Insertive condom-protected and condomless vaginal sex both have a profound impact on the penile immune correlates of HIV susceptibility

The penis is the primary site of HIV acquisition in heterosexual men. Elevated penile inflammatory cytokines increase sexual acquisition risk, and topically applied cytokines enhance foreskin HIV susceptibility in an explant model. However, the impact of penile-vaginal sex on these immune parameters is undefined. Heterosexual couples were recruited to the Sex, Couples and Science (SECS) Study, with the collection of penile swabs, semen, cervico-vaginal secretions, and blood after a period of abstinence, and repeated sampling up to 72 hours after either condomless (n = 30) or condom-protected (n = 8) penile-vaginal sex. Soluble immune parameters were quantified by multiplex immunoassay. Co-primary immune endpoints were penile levels of IL-8 and MIG, cytokines previously linked to penile HIV acquisition. One hour after sex there were dramatic increases in penile IL-8 and MIG levels, regardless of condom use, with a gradual return to baseline by 72 hours; similar patterns were observed for other chemoattractant chemokines. Penile cytokine changes were similar in circumcised and uncircumcised men, and repeated measures ANOVA and ANCOVA models demonstrated that the degree of change after condomless sex was explained by cytokine levels in their partners’ cervico-vaginal secretions. This may have important implications for the biology of penile HIV acquisition.

Insertive vaginal sex has a profound impact on the penile immune correlates of HIV susceptibility

ABSTRACTThe penis is the primary site of HIV acquisition in heterosexual men. Elevated penile inflammatory cytokines increase sexual acquisition risk, and topically applied cytokines enhance foreskin HIV susceptibility in an explant model. However, the impact of penile-vaginal sex on these immune parameters is undefined. Heterosexual couples were recruited to the Sex, Couples and Science (SECS) Study, with the collection of penile swabs, semen, cervico-vaginal secretions, and blood after a period of abstinence, and repeated sampling up to 72 hours after either condomless (n=30) or condom-protected (n=8) penile-vaginal sex. Soluble immune parameters were quantified by multiplex immunoassay. Co-primary immune endpoints were penile levels of IL-8 and MIG, cytokines previously linked to penile HIV acquisition. One hour after sex there were dramatic increases in penile IL-8 and MIG levels, regardless of condom use, with a gradual return to baseline by 72 hours; similar patterns were observed for other chemoattractant chemokines. Penile cytokine changes were similar in circumcised and uncircumcised men, and repeated measures ANOVA and ANCOVA models demonstrated that the degree of change after condomless sex was explained by cytokine levels in their partners’ cervico-vaginal secretions. This may have important implications for the biology of penile HIV acquisition.Author summaryIn heterosexual men, the penis is the primary site of Human Immunodeficiency Virus (HIV) acquisition. Levels of inflammatory cytokines in the coronal sulcus are associated with an increased HIV risk, and we hypothesized that these may be altered after insertive penile sex. Therefore, we designed the Sex, Couples and Science Study (SECS study) to define the impact of penile-vaginal sex on the penile immune correlates of HIV susceptibility. We found that multiple coronal sulcus cytokines increased dramatically and rapidly after sex, regardless of condom use, with a return to baseline levels by 72 hours. The changes observed after condomless sex were strongly predicted by cytokine concentrations in the vaginal secretions of the female partner, and were similar in circumcised and uncircumcised men. We believe that these findings have important implications for understanding the immunopathogenesis of penile HIV acquisition; in addition, they have important implications for the design of clinical studies of penile HIV acquisition and prevention.

Influence of NKG2C Genotypes on HIV Susceptibility and Viral Load Set Point

NKG2C is an activating NK cell receptor encoded by a gene having an unexpressed deletion variant. Cytomegalovirus (CMV) infection expands a population of NKG2C + NK cells with adaptive-like properties. Previous reports found that carriage of the deleted NKG2C - variant was more frequent in people living with HIV (PLWH) than in HIV - controls unexposed to HIV. The frequency of NKG2C + NK cells positively correlated with HIV viral load (VL) in some studies and negatively correlated with VL in others. Here, we investigated the link between NKG2C genotype and HIV susceptibility and VL set point in PLWH. NKG2C genotyping was performed on 434 PLWH and 157 HIV exposed seronegative (HESN) subjects. Comparing the distribution of the three possible NKG2C genotypes in these populations revealed that the frequency of NKG2C +/+ and NKG2C +/- carriers did not differ significantly between PLWH and HESN subjects, while that of NKG2C -/- carriers was higher in PLWH than in HESNs, in which none were found (p=0.03, χ 2 test). We were unable to replicate that carriage of at least 1 NKG2C - allele was more frequent in PLWH. Information on the pre-treatment VL set point was available for 160 NKG2C +/+ , 83 NKG2C +/- and 6 NKG2C -/- PLWH. HIV VL set point was similar between NKG2C genotypes. The frequency of NKG2C + CD3 - CD14 - CD19 - CD56 dim NK cells and the mean fluorescence intensity (MFI) of NKG2C expression on NK cells was higher on cells from CMV + PLWH who carried 2, versus 1, NKG2C + alleles. We observed no correlations between VL set point and either the frequency or the MFI of NKG2C expression. IMPORTANCE We compared NKG2C allele and genotype distributions in subjects who remained HIV uninfected despite multiple HIV exposures (HESNs) with those in PLWH. This allowed us to determine whether NKG2C genotype influenced susceptibility to HIV infection. The absence of the NKG2C -/- genotype among HESN subjects but not PLWH suggested that carriage of this genotype was associated with HIV susceptibility. We calculated the VL set point in a subset of 252 NKG2C genotyped PLWH. We observed no between-group differences in the VL set point in carriers of the three possible NKG2C genotypes. No significant correlations were seen between the frequency or MFI of NKG2C expression on NK cells with VL set point in cytomegalovirus co-infected PLWH. These findings suggested that adaptive NK cells played no role in establishing the in VL set point, a parameter that is a predictor of the rate of treatment-naïve HIV disease progression.

Vaginal microbiome-hormonal contraceptive interactions associate with the mucosal proteome and HIV acquisition

Alterations to the mucosal environment of the female genital tract, such as genital inflammation, have been associated with increased HIV acquisition in women. As the microbiome and hormonal contraceptives can affect vaginal mucosal immunity, we hypothesized these components may interact in the context of HIV susceptibility. Using previously published microbiome data from 685 women in the CAPRISA-004 trial, we compared relative risk of HIV acquisition in this cohort who were using injectable depot medroxyprogesterone acetate (DMPA), norethisterone enanthate (NET-EN), and combined oral contraceptives (COC). In women who were Lactobacillus-dominant, HIV acquisition was 3-fold higher in women using DMPA relative to women using NET-EN or COC (OR: 3.27; 95% CI: 1.24–11.24, P = 0.0305). This was not observed in non-Lactobacillus-dominant women (OR: 0.95, 95% CI: 0.44–2.15, P = 0.895) (interaction P = 0.0686). Higher serum MPA levels associated with increased molecular pathways of inflammation in the vaginal mucosal fluid of Lactobacillus-dominant women, but no differences were seen in non-Lactobacillus dominant women. This study provides data suggesting an interaction between the microbiome, hormonal contraceptives, and HIV susceptibility.

The Role of Stress and Genital Immunity in Sexual Trauma and HIV Susceptibility Among Adolescent Girls and Adult Women (The THRIVE Study): Protocol for a Longitudinal Case-Control Study

Background The relationship between sexual violence and HIV risk has been extensively documented through social and behavioral research; however, the underlying biological mechanisms are poorly understood. Objective The purpose of the THRIVE (Trauma and HIV Risk: Investigating Stress and the Immune Disruption of the Vaginal Environment) Study is to examine the impact of sexual trauma due to sexual violence on HIV susceptibility through dysregulation of soluble inflammatory and anti-inflammatory and anti-HIV biomarkers in the female genital tract and dysregulation of the hypothalamic-pituitary-adrenal axis among adolescent girls and adult women. Methods The THRIVE Study is a longitudinal case-control study conducted in San Diego, CA, among a racially diverse sample. Cases are adolescent girls (aged 14-19 years) or adult women (aged 20-45 years) who have experienced forced vaginal penetration by a phallus perpetrated by a man within the past 15 days. Controls are adolescent girls or adult women who have engaged in consensual vaginal sex with a man within the past 15 days. At baseline and 1- and 3-month follow-up study visits, participants undergo a urine-based pregnancy test; venipuncture blood draw for HIV, C-reactive protein, adrenocorticotropic hormone, and progesterone testing; a 45-min interviewer-administered computer survey; and cervicovaginal lavage to measure proinflammatory and anti-inflammatory and anti-HIV soluble immune biomarkers. After each study visit, participants self-collect saliva specimens (upon waking, 30 min after waking, and 45 min after waking) at home for 3 consecutive days, which are later assayed for cortisol and dehydroepiandrosterone sulfate. Participants receive compensation at each study visit and for the return of saliva specimens, and a list of local medical and support services. Study procedures use trauma-informed care methods, given the sensitive nature of the study and enrollment of women in the acute phase after sexual trauma. All research staff and investigators adhere to ethical principles and guidelines in the conduct of research activities. Data will be analyzed for descriptive and inferential analyses. Results The recruitment of participants is ongoing. The publication of the first results is expected by late 2021. Conclusions The THRIVE Study will provide foundational knowledge on how sexual trauma due to sexual violence increases susceptibility to HIV acquisition via alterations in cervicovaginal immune regulation and the psychobiology of the stress responses. These findings will inform future research on mechanistic models of in vitro and in vivo injury and cervicovaginal wound healing processes, which may lead to the development of nonvaccine biomedical HIV prevention products for girls and women. International Registered Report Identifier (IRRID) DERR1-10.2196/18190