Cervical human papillomavirus (HPV) infection may increase HIV risk. Since other genital infections enhance HIV susceptibility by inducing inflammation, we assessed the impact of HPV infection and ...clearance on genital immunology and the cervico-vaginal microbiome. Genital samples were collected from 65 women for HPV testing, immune studies and microbiota assessment; repeat HPV testing was performed after 6 months. All participants were HIV-uninfected and free of bacterial STIs. Cytobrush-derived T cell and dendritic cell subsets were assessed by multiparameter flow cytometry. Undiluted cervico-vaginal secretions were used to determine cytokine levels by multiplex ELISA, and to assess bacterial community composition and structure by 16S rRNA gene sequence analysis. Neither HPV infection nor clearance were associated with broad differences in cervical T cell subsets or cytokines, although HPV clearance was associated with increased Langerhans cells and HPV infection with elevated IP-10 and MIG. Individuals with HPV more frequently had a high diversity cervico-vaginal microbiome (community state type IV) and were less likely to have an L. gasseri predominant microbiome. In summary, HPV infection and/or subsequent clearance was not associated with inflammation or altered cervical T cell subsets, but associations with increased Langerhans cells and the composition of the vaginal microbiome warrant further exploration.
Background. Genital inflammation is a key determinant of human immunodeficiency virus (HIV) transmission, and may increase HIV-susceptible target cells and alter epithelial integrity. Several genital ...conditions that increase HIV risk are more prevalent in African, Caribbean, and other black (ACB) women, including bacterial vaginosis and herpes simplex virus type-2 (HSV-2) infection. Therefore, we assessed the impact of the genital microbiota on mucosal immunology in ACB women and microbiome-HSV-2 interactions. Methods. Cervicovaginal secretions and endocervical cells were collected by cytobrush and Instead Softcup, respectively. T cells and dendritic cells were assessed by flow cytometry, cytokines by multiplex enzyme-linked immunosorbent assay (ELISA), and the microbiota by 16S ribosomal ribonucleic acid gene sequencing. Results. The cervicovaginal microbiota of 51 participants were composed of community state types (CSTs) showing diversity (20/51; 39%) or predominated by Lactobacillus iners (22/51; 42%), L. crispatus (7/51; 14%), or L. gasseri (2/51; 4%). High-diversity CSTs and specific bacterial phyla (Gardnerella vaginalis and Prevotella bivia) were strongly associated with cervicovaginal inflammatory cytokines, but not with altered endocervical immune cells. However, cervical CD4+ T-cell number was associated with HSV-2 infection and a distinct cytokine profile. Conclusions. This suggests that the genital microbiota and HSV-2 infection may influence HIV susceptibility through independent biological mechanisms.
Interleukin-22 (IL-22) is a cytokine with epithelial reparative and regenerative properties that is produced by Th22 cells and by other immune cell subsets. Therefore, we explored the hypothesis that ...disruption of the gut barrier during HIV infection involves dysregulation of these cells in the gastrointestinal mucosa. Sigmoid IL-22-producing T cell and Th22 cells were dramatically depleted during chronic HIV infection, epithelial integrity was compromised, and microbial translocation was increased. These alterations were reversed after long-term antiretroviral therapy. While all mucosal IL-22-producing T-cell subsets were also depleted very early during HIV infection, at these early stages IL-22 production by non-T-cell populations (including NKp44+ cells) was increased and gut epithelial integrity was maintained. Circulating Th22 cells expressed a higher level of the HIV co-receptor/binding molecules CCR5 and α4β7 than CD4+ T-cell subsets in HIV-uninfected participants, but this was not the case after HIV infection. Finally, recombinant IL-22 was protective against HIV and tumor necrosis factor-α-induced gut epithelial damage in a validated in vitro gut epithelial system. We conclude that reduced IL-22 production and Th22 depletion in the gut mucosa are important factors in HIV mucosal immunopathogenesis.
The immunology and microbiota of the female genital tract (FGT) are key determinants of HIV susceptibility. Cervical cytobrush sampling is a relatively non-invasive method permitting the longitudinal ...assessment of endocervical immune cells, but effects on FGT immunology are unknown. Blood, cervico-vaginal secretions and cervical cytobrushes were collected from sexually transmitted infection (STI)-free women at baseline and after either 6 hours or 48 hours. Endocervical immune cell subsets were assessed by flow cytometry, and pro-inflammatory cytokines by multiplex ELISA. The density of Lactobacillus species and key bacterial vaginosis-associated bacterial taxa were determined by qPCR. Paired changes were assessed before and after cytobrush sampling. After 6 hours there were significant increases in CD4 + T cell, antigen presenting cell (APC) and neutrophil numbers; APC elevations persisted at 48 hours, while neutrophil and CD4 + T cell numbers returned to baseline. In addition, pro-inflammatory cytokine levels were increased at 6 hours and returned to baseline by 48 hours. No significant changes were observed in the absolute abundance of Lactobacillus species or BV-associated bacteria at either time point. Overall, cytobrush sampling altered genital immune parameters at 6 hours, but only APC number increases persisted at 48 hours. This should be considered in longitudinal analyses of FGT immunology.
A better understanding of the cellular targets of HIV infection in the female genital tract may inform HIV prevention efforts. Proposed correlates of cellular susceptibility include the HIV ...co-receptor CCR5, peripheral homing integrins, and immune activation. We used a CCR5-tropic pseudovirus to quantify HIV entry into unstimulated endocervical CD4(+) T cells collected by cytobrush. Virus entry was threefold higher into cervix-derived CD4(+) T cells than blood, but was strongly correlated between these two compartments. Cervix-derived CD4(+) T cells expressing CD69, α(4)β(7), or α(4)β(1) were preferential HIV targets; this enhanced susceptibility was strongly correlated with increased CCR5 expression in α(4)β(7)(+) and CD69(+) CD4(+) T cells, and to a lesser extent in α(4)β(1)(+) CD4(+) T cells. Direct binding of gp140 to integrins was not observed, integrin inhibitors had no effect on virus entry, and pseudotypes with an env that preferentially binds α(4)β(7) still demonstrated enhanced entry into α(4)β(1)(+) cells. In summary, a rapid and sensitive HIV entry assay demonstrated enhanced susceptibility of activated endocervical CD4(+) T cells, and those expressing α(4)β(7) or α(4)β(1). This may relate to increased CCR5 expression by these cell subsets, but did not appear to be due to direct interaction of α(4)β(7) or α(4)β(1) with HIV envelope.
Early and profound CD4+ T-cell depletion in gut-associated lymphoid tissue (GALT) may drive Human Immunodeficiency Virus (HIV) immunopathogenesis, and GALT immune reconstitution on highly active ...antiretroviral therapy (HAART) may be suboptimal. Blood and sigmoid colon biopsies were collected from HAART-treated individuals with undetectable blood HIV RNA for > or =4 years and from uninfected controls. HIV proviral levels and T-cell phenotype/function were examined in both compartments. CD4+ T-cell reconstitution in the sigmoid, including CD4+ T cells expressing CCR5, exceeded that in blood and did not differ from uninfected controls. Sigmoid HIV proviral load was not correlated with CD4+ reconsitution, but was correlated with the degree of mucosal CD8+ T-cell immune activation. Colonic Gag-specific T-cell responses were common, but were not associated with proviral load or immune activation. In this select study population, long-term HAART was associated with complete CD4+ T-cell reconstitution in sigmoid colon. However, colonic immune activation may drive ongoing HIV replication.
Background: The penis is the primary site of HIV acquisition in heterosexual men. The per-act probability of HIV acquisition is enhanced by the presence of a foreskin, sexually transmitted infections ...(STIs) and/or microbiome dysbiosis, with elevated penile inflammatory cytokines acting as a common central pathway. However, the impact of sex itself on the penile immune milieu is unknown. We hypothesized that condomless penile-vaginal sex would transiently increase penile cytokines, with increases being more profound and sustained in uncircumcised men. Methods: To address this hypothesis we recruited 37 STI-free heterosexual couples to the Sex, Couples and Science Study (SECS), an observational prospective study ran from July to November 2018 through the Women's Health in Women's Hands Clinic (Toronto, Canada). Approximately half of the male partners were circumcised. Baseline penile swabs, semen samples, cervical secretions and blood were collected after a period of abstinence, and 48 hours later couples engaged in either condomless (n=30) or condom-protected (n=8) penile-vaginal sex. One couple participated twice, once in each group. Repeat penile swabs and blood were collected after one to two hours, seven to eight hours and fourty-eight to seventy-two hours. Soluble immune factors were quantified by multiplex immunoassay, and blood immune cell subsets were determined by flow cytometry; the study co-primary immune endpoints were the penile levels of IL-8 and MIG, cytokines previously linked to HIV acquisition. Statistical comparisons were performed using the Wilcoxon Signed Ranked test. Results: One hour after sex there was a dramatic increase in coronal sulcus levels of IL-8 and MIG, regardless of condom use, with a return to baseline by 72 hours; similar patterns were observed for other chemoattractant chemokines. The extent and duration of these increases were similar in circumcised and uncircumcised men, and correlated closely with cytokine levels in the female partner's genital tract (after condomless sex) or in the participant's semen (after condom-protected sex). Conclusions: Relatively sustained increases in penile inflammatory cytokines after penile-vaginal sex appear to reflect penile coating with cervico-vaginal secretions and/or semen. Since external application of cytokines enhanced HIV acquisition in a foreskin explant model, these novel findings have important implications for the biology of penile HIV acquisition.
There is substantial epidemiological evidence that infection by Herpes simplex virus type 2 (HSV2) enhances both HIV susceptibility and subsequent sexual transmission. Both infections are extremely ...common in female sex workers (FSWs) in sub-Saharan Africa, and up to 80% of new HIV infections in urban men in the region are acquired via transactional sex. The present study aimed to elucidate the mucosal immune interactions between HIV and HSV2 in the genital tract.
Endocervical immune cell populations, cytokine/chemokine protein levels in cervico-vaginal secretions and cervical immune gene expression profiles were measured in a well-defined cohort of HIV-infected and uninfected Kenyan FSWs. Associations between the genital immune milieu and infection by and/or shedding of common genital co-pathogens were examined.
HIV-infected FSWs were much more likely to be infected by HSV2, and to shed HSV2 DNA in the genital tract. There was also a profound negative 'mucosal synergy' between these viruses. In HIV uninfected FSWs, HSV2 infection was associated with a ten-fold increase in cervical immature dendritic cells (iDC) expressing DC-SIGN, and a three-fold increase in cervical CD4+ T cells expressing CCR5. HIV infection was associated with iDC depletion in the cervix, and with increased HSV2 genital reactivation, which in turn was associated with HIV shedding levels.
The findings suggest a mucosal vicious circle in which HSV2 infection increases HIV target cells in the genital mucosa, subsequent HIV infection impairs HSV2 mucosal immune control, and local HSV2 reactivation enhances both HSV2 and HIV transmission.
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