattern among different clinical presentations (P = 0.219). In both groups of the (21-30) and (31-40) years, 30:45 was the most frequent genotype allele detected. In the (21-30) year females, 16.5 % of the isolated strains had the genotype 21:21, while the same genotype in the group of (31-40) years was 6.9 %. Genotype distributions were significant difference between the pregnant and non-pregnant women (P < 0.001). 30:45 was detected only one in the 23 pregnant women.

CONCLUSIONS

The results indicated a unique genotype distribution of C. albicans associated with VVC in Nanjing, eastern China and a different distribution pattern was also detected in pregnant women compared to non-pregnant women.

Chronic vulvovaginal Candida hypersensitivity: An underrecognized and undertreated disorder by allergists

Vulvovaginal candidiasis infections are estimated to occur at least once during the lifetime of 75% of the female population. It has been proposed that some women with recurrent vulvovaginal candidiasis (RVVC) develop sensitization to Candida albicans and clinically improve in response to Candida immunotherapy. Here, we report a case series of 12 women diagnosed with chronic vulvovaginal Candida hypersensitivity subsequently treated with Candida immunotherapy and review potential systemic and localized host immune defense mechanisms involved in C. albicans overgrowth and sensitization. A retrospective review of vulvovaginal Candida hypersensitivity in women who were treated with C. albicans immunotherapy over the past eight years was conducted. Twelve women who qualified for a diagnosis of vulvovaginal Candida hypersensitivity were treated with Candida immunotherapy. Eleven of the 12 (92%) women reported clinical improvement after immunotherapy. The majority of these women were not sensitized to seasonal or perennial aeroallergens and clinically responded to lower concentrations of C. albicans allergen than what has been previously reported. In general, Candida immunotherapy was well tolerated. Chronic vulvovaginal Candida hypersensitivity is an underrecognized disorder by primary care physicians and therefore an undertreated disorder by allergists. A double-blinded, placebo-controlled randomized trial is necessary to firmly establish the efficacy of treatment with Candida immunotherapy. This investigation should be designed to include mechanistic studies that would help to better understand the etiology of this disorder.

Factors Associated with Symptomatic Vulvovaginal Candidiasis: A Study among Women Attending a Primary Healthcare Clinic in Kwazulu-Natal, South Africa

Background:

Symptomatic vulvovaginal candidiasis (VVC) is one of the most common problems leading women to seek advice in primary healthcare facilities.

Aim:

The aim of this study is to describe the associations between some hypothesized factors and the presence of symptomatic VVC.

Subjects and Methods:

An analytical cross-sectional study was conducted. A total of 90 women diagnosed with symptomatic VVC and 108 women without symptomatic VVC were recruited when attending Umlazi D clinic, a primary health clinic in KwaZulu-Natal, South Africa between June 2011 and December 2011. Confirmed symptomatic VVC was determined by Gram stain and microbiological culture of vaginal swabs. For human immunodeficiency virus (HIV)-infected women, HIV ribonucleic acid load in plasma and genital fluid was determined by real-time-polymerase chain reaction (BioMerieux, Lyon, France). CD4 counts were obtained from patients’ medical records. Data were analyzed using the statistical package for the social sciences (SPSS) version 21.0 (SPSS Inc.; Chicago, IL, USA). Multiple logistic regression models were used to exclude univariate confounders. All tests were two-sided and a P < 0.05 was considered to be significant.

Results:

A total of 90% (81/90) of patients with symptomatic VVC complained of vulval itching, soreness and vaginal discharge when compared to 75.9% (82/108) of patients without symptomatic VVC (P < 0.01). Whilst pregnancy was independently associated with symptomatic VVC (P < 0.01), the latter was inversely related to Nugent's scores (P < 0.01). When compared with HIV negative women, the odds for symptomatic VVC increased among women with HIV-associated immunocompromise (CD4 counts < 200 cells/mm³, P < 0.001), significantly shedding HIV in their genital tracts (P = 0.04), with plasma HIV load > 1000 copies/mL (P < 0.001). There was a significant negative association between the use of highly active anti-retroviral therapy and the presence of symptomatic VVC in HIV-infected women (P < 0.01).

Conclusion:

Although symptomatic VVC is not classified as acquired immunodeficiency syndrome-related condition, HIV-related immune compromised women and particularly those who are anti-retroviral therapy-naïve are likely to develop symptomatic VVC.

Genital mycotic infections with canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes mellitus: a pooled analysis of clinical studies

OBJECTIVE

To characterize genital mycotic infections with canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes mellitus (T2DM) using pooled data from Phase 3 studies.

RESEARCH DESIGN AND METHODS

Genital mycotic infections with canagliflozin 100 and 300 mg were evaluated in Population 1 (N = 2313; mean exposure [weeks]: canagliflozin, 24.3; placebo, 23.8), including patients from four placebo-controlled studies, and Population 2 (N = 9439; mean exposure [weeks]: canagliflozin, 68.1; control, 64.4), including patients from eight placebo/active-controlled studies (including older patients and those with renal impairment or high cardiovascular disease risk).

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT01081834; NCT01106625; NCT01106677; NCT01106690; NCT01032629; NCT01064414; NCT01106651; NCT00968812.

MAIN OUTCOME MEASURES

Adverse events suggestive of genital mycotic infections were recorded, with additional information collected using supplemental electronic case report forms.

RESULTS

In Population 1, genital mycotic infection incidence was higher with canagliflozin 100 and 300 mg than placebo (95% confidence intervals excluded zero) in females (10.4%, 11.4%, 3.2%) and males (4.2%, 3.7%, 0.6%). These were generally mild to moderate in intensity, none were serious, and few led to discontinuation. Most events with canagliflozin were treated with antifungal therapies, and median symptom duration following treatment initiation was similar across groups; few patients had >1 event (females, 2.3%; males, 0.9%). Findings with canagliflozin 100 and 300 mg versus control were similar in Population 2 (females: 14.7%, 13.9%, 3.1%; males: 7.3%, 9.3%, 1.6%); a low proportion of males underwent circumcision across groups. Most events with canagliflozin occurred within the first 4 months in females and first year in males; no consistent evidence of dose dependence was observed. Key limitations included lack of laboratory confirmation for most events and variable treatment methods.

CONCLUSIONS

Genital mycotic infection incidences were higher with canagliflozin than control in patients with T2DM; events were generally mild to moderate in intensity and responded to standard treatments.

Candida albicans pathogenicity mechanisms

The polymorphic fungus Candida albicans is a member of the normal human microbiome. In most individuals, C. albicans resides as a lifelong, harmless commensal. Under certain circumstances, however, C. albicans can cause infections that range from superficial infections of the skin to life-threatening systemic infections. Several factors and activities have been identified which contribute to the pathogenic potential of this fungus. Among them are molecules which mediate adhesion to and invasion into host cells, the secretion of hydrolases, the yeast-to-hypha transition, contact sensing and thigmotropism, biofilm formation, phenotypic switching and a range of fitness attributes. Our understanding of when and how these mechanisms and factors contribute to infection has significantly increased during the last years. In addition, novel virulence mechanisms have recently been discovered. In this review we present an update on our current understanding of the pathogenicity mechanisms of this important human pathogen.

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.

Candida albicans yeast and hyphae are discriminated by MAPK signaling in vaginal epithelial cells

We previously reported that a bi-phasic innate immune MAPK response, constituting activation of the mitogen-activated protein kinase (MAPK) phosphatase MKP1 and c-Fos transcription factor, discriminates between the yeast and hyphal forms of Candida albicans in oral epithelial cells (ECs). Since the vast majority of mucosal Candida infections are vaginal, we sought to determine whether a similar bi-phasic MAPK-based immune response was activated by C. albicans in vaginal ECs. Here, we demonstrate that vaginal ECs orchestrate an innate response to C. albicans via NF-κB and MAPK signaling pathways. However, unlike in oral ECs, the first MAPK response, defined by c-Jun transcription factor activation, is delayed until 2 h in vaginal ECs but is still independent of hypha formation. The 'second' or 'late' MAPK response, constituting MKP1 and c-Fos transcription factor activation, is identical to oral ECs and is dependent upon both hypha formation and fungal burdens. NF-κB activation is immediate but independent of morphology. Furthermore, the proinflammatory response in vaginal ECs is different to oral ECs, with an absence of G-CSF and CCL20 and low level IL-6 production. Therefore, differences exist in how C. albicans activates signaling mechanisms in oral and vaginal ECs; however, the activation of MAPK-based pathways that discriminate between yeast and hyphal forms is retained between these mucosal sites. We conclude that this MAPK-based signaling pathway is a common mechanism enabling different human epithelial tissues to orchestrate innate immune responses specifically against C. albicans hyphae.

The vaginal microbiome in health and disease

Infections of the vaginal tract result from perturbations in the complex interactions between the microbiome and the host vaginal ecosystem. Recent data have linked specific vaginal microbes and urogenital infection with preterm birth. Here we discuss how next-generation sequencing-based approaches to study the vaginal microbiome will be important for defining what constitutes an imbalance of the microbiome and the associated host conditions that lead to subsequent infection and disease states. These studies will provide clinicians with reliable diagnostic tools and treatments for women who are at increased risk for vaginal infections, preterm birth, HIV and other sexually acquired diseases, and will provide opportunities for intervention.

Th17 cells and IL-17 in protective immunity to vaginal candidiasis

BACKGROUND

Th17 cells play a major role in coordinating the host defence in oropharyngeal candidiasis. In this study we investigated the involvement of the Th17 response in an animal model of vulvovaginal candidiasis (VVC).

METHODS

To monitor the course of infection we exploited a new in vivo imaging technique.

RESULTS

i) The progression of VVC leads to a strong influx of neutrophils in the vagina soon after the challenge which persisted despite the resolution of infection; ii) IL-17, produced by vaginal cells, particularly CD4 T cells, was detected in the vaginal wash during the infection, reaching a maximum 14 days after the challenge; iii) The amount and kinetics of IL-23 in vaginal fluids were comparable to those in vaginal cells; iv) The inhibition of Th17 differentiation led to significant inhibition of IL-17 production with consequent exacerbation of infection; v) An increased production of βdefensin 2 was manifested in cells of infected mice. This production was strongly reduced when Th17 differentiation was inhibited and was increased by rIL-17 treatment.

CONCLUSIONS

These results imply that IL-17 and Th17, along with innate antimicrobial factors, have a role in the immune response to vaginal candidiasis.

Association between mannose-binding lectin and interleukin-1 receptor antagonist gene polymorphisms and recurrent vulvovaginal candidiasis

OBJECTIVE

The influence of functional polymorphisms in the genes coding for mannose-binding lectin (MBL) and interleukin-1 receptor antagonist (IL-1ra) on recurrent vulvovaginal candidiasis (RVVC) were examined in an urban Brazilian population.

METHODS

DNA was isolated from buccal swabs of 100 women with RVVC and 100 control women and tested by gene amplification for a single nucleotide polymorphism in codon 54 of the MBL2 gene and for a length polymorphism in intron 2 of the IL1RN gene. Genotype and allele frequencies were compared between groups.

RESULTS

The frequency of the variant MBL2 B allele, associated with reduced circulating and vaginal MBL concentrations, was 27.0% in RVVC and 8.5% in control women (p < .0001). The MBL2 B,B genotype was present in 12% of RVVC patients and 1% of controls (p = .0025). The IL1RN 2 allele frequency, associated with the highest level of unopposed IL-1β activity, was 24.0% in RVVC and 23.4% in controls. The IL1RN genotype distribution was also similar in both groups.

CONCLUSION

Carriage of the MBL2 codon 54 polymorphism, but not the IL1RN length polymorphism, predisposes to RVVC in Brazilian women.

Hyaluronan in vaginal secretions: association with recurrent vulvovaginal candidiasis

OBJECTIVE

We evaluated whether vaginal concentrations of hyaluronan were altered in women with recurrent vulvovaginal candidiasis (RVVC).

STUDY DESIGN

Lavage samples from 17 women with acute RVVC, 27 women who were receiving a maintenance antifungal regimen, and 24 control women were tested for hyaluronan and interleukin (IL)-6, IL-12, and IL-23 by enzyme-linked immunosorbent assay.

RESULTS

Median vaginal hyaluronan concentrations were 33.8 ng/mL (range, 21.6-66.3 ng/mL) in women with acute RVVC, 15.0 ng/mL (range, 11.2-50.6 ng/mL) in women who were receiving maintenance therapy, and 4.2 ng/mL (range, 3.6-12.0 ng/mL) in control subjects (P </= .02). The vaginal hyaluronan concentration was 27.4 ng/mL (range, 15.4-37.7 ng/mL) when Candida was detected by microscopy and 9.5 ng/mL (range, 7.7-14.6 ng/mL) in microscopy-negative cases (P = .0354). Elevated hyaluronan levels were associated with itching plus burning (40.7 ng/mL) or itching plus discharge (42.1 ng/mL), as opposed to itching only (6.2 ng/mL; P = .0152). Hyaluronan and IL-6 levels were correlated (P = .0009).

CONCLUSION

Hyaluronan release is a component of the host response to a candidal infection and may contribute to symptoms.

Trifluoromethanesulfonic acid-based proteomic analysis of cell wall and secreted proteins of the ascomycetous fungi Neurospora crassa and Candida albicans

Cell wall proteins from purified Candida albicans and Neurospora crassa cell walls were released using trifluoromethanesulfonic acid (TFMS) which cleaves the cell wall glucan/chitin matrix and deglycosylates the proteins. The cell wall proteins were then characterized by SDS-PAGE and identified by proteomic analysis. The analyses for C. albicans identified 15 cell wall proteins and six secreted proteins. For N. crassa, the analyses identified 26 cell wall proteins and nine secreted proteins. Most of the C. albicans cell wall proteins are found in the cell walls of both yeast and hyphae cells, but some cell type-specific cell wall proteins were observed. The analyses showed that the pattern of cell wall proteins present in N. crassa vegetative hyphae and conidia (asexual spores) are quite different. Almost all of the cell wall proteins identified in N. crassa have close homologs in the sequenced fungal genomes, suggesting that these proteins have important conserved functions within the cell wall.

Rethinking T cell immunity in oropharyngeal candidiasis

The disproportionate increase in oropharyngeal candidiasis (OPC) compared with systemic and vaginal candidiasis in female patients with AIDS has been a paradox for almost three decades. New data now show that severe OPC develops in Th17-deficient mice, but not Th1-deficient mice, implicating Th17-induced effector molecules in resistance to oral disease. These findings clarify and extend our current thinking about how CD4 T cell deficiency influences susceptibility to OPC.

Substitution of methionine 63 or 83 in S100A9 and cysteine 42 in S100A8 abrogate the antifungal activities of S100A8/A9: potential role for oxidative regulation

S100A8 and S100A9 and their heterocomplex calprotectin (S100A8/A9) are abundant cytosolic constituents in human neutrophils previously shown to possess antifungal activity. This study was designed to investigate mechanisms involved in the modulation of the antifungal properties of S100A8/A9. S100A8, S100A9 and site-directed mutants of both proteins were tested for their antifungal effect against Candida albicans in microplate dilution assays. Whereas S100A8 alone did not inhibit fungal growth, S100A9 by itself had a moderate antifungal effect. Combining both proteins had the strongest effect. Supporting a potential role for oxidation in S100A8/A9, substitution of methionine 63 or 83 of S100A9 resulted in the loss of antifungal activity. Additionally, the substitution to alanine of cysteine 42 of S100A8 also caused a loss of S100A8's ability to enhance S100A9's antifungal effect. Overall, our data indicate that both S100A8 and S100A9 are required for their fully active antifungal effect and that oxidation regulates S100A8/A9 antifungal activity through mechanisms that remain to be elucidated and evaluated. Finally, together with our previous work describing the oxidation-sensitive anti-inflammatory effects of S100A8/A9, we propose that S100A8/A9 exerts an anti-inflammatory activity in healthy state and that conditions associated with oxidative stress activate the antifungal activity of S100A8/A9.

Glycerol monolaurate does not alter rhesus macaque (Macaca mulatta) vaginal lactobacilli and is safe for chronic use

Glycerol monolaurate (GML) is a fatty acid monoester that inhibits growth and exotoxin production of vaginal pathogens and cytokine production by vaginal epithelial cells. Because of these activities, and because of the importance of cytokine-mediated immune activation in human immunodeficiency virus type 1 (HIV-1) transmission to women, our laboratories are performing studies on the potential efficacy of GML as a topical microbicide to interfere with HIV-1 transmission in the simian immunodeficiency virus-rhesus macaque model. While GML is generally recognized as safe by the FDA for topical use, its safety for chronic use and effects on normal vaginal microflora in this animal model have not been evaluated. GML was therefore tested both in vitro for its effects on vaginal flora lactobacilli and in vivo as a 5% gel administered vaginally to monkeys. In vitro studies demonstrated that lactobacilli are not killed by GML; GML blocks the loss of their viability in stationary phase and does not interfere with lactic acid production. GML (5% gel) does not quantitatively alter monkey aerobic vaginal microflora compared to vehicle control gel. Lactobacilli and coagulase-negative staphylococci are the dominant vaginal aerobic microflora, with beta-hemolytic streptococci, Staphylococcus aureus, and yeasts sporadically present; gram-negative rods are not part of their vaginal flora. Colposcopy and biopsy studies indicate that GML does not alter normal mucosal integrity and does not induce inflammation; instead, GML reduces epithelial cell production of interleukin 8. The studies suggest that GML is safe for chronic use in monkeys when applied vaginally; it does not alter either mucosal microflora or integrity.

Synthetic glycopeptide vaccines combining beta-mannan and peptide epitopes induce protection against candidiasis

The first fully synthetic glycopeptide vaccines against a fungal disease have been used to combat disseminated candidiasis in mice. Six T cell peptides found in Candida albicans cell wall proteins were selected by algorithm peptide epitope searches; each was synthesized and conjugated to the fungal cell wall beta-mannan trisaccharide [beta-(Man)(3)] by novel saccharide-peptide linker chemistry to create glycopeptide conjugates. The six proteins were selected because of expression during human candidiasis and cell wall association and included: fructose-bisphosphate aldolase (Fba); methyltetrahydropteroyltriglutamate (Met6); hyphal wall protein-1 (Hwp1); enolase (Enol); glyceraldehyde-3-phosphate dehydrogenase (Gap1); and phosphoglycerate kinase (Pgk1). By immunization protocols favoring production of protective antibody, the beta-(Man)(3)-Fba, beta-(Man)(3)-Met6 and beta-(Man)(3)-Hwp1 induced protection evidenced by survival and reduced kidney fungal burden, the beta-(Man)(3)-Eno1 and beta-(Man)(3)-Gap1 gave moderate protection, and the beta-(Man)(3)-Pgk1 slightly enhanced disease. For the beta-(Man)(3)-Fba conjugate, protection was uniquely acquired through immunity against the carbohydrate and the Fba peptide. This approach based on fully synthetic chemically defined immunogens should be generally useful in vaccine development.

C. albicans colonization of human mucosal surfaces

BACKGROUND

Candida albicans is a low level commensal organism in normal human populations with the continuous potential to expand and cause a spectrum of clinical conditions.

METHODOLOGY/PRINCIPAL FINDINGS

Using ex vivo human organ cultures and populations of primary human cells, we have developed several related experimental systems to examine early-stage interactions between C. albicans and mucosal surfaces. Experiments have been conducted both with exogenously added C. albicans and with overtly normal human mucosal surfaces supporting pre-existing infections with natural isolates of Candida. Under different culture conditions, we have demonstrated the formation of C. albicans colonies on human target cells and filament formation, equivalent to tissue invasion.

CONCLUSIONS/SIGNIFICANCE

These organ culture systems provide a valuable new resource to examine the molecular and cellular basis for Candida colonization of human mucosal surfaces.

Mannose-binding lectin gene polymorphism, vulvovaginal candidiasis, and bacterial vaginosis

OBJECTIVE

To evaluate associations between polymorphisms in the gene coding for mannose-binding lectin (MBL) and the diagnosis of acute or recurrent vulvovaginal candidiasis and bacterial vaginosis

METHODS

Women at two outpatient clinics in Brazil filled out a questionnaire and were examined for the presence of vulvovaginal candidiasis or bacterial vaginosis. A buccal swab was blindly tested for codons 54 and 57 MBL2 gene polymorphisms by polymerase chain reaction and endonuclease digestion.

RESULTS

A total of 177 women were enrolled. Vulvovaginal candidiasis was identified in 78 (44.1%) women, 33 (18.6%) had bacterial vaginosis, and 66 (37.3%) were normal controls. Recurrent vulvovaginal candidiasis was present in 50 (64.1%) of the women with vulvovaginal candidiasis; 20 (60.6%) of the bacterial vaginosis patients had recurrent disease. Vulvovaginal candidiasis was associated with white race (P=.007), bacterial vaginosis was associated with nonwhite race (P=.05), and both were associated with a history of allergy (P< or =.02) and having sexual intercourse at least three times a week (P<.001). Carriage of the variant MBL2 codon 54 allele B was more frequent in women with recurrent vulvovaginal candidiasis (25.0%) than in the women with acute vulvovaginal candidiasis (17.9%) or controls (10.6%) (P=.004). Allele B was also more prevalent in women with recurrent bacterial vaginosis (22.5%) than in those with acute bacterial vaginosis (0%) (P=.009). The MBL2 codon 57 polymorphism was infrequent and not associated with vulvovaginal candidiasis or bacterial vaginosis.

CONCLUSION

The incidence of vulvovaginal candidiasis and bacterial vaginosis differs by ethnicity in Brazilian women. The MBL2 codon 54 gene polymorphism is associated with both recurrent vulvovaginal candidiasis and recurrent bacterial vaginosis.

Vulvovaginal candidosis

Despite therapeutic advances, vulvovaginal candidosis remains a common problem worldwide, affecting all strata of society. Understanding of anti-candida host defence mechanisms in the vagina has developed slowly and, despite a growing list of recognised risk factors, a fundamental grasp of pathogenic mechanisms continues to elude us. The absence of rapid, simple, and inexpensive diagnostic tests continues to result in both overdiagnosis and underdiagnosis of vulvovaginal candidosis. I review the epidemiology and pathogenesis of this infection, and also discuss management strategies.

History and update on host defense against vaginal candidiasis

Vulvovaginal candidiasis (VVC), caused by Candida albicans, remains a significant problem in women of childbearing age. While cell-mediated immunity is considered the predominant host defense mechanism against mucosal candidal infections, two decades of research from animal models and clinical studies have revealed a lack of a protective role for adaptive immunity against VVC caused by putative immunoregulatory mechanisms. Moreover, natural protective mechanisms and factors associated with susceptibility to infection have remained elusive. That is until recently, when through a live challenge model in humans, it was revealed that protection against vaginitis coincides with a non-inflammatory innate presence, whereas symptomatic infection correlates with a neutrophil infiltrate in the vaginal lumen and elevated fungal burden. Thus, instead of VVC being caused by a putative deficient adaptive immune response, it is now being considered that symptomatic vaginitis is caused by an aggressive innate response.

Clinical aspects and luteal phase assessment in patients with recurrent vulvovaginal candidiasis

OBJECTIVE

This study was undertaken to characterize the patients with recurrent vulvovaginal candidiasis.

STUDY DESIGN

Basic data of personal history and history of recurrent vulvovaginal candidiasis, lower genital tract symptoms and signs in 50 patients were analyzed in this longitudinal follow-up study including the determination of midluteal serum progesterone and urinary pregnanediol levels during the luteal phase in 84 cycles (recurrent vulvovaginal candidiasis) and 60 cycles (healthy controls).

RESULTS

All patients suffered primary idiopathic form of recurrent vulvovaginal candidiasis. Frequently, there was a striking discrepancy between severe symptoms and clinical finding, which was often negligible or normal. There was no redness and no or minimum discharge in 52% of culture documented attacks. In contrast to the healthy controls, the patients had significantly lower levels of progesterone (p<0.01) as well as those of urinary pregnanediol (p<0.05).

CONCLUSION

Culture positive attacks in patients with recurrent vulvovaginal candidiasis represented rather a form of vulvovaginal discomfort than attacks of vulvovaginal candidiasis with typical inflammatory changes. Significantly lower progesterone levels in the RVVC patients as compared to the healthy controls suggest a link between an altered hormonal status and one of possible causes of RVVC in these women.

Symptomatic candidiasis: Using self sampled vaginal smears to establish the presence ofCandida, lactobacilli, andGardnerella vaginalis

In a prospective cohort study, 10 symptomatic women with recurrent vulvovaginal candidiasis were taught how to prepare vaginal smears of their own vaginal fluids on days 7, 14, 21, and 28. The 40 smears were stained with the PAS-method and examined by three different cytopathologists for presence of Candida. Thereafter, the smears were restained with Giemsa-stain to determine presence of lactobacilli, Gardnerella vaginalis ("clue cells") and neutrophils. All three cytopathologists unequivocally established Candida blastospores and (pseudo)hyphae in 27 out of the 40 PAS-stained vaginal smears, whereas in the remaining 13 smears Candida was not found. All 10 patients had Candida in their smears during the second half of their menstrual cycle.Self sampled smears prove to be reliable for establishing the presence of Candida in symptomatic patients with candidiasis. Candida is associated with a lactobacillus-predominated vaginal flora, but with the absence of Gardnerella vaginalis. Further studies may be directed towards the interaction between the various members of the vaginal flora. This study should open molecular methodology for determining the possible interactions of lactobacilli and Candida.

Truncation of amidated fragment 33-61 of bovine α-hemoglobin: Effects on the structure and anticandidal activity

Peptides derived from endogenous hemoglobin play important biological roles in a variety of living systems. In previous works we showed that the fragment 33-61 of bovine alpha-hemoglobin (Hb33-61) and its C-terminus amidated analogue (Hb33-61a) exhibit antimicrobial activity and we determined the 3D structure of Hb33-61a bound to sodium dodecyl sulfate micelles. Here we report that Hb33-61a is lethal to Candida albicans at 6.25 microM probably through disruption of its plasma membrane. In addition, we show that, even when used at 50 microM, Hb33- 61a produces low hemolysis (16% +/- 3.0%). Recognizing that one of the key steps to study new compounds with potential pharmaceutical application is to identify the structural elements essential to express biological activity, we also investigated the anticandidal activity of Hb33- 61a fragments. The results indicated that Hb40-61a exhibits the same minimal inhibitory concentration as Hb33-61a, whereas Hb33-52a and Hb48-61a are significantly less active. Noteworthy, for all the peptides tested, we observed that C-terminus amidation produces a potentiation of their anticandidal activity and we associate that increased biological activity to a preferred structural and spatial organization of the C-terminal region favored by amidation. Finally, the data show that the most active peptides (Hb33-61a and Hb40-61a) are characterized by a central hinge joining the C-terminal region that presents, containing a beta-turn, followed by and a helical element, to the N-terminal region that presents only a beta-turn. We hypothesize that these two structured regions, by fluctuating independently in the lipid environment, may act in a coordinated fashion disrupting the yeast plasma membrane.

Management of recurrent vulvovaginal candidiasis: Unresolved issues

The introduction and widespread use of long-term maintenance suppressive fluconazole prophylaxis for recurrent vulvovaginal candidiasis (RVVC) has improved the quality of life for thousands of women worldwide. Moreover, the regimen is no longer expensive, and it is safe and well tolerated. However, the regimen frequently fails to cure the condition and serves only as an effective control measure in many cases. Moreover, some women are unable to tolerate the regimen, and new curative approaches are needed. This review presents the limitations of this suppressive regimen and a discussion of the possible reasons for these limitations and failure to cure. Also, the rationale for new drug development is reviewed here.

Phenotypic and functional characterization of vaginal dendritic cells in a rat model of Candida albicans vaginitis

This study analyzes the phenotype of vaginal dendritic cells (VDCs), their antigenic presentation and activation of T-cell cytokine secretion, and their protective role in a rat model of Candida vaginitis. Histological observation demonstrated a significant accumulation of OX62(+) VDCs in the mucosal epithelium of Candida albicans-infected rats at the third round of infection. We identified two subsets of OX62(+) VDCs differing in the expression of CD4 molecule in both noninfected and Candida-infected rats. The OX62(+) CD4(+) subset of VDCs displayed a lymphoid cell-like morphology and expressed the T-cell antigen CD5, whereas the OX62(+) CD4(-) VDC subset exhibited a myeloid morphology and was CD5 negative. Candida infection resulted in VDC maturation with enhanced expression of CD80 and CD134L on both CD4(+) and CD4(-) VDC subsets at 2 and 6 weeks after Candida infection. CD5(-) CD4(-) CD86(-) CD80(-) CD134L(+) VDCs from infected, but not noninfected, rats spontaneously released large amounts of interleukin-12 (IL-12) and tumor necrosis factor alpha, whereas all VDC subsets released comparable levels of IL-10 and IL-2 cytokines. Furthermore, OX62(+) VDCs from infected rats primed naïve CD4(+) T-cell proliferation and release of cytokines, including gamma interferon, IL-2, IL-6, and IL-10, in response to staphylococcal enterotoxin B stimulation in vitro. Adoptive transfer of highly purified OX62(+) VDCs from infected rats induced a significant acceleration of fungal clearance compared with that in rats receiving naive VDCs, suggesting a protective role of VDCs in the anti-Candida mucosal immunity. Finally, VDC-mediated protection was associated with their ability to rapidly migrate to the vaginal mucosa and lymph nodes, as assessed by adoptive transfer of OX62(+) VDCs labeled with 5 (and 6-)-carboxyfluorescein diacetate succinimidyl ester.

Role for dendritic cells in immunoregulation during experimental vaginal candidiasis

Vulvovaginal candidiasis (VVC) caused by the commensal organism Candida albicans remains a significant problem among women of childbearing age, with protection against and susceptibility to infection still poorly understood. While cell-mediated immunity by CD4+ Th1-type cells is protective against most forms of mucosal candidiasis, no protective role for adaptive immunity has been identified against VVC. This is postulated to be due to immunoregulation that prohibits a more profound Candida-specific CD4+ T-cell response against infection. The purpose of this study was to examine the role of dendritic cells (DCs) in the induction phase of the immune response as a means to understand the initiation of the immunoregulatory events. Immunostaining of DCs in sectioned murine lymph nodes draining the vagina revealed a profound cellular reorganization with DCs becoming concentrated in the T-cell zone throughout the course of experimental vaginal Candida infection consistent with cell-mediated immune responsiveness. However, analysis of draining lymph node DC subsets revealed a predominance of immunoregulation-associated CD11c+ B220+ plasmacytoid DCs (pDCs) under both uninfected and infected conditions. Staining of vaginal DCs showed the presence of both DEC-205+ and pDCs, with extension of dendrites into the vaginal lumen of infected mice in close contact with Candida. Flow cytometric analysis of draining lymph node DC costimulatory molecules and activation markers from infected mice indicated a lack of upregulation of major histocompatibility complex class II, CD80, CD86, and CD40 during infection, consistent with a tolerizing condition. Together, the results suggest that DCs are involved in the immunoregulatory events manifested during a vaginal Candida infection and potentially through the action of pDCs.

Vaginal epithelial cell anti-Candida albicans activity is associated with protection against symptomatic vaginal candidiasis

Vaginal epithelial cell (VEC) anti-Candida albicans activity, despite being measured in vitro, is considered an innate host defense mechanism. This was supported further by the fact that women protected from symptomatic infection following a live intravaginal Candida challenge had increased VEC anti-Candida activity compared to those who acquired a symptomatic infection.