Understanding Basic Mechanisms and Optimizing Assays to Evaluate the Efficacy of Vaginal Microbicides

Performance of Softcup® menstrual cup and vulvovaginal swab samples for detection and quantification of genital cytokines

Cytokines are important mediators of immunity in the female genital tract, and their levels may be associated with various reproductive health outcomes. However, the measurement of cytokines and chemokines in vaginal fluid samples may be influenced by a variety of factors, each with the potential to affect the sensitivity and accuracy of the assay, including the interpretation and comparison of data. We measured and compared cytokine milieu in samples collected via Softcup® menstrual cup versus vulvovaginal swabs. One hundred and eighty vulvovaginal swabs from CAPRISA 088 and 42 Softcup supernatants from CAPRISA 016 cohorts of pregnant women were used to measure the concentrations of 28 cytokines through multiplexing. Cytokines measured in this study were detectable in each of the methods however, SoftCup supernatants showed consistently, higher detectability, expression ratios, and mean concentration of cytokines than vulvovaginal swabs. While mean concentrations differed, the majority of cytokines correlated between SoftCup supernatants and vulvovaginal swabs. Additionally, there were no significant differences in a number of participants between the two sampling methods for the classification of genital inflammation. Our findings suggest that SoftCup supernatants and vulvovaginal swab samples are suitable for the collection of genital specimens to study biological markers of genital inflammatory response. However, the Softcup menstrual cup performs better for the detection and quantification of soluble biomarkers that are found in low concentrations in cervicovaginal fluid.

Evaluation of the novel vaginal contraceptive agent PPCM in preclinical studies using sperm hyaluronan binding and acrosome status assays

Background

Polyphenylene carboxymethylene (PPCM) sodium salt is a promising multipurpose technology for prevention of both sexually transmitted infections (STIs) and pregnancy. In preclinical studies, PPCM has demonstrated significant (1) antimicrobial activity against several important viral and bacterial pathogens and (2) contraceptive activity associated with premature acrosome loss.

Objective

To further evaluate a vaginal antimicrobial compound as a contraceptive agent in preclinical studies utilizing a repurposed hyaluronan binding assay (HBA).

Materials and methods

Semen samples containing either neat semen or washed spermatozoa were treated with increasing concentrations of PPCM or calcium ionophore A23187 (positive control). Sperm inactivation was measured by two methods: (1) double acrosome staining (AS), and (2) a hyaluronan binding assay (HBA^®). Percentage of inactivated sperm was compared between untreated control sperm and those treated with PPCM or A23187.

Results

PPCM had a significant (p < 0.05) and dose‐dependent effect on sperm inactivation in both assays, with HBA detecting a higher proportion of inactivated sperm than AS. PPCM did not affect sperm motility and exhibited equivalent responses in the neat and washed samples.

Discussion

Both HBA and AS confirmed that spermatozoa were rapidly inactivated at PPCM concentrations likely present in the vagina under actual use conditions and in a time‐frame comparable to in vivo migration of spermatozoa out of seminal plasma into cervical mucus.

Conclusion

PPCM vaginal gel may provide contraceptive protection as well as help with STI prevention. HBA may be a sensitive and much needed biomarker for sperm activity in future contraceptive development.

Development of multipurpose technologies products for pregnancy and STI prevention: update on polyphenylene carboxymethylene MPT gel development†

Current modern contraceptives rely heavily on the use of hormones. These birth control drug products, including pills, patches, injections, and IUDS, have been extremely beneficial to millions of women and their families over the past 50 years. But a surprisingly high number of women abandon such modern methods, many because they cannot tolerate the side effects and others because they have medical issues for which hormonal methods are contraindicated. In addition, modern hormonal methods are simply not available to many women. The extent of this problem is steadily becoming more apparent. We present the case for developing simple nonhormonal vaginal products that women can use when needed, ideal products that are multipurpose and offer both contraception and sexually transmitted disease protection. Gel-based vaginal products are particularly well suited for this purpose. Gels are easy to use, highly acceptable to many women, and can be safely formulated to enhance natural vaginal defenses against infection. However, the development of a new chemical entity for this application faces significant technical and regulatory hurdles. These challenges and our solutions are described for polyphenylene carboxymethylene (PPCM), a novel topical drug in a vaginal gel nearing human clinical trials. We have advanced PPCM from benchtop to IND-enabling studies and provide a brief description of the complex development process. We also describe a simple lab assay which can be used as a biomarker for contraceptive activity to enable pharmacodynamic studies in vaginal contraceptive development, both preclinically and in early human clinical trials.

Randomized Cross-Sectional Study to Compare HIV-1 Specific Antibody and Cytokine Concentrations in Female Genital Secretions Obtained by Menstrual Cup and Cervicovaginal Lavage

Introduction

Optimizing methods for genital specimen collection to accurately characterize mucosal immune responses is a priority for the HIV prevention field. The menstrual cup (MC) has been proposed as an alternative to other methods including cervicovaginal lavage (CVL), but no study has yet formally compared these two methods.

Methods

Forty HIV-infected, antiretroviral therapy-naïve women from the CAPRISA 002 acute HIV infection cohort study were randomized to have genital fluid collected using the MC with subsequent CVL, or by CVL alone. Qualitative data, which assessed levels of comfort and acceptability of MC using a 5-point Likert scale, was collected. Luminex multiplex assays were used to measure HIV-specific IgG against multiple gene products and 48 cytokines.

Results

The majority (94%) of participants indicated that insertion, wearing and removal of the MC was comfortable. Nineteen MCs with 18 matching, subsequent CVLs and 20 randomized CVLs were available for analysis. Mucosal IgG responses against four HIV-antigens were detected in 99% of MCs compared to only 80% of randomized CVLs (p = 0.029). Higher specific antibody activity and total antibodies were observed in MCs compared to CVL (all p<0.001). In MCs, 42/48 (88%) cytokines were in the detectable range in all participants compared to 27/48 (54%) in CVL (p<0.001). Concentrations of 22/41 cytokines (53.7%) were significantly higher in fluid collected by MC. Both total IgG (r = 0.63; p = 0.005) and cytokine concentrations (r = 0.90; p<0.001) correlated strongly between MC and corresponding post-MC CVL.

Conclusions

MC sampling improves the detection of mucosal cytokines and antibodies, particularly those present at low concentrations. MC may therefore represent an ideal tool to assess immunological parameters in genital secretions, without interfering with concurrent collection of conventional CVL samples.

Comparison of the vaginal microbial communities in women with recurrent genital HSV receiving acyclovir intravaginal rings

Vaginally administered antiviral agents may reduce the risk of HIV and HSV acquisition. Delivery of these drugs using intravaginal rings (IVRs) holds the potential benefits of improving adherence and decreasing systemic exposure, while maintaining steady-state drug levels in the vaginal tract. Elucidating how IVRs interact with the vaginal microbiome constitutes a critical step in evaluating the safety of these devices, as shifts the vaginal microbiome have been linked with several disease states. To date, clinical IVR trials have relied on culture-dependent methods that omit the high diversity of unculturable microbial population. Longitudinal, culture-independent characterization of the microbiota in vaginal samples from 6 women with recurrent genital HSV who used an acyclovir IVR was carried out and compared to the communities developing in biofilms on the IVR surface. The analysis utilized Illumina MiSeq sequence datasets generated from bar-coded amplicons of 16S rRNA gene fragments. Specific taxa in the vaginal communities of the study participants were found to be associated with the duration of recurrent genital HSV status and the number of HSV outbreaks. Taxonomic comparison of the vaginal and IVR biofilm communities did not reveal any significant differences, suggesting that the IVRs were not systematically enriched with members of the vaginal microbiome. Device usage did not alter the participants' vaginal microbial communities, within the confines of the current study design. Rigorous, molecular analysis of the effects of intravaginal devices on the corresponding microbial communities shows promise for integration with traditional approaches in the clinical evaluation of candidate products.

Unbiased proteomics analysis demonstrates significant variability in mucosal immune factor expression depending on the site and method of collection

Female genital tract secretions are commonly sampled by lavage of the ectocervix and vaginal vault or via a sponge inserted into the endocervix for evaluating inflammation status and immune factors critical for HIV microbicide and vaccine studies. This study uses a proteomics approach to comprehensively compare the efficacy of these methods, which sample from different compartments of the female genital tract, for the collection of immune factors. Matching sponge and lavage samples were collected from 10 healthy women and were analyzed by tandem mass spectrometry. Data was analyzed by a combination of differential protein expression analysis, hierarchical clustering and pathway analysis. Of the 385 proteins identified, endocervical sponge samples collected nearly twice as many unique proteins as cervicovaginal lavage (111 vs. 61) with 55% of proteins common to both (213). Each method/site identified 73 unique proteins that have roles in host immunity according to their gene ontology. Sponge samples enriched for specific inflammation pathways including acute phase response proteins (p = 3.37×10⁻²⁴) and LXR/RXR immune activation pathways (p = 8.82×10⁻²²) while the role IL-17A in psoriasis pathway (p = 5.98×10⁻⁴) and the complement system pathway (p = 3.91×10⁻³) were enriched in lavage samples. Many host defense factors were differentially enriched (p<0.05) between sites including known/potential antimicrobial factors (n = 21), S100 proteins (n = 9), and immune regulatory factors such as serpins (n = 7). Immunoglobulins (n = 6) were collected at comparable levels in abundance in each site although 25% of those identified were unique to sponge samples. This study demonstrates significant differences in types and quantities of immune factors and inflammation pathways collected by each sampling technique. Therefore, clinical studies that measure mucosal immune activation or factors assessing HIV transmission should utilize both collection methods to obtain the greatest representation of immune factors secreted into the female genital tract.

Combinations of 3-hydroxyphthalic anhydride-modified ovalbumin with antiretroviral drug-based microbicide candidates display synergistic and complementary effects against HIV-1 infection

BACKGROUND

The development of a safe, effective, and affordable microbicide to prevent the sexual transmission of HIV combination is urgently needed. Our previous studies demonstrated that 3-hydroxyphthalic anhydride-modified chicken ovalbumin (HP-OVA) exhibited potent antiviral activity against a broad spectrum of HIV, simian immunodeficiency virus, and herpes simplex virus, making it a promising candidate as a component of combination microbicide. We intended to evaluate potential the synergistic anti-HIV-1 effect of HP-OVA in combination with antiretroviral drug (ARV)-based microbicide candidates.

METHODS

The antiviral activity of HP-OVA and the ARVs, including HIV-1 entry inhibitors (T20, C52L, NB64, NBD556, AMD3100, and Maraviroc) and reverse transcriptase inhibitors (Tenofovir, UC781, and TMC120), tested alone or in combination, against HIV-1 X4 and R5 viruses, including some drug-resistant strains, was determined in MT-2 and peripheral blood mononuclear cells using p24 assay. The immune responses induced by HP-OVA that was applied in the vaginas of rats were detected by enzyme-linked immunosorbent assay.

RESULTS

When each of these ARV-based microbicide candidates was combined with HP-OVA, synergistic activity was observed against infection by both X4 and R5 strains, and the degree of synergy differed in each case. HP-OVA was highly effective against several ARV-resistant HIV-1 strains, suggesting that combining HP-OVA with these ARV-based microbicide candidates might work cooperatively against both drug-sensitive and -resistant HIV-1 strains. Human body fluids and human proteins had little or no effects on HP-OVA-mediated inhibitory activity against HIV-1 infection. HP-OVA formulated in the universal gel maintained its antiviral activity for at least 1 month and only induced weak immune responses after its multiple applications in the vaginas of rats.

CONCLUSIONS

Synergistic and complementary effects against infection by a broad spectrum of HIV-1 strains were observed by combining HP-OVA with the ARV-based microbicide candidates. These findings provide a sound scientific platform for the development of a safe, effective, and affordable combination microbicide to prevent the sexual transmission of HIV and other sexually transmissible viruses.

Should microbicides be controlled by women or by physicians?

In 2007, nearly 7000 new cases of HIV infection occurred each day. There is a constant increase in the proportion of women newly infected with HIV in the global population; this increase is particularly high in some areas of the world such as sub-Saharan Africa. Microbicides are products that are being developed to empower women against HIV. First- and second-generation microbicides are broad-spectrum products that include surface active agents, vaginal defense enhancers, and blocking agents. Third-generation microbicides are HIV-specific and include replication and entry inhibitors formulated as gels or as vaginal rings. However, there is a concern that antiretroviral-based microbicides could lead to drug resistance if they are used by HIV-positive women who are unaware of their HIV status. To reach the highest number of women possible, microbicides should be available over-the-counter, which might not be the case with antiretroviral-based formulations. In contrast, non-antiretroviral-based microbicides will have the advantage of being initiated and controlled by women themselves and they will not jeopardize the use of life-saving drugs.

Microbicides in the prevention of HIV infection: current status and future directions

More than 28 years since the first cases of HIV/AIDS, there is still no cure or vaccine. The worst affected region is sub-Saharan Africa and, increasingly, it is young women who are bearing the brunt of the epidemic. Consequently, there is an urgent need for HIV prevention options for women in developing countries. Microbicides are topical products that can be used vaginally by women to impede sexual transmission of HIV and thus represent one of the most promising prevention strategies. Efficacy trials with early nonspecific microbicide gels have so far been unsuccessful, but the field has now switched its focus to products containing highly potent and highly specific antiretroviral drugs that are easier to use, and can be formulated in a variety of dosage forms to suit individual and regional preferences. However, these products have their own challenges, with a greater likelihood of absorption, and the potential for systemic toxicities or the development of resistance in infected individuals who are unaware of their HIV status. The conduct of clinical trials is complex for all microbicides, with limited availability of trial sites, difficulties in dose selection and safety monitoring, and a lack of a truly objective measure of adherence. Once a microbicide has been shown to be safe and effective, there will need to be a clear pathway to regulatory approval, and the successful launch of a product will depend on having in place appropriate methods for distribution to the women who need it, along with a strategy for ensuring that they use it correctly. This will require substantial effort in terms of education and community engagement, and these activities need to be initiated well in advance of microbicide rollout.

Adherence and its measurement in phase 2/3 microbicide trials

Adherence optimization and measurement have emerged as critically challenging issues for clinical trials of topical microbicides. Although microbicide trials have routinely collected adherence data, their utilization in trial design, implementation, and interpretation has been inconsistent. Drawing on data-driven presentations from several focused meetings, this paper synthesizes lessons from past microbicide trials and provides recommendations for future trials of microbicide and other HIV prevention technologies. First, it describes four purposes for adherence data collection, with particular attention to intention-to-treat versus adherence-adjusted analyses for determining effectiveness. Second, the microbicide field’s experiences with adherence measures and data collection modes are discussed, including the strengths and weaknesses of various options and approaches for improving measurement. Then, several approaches to optimizing trial participants’ adherence are presented. The paper concludes with a set of recommendations for immediate use or further research.

HIV-1 neutralization profile and plant-based recombinant expression of actinohivin, an Env glycan-specific lectin devoid of T-cell mitogenic activity

The development of a topical microbicide blocking the sexual transmission of HIV-1 is urgently needed to control the global HIV/AIDS pandemic. The actinomycete-derived lectin actinohivin (AH) is highly specific to a cluster of high-mannose-type glycans uniquely found on the viral envelope (Env). Here, we evaluated AH's candidacy toward a microbicide in terms of in vitro anti-HIV-1 activity, potential side effects, and recombinant producibility. Two validated assay systems based on human peripheral blood mononuclear cell (hPBMC) infection with primary isolates and TZM-bl cell infection with Env-pseudotyped viruses were employed to characterize AH's anti-HIV-1 activity. In hPMBCs, AH exhibited nanomolar neutralizing activity against primary viruses with diverse cellular tropisms, but did not cause mitogenicity or cytotoxicity that are often associated with other anti-HIV lectins. In the TZM-bl-based assay, AH showed broad anti-HIV-1 activity against clinically-relevant, mucosally transmitting strains of clades B and C. By contrast, clade A viruses showed strong resistance to AH. Correlation analysis suggested that HIV-1's AH susceptibility is significantly linked to the N-glycans at the Env C2 and V4 regions. For recombinant (r)AH expression, we evaluated a tobacco mosaic virus-based system in Nicotiana benthamiana plants as a means to facilitate molecular engineering and cost-effective mass production. Biochemical analysis and an Env-mediated syncytium formation assay demonstrated high-level expression of functional rAH within six days. Taken together, our study revealed AH's cross-clade anti-HIV-1 activity, apparent lack of side effects common to lectins, and robust producibility using plant biotechnology. These findings justify further efforts to develop rAH toward a candidate HIV-1 microbicide.

3-hydroxyphthalic anhydride-modified chicken ovalbumin exhibits potent and broad anti-HIV-1 activity: a potential microbicide for preventing sexual transmission of HIV-1

Heterosexual transmission is the primary route by which women acquire human immunodeficiency virus (HIV)/AIDS. Thus, development of woman-controlled topical microbicides for prevention of sexual transmission of HIV is urgently needed. Here we report that 3-hydroxyphthalic anhydride-modified chicken ovalbumin (HP-OVA) exhibits potent antiviral activity against a broad spectrum of human immunodeficiency virus type 1 (HIV-1) isolates with different genotypes and biotypes. Its antiviral activity is correlated with the percentages of the chemically modified and unmodified lysines and arginines in OVA. HP-OVA inhibits HIV-1 fusion and entry through multiple mechanisms of action, including (i) blocking gp120 binding to CD4 and (ii) interfering with gp41 six-helix bundle formation. Because of the widespread availability and established safety profile of OVA, HP-OVA has good potential to be developed as an effective, safe, and affordable microbicide for prevention of HIV sexual transmission.