Recruitment of CD4 T lymphocytes and macrophages into the cervical epithelium of women after coitus

The use of PSA as a biomarker of recent semen exposure in female reproductive health studies

Semen contains potent soluble proteins, bacteria, viruses, activated immune cells as well as anti- and pro-inflammatory cytokines that may influence the inflammatory response and alter microbial composition of the female genital tract. The presence of semen in the female genital mucosa may be a significant confounder that most studies have failed to control for in their analysis. Prostate-specific antigen (PSA), a protein secreted by the prostate into the urethra during ejaculation, is a well-established biomarker of semen exposure. Several studies have demonstrated discordance between self-reports of sexual behavior and the presence of PSA. Recent semen exposure has been shown to promote pro-inflammatory responses, stimulate the recruitment of activated immune cells and decrease Lactobacilli abundance in the female genital mucosa. As a result, it is important to understand the concordance between self-reported consistent condom use and the presence of semen biomarkers. Furthermore, to ensure that the interpretation of data in clinical studies of the immunological and microbial environment in the female genital mucosa are accurate, it is essential to establish whether semen is present in the vaginal fluid. This review explores the impact of semen exposure on the mucosal microenvironment and assesses the use of the PSA as an objective biomarker of semen exposure to reduce reliance on self-reported sexual intercourse.

Initiation of Antiretroviral Therapy Differentially Influences Genital and Systemic Immune Activation in HIV-Infected Women

Antiretroviral therapy (ART) has significantly improved the quality of life of HIV-infected individuals: reducing plasma viremia, restoring CD4⁺ T cell numbers, and correcting imbalances in blood memory T cell subsets. While ART improves immune correlates at mucosal sites, including the lower female genital tract (FGT), ART initiation has been associated with reactivation of common FGT infections. We investigated the effect of ART on immune activation and inflammation in the genital tract. We measured blood and genital T cell activation, proliferation, and immunosenescence (CD38, HLADR, Ki67, CD127, and CD57), and cytokine levels in women on ART for ∼7 years (cross-sectional analysis) or initiating ART (immediately before and 1 month after). Effector memory T cells predominated in blood and FGT during chronic infection, irrespective of ART status. In women initiating ART, 1 month was insufficient for T cell reconstitution, or alterations in T cell subset distribution, despite both plasma and genital viral loads decreasing to undetectable levels in most participants. Initiating ART was accompanied by a decline in plasma IP-10 that correlated with decreased blood CD38 expression in blood (p = .0204) but not in the FGT. The reduction in plasma (but not genital) cytokine levels due to ART initiation was dependent on their concentrations before treatment. While T cell activation decreased significantly in blood (CD4: p = .032; CD8: p = .0137), activation levels remained similar in the genital tract despite 1 month of treatment. Overall, the decrease in cellular activation and inflammation seen in blood with ART initiation was not evident in the FGT.

Inflammatory Cytokine Profiles of Semen Influence Cytokine Responses of Cervicovaginal Epithelial Cells

Genital inflammatory cytokine responses increase HIV risk. Since male partner semen is a complex mixture of immune-modulatory prostaglandins and cytokines, we hypothesized that exposure to semen may influence genital inflammation in women. Here, we investigated cytokine response kinetics of cervical cells following stimulation with seminal plasma from HIV-negative and HIV-positive men characterized as having low or high concentrations of inflammatory cytokines. Irrespective of the HIV status or semen cytokine profile, in vitro stimulation of cervical cells with seminal plasma resulted in significantly elevated concentrations of secreted IL-6, IL-8, TNF-β, MCP-1, GM-CSF, and VEGF within 8 h of stimulation, which tended to decline by 24 h, although this was only significant for TNF-β. Consistent with this, cervical cells responded to seminal plasma with increases in IL-8 and IL-1β mRNA expression of 10-fold. These findings suggest that the impact of semen on local female genital cytokines is likely transient. Although these findings suggest that the impact of semen on local female genital cytokines may not be sustained long-term, this heightened genital inflammation may have implications for HIV risk in women.

Vaginal lactic acid elicits an anti-inflammatory response from human cervicovaginal epithelial cells and inhibits production of pro-inflammatory mediators associated with HIV acquisition

Inflammation in the female reproductive tract (FRT) is associated with increased HIV transmission. Lactobacillus spp. dominate the vaginal microbiota of many women and their presence is associated with reduced HIV acquisition. Here we demonstrate that lactic acid (LA), a major organic acid metabolite produced by lactobacilli, mediates anti-inflammatory effects on human cervicovaginal epithelial cells. Treatment of human vaginal and cervical epithelial cell lines with LA (pH 3.9) elicited significant increases in the production of the anti-inflammatory cytokine IL-1RA. When added simultaneously or prior to stimulation, LA inhibited the Toll-like receptor agonist-elicited production of inflammatory mediators IL-6, IL-8, TNFα, RANTES, and MIP3α from epithelial cell lines and prevented IL-6 and IL-8 production by seminal plasma. The anti-inflammatory effect of LA was mediated by the protonated form present at pH≤3.86 and was observed with both L- and D-isomers. A similar anti-inflammatory effect of LA was observed in primary cervicovaginal cells and in an organotypic epithelial tissue model. These findings identify a novel property of LA that acts directly on epithelial cells to inhibit FRT inflammation and highlights the potential use of LA-containing agents in the lower FRT as adjuncts to female-initiated strategies to reduce HIV acquisition.

Epithelium-innate immune cell axis in mucosal responses to SIV

In the SIV (simian immunodeficiency virus)-rhesus macaque model of HIV-1 (human immunodeficiency virus type I) transmission to women, one hallmark of the mucosal response to exposure to high doses of SIV is CD4 T-cell recruitment that fuels local virus expansion in early infection. In this study, we systematically analyzed the cellular events and chemoattractant profiles in cervical tissues that precede CD4 T-cell recruitment. We show that vaginal exposure to the SIV inoculum rapidly induces chemokine expression in cervical epithelium including CCL3, CCL20, and CXCL8. The chemokine expression is associated with early recruitment of macrophages and plasmacytoid dendritic cells that are co-clustered underneath the cervical epithelium. Production of chemokines CCL3 and CXCL8 by these cells in turn generates a chemokine gradient that is spatially correlated with the recruitment of CD4 T cells. We further show that the protection of SIVmac239Δnef vaccination against vaginal challenge is correlated with the absence of this epithelium-innate immune cell-CD4 T-cell axis response in the cervical mucosa. Our results reveal a critical role for cervical epithelium in initiating early mucosal responses to vaginal infection, highlight an important role for macrophages in target cell recruitment, and provide further evidence of a paradoxical dampening effect of a protective vaccine on these early mucosal responses.

Friend or Foe: Innate Sensing of HIV in the Female Reproductive Tract

The female reproductive tract (FRT) is a major site for human immunodeficiency virus (HIV) infection. There currently exists a poor understanding of how the innate immune system is activated upon HIV transmission and how this activation may affect systemic spread of HIV from the FRT. However, multiple mechanisms for how HIV is sensed have been deciphered using model systems with cell lines and peripheral blood-derived cells. The aim of this review is to summarize recent progress in the field of HIV innate immune sensing and place this in the context of the FRT. Because HIV is somewhat unique as an STD that thrives under inflammatory conditions, the response of cells upon sensing HIV gene products can either promote or limit HIV infection depending on the context. Future studies should include investigations into how FRT-derived primary cells sense and respond to HIV to confirm conclusions drawn from non-mucosal cells. Understanding how cells of the FRT participate in and effect innate immune sensing of HIV will provide a clearer picture of what parameters during the early stages of HIV exposure determine transmission success. Such knowledge could pave the way for novel approaches for preventing HIV acquisition in women.

Sexual Violence in America: Public Funding and Social Priority

We compared lifetime risk, annual incidence, and annual economic burden of sexual violence with other major public health issues in the United States: cardiovascular disease, cancer, diabetes, and HIV/AIDS. With public funding data from 2013, we examined how much public funding is allocated to these public health issues as a proxy of the social priority of addressing each of them. Although sexual violence is as prevalent as and more costly than are these other major public health issues, it receives a fraction of the public funds that they receive.

Effectiveness of an integrated intimate partner violence and HIV prevention intervention in Rakai, Uganda: analysis of an intervention in an existing cluster randomised cohort

BACKGROUND

Intimate partner violence (IPV) is associated with HIV infection. We aimed to assess whether provision of a combination of IPV prevention and HIV services would reduce IPV and HIV incidence in individuals enrolled in the Rakai Community Cohort Study (RCCS), Rakai, Uganda.

METHODS

We used pre-existing clusters of communities randomised as part of a previous family planning trial in this cohort. Four intervention group clusters from the previous trial were provided standard of care HIV services plus a community-level mobilisation intervention to change attitudes, social norms, and behaviours related to IPV, and a screening and brief intervention to promote safe HIV disclosure and risk reduction in women seeking HIV counselling and testing services (the Safe Homes and Respect for Everyone [SHARE] Project). Seven control group clusters (including two intervention groups from the original trial) received only standard of care HIV services. Investigators for the RCCS did a baseline survey between February, 2005, and June, 2006, and two follow-up surveys between August, 2006, and April, 2008, and June, 2008, and December, 2009. Our primary endpoints were self-reported experience and perpetration of past year IPV (emotional, physical, and sexual) and laboratory-based diagnosis of HIV incidence in the study population. We used Poisson multivariable regression to estimate adjusted prevalence risk ratios (aPRR) of IPV, and adjusted incidence rate ratios (aIRR) of HIV acquisition. This study was registered with ClinicalTrials.gov, number NCT02050763.

FINDINGS

Between Feb 15, 2005, and June 30, 2006, we enrolled 11 448 individuals aged 15-49 years. 5337 individuals (in four intervention clusters) were allocated into the SHARE plus HIV services group and 6111 individuals (in seven control clusters) were allocated into the HIV services only group. Compared with control groups, individuals in the SHARE intervention groups had fewer self-reports of past-year physical IPV (346 [16%] of 2127 responders in control groups vs 217 [12%] of 1812 responders in intervention groups; aPRR 0·79, 95% CI 0·67-0·92) and sexual IPV (261 [13%] of 2038 vs 167 [10%] of 1737; 0·80, 0·67-0·97). Incidence of emotional IPV did not differ (409 [20%] of 2039 vs 311 [18%] of 1737; 0·91, 0·79-1·04). SHARE had no effect on male-reported IPV perpetration. At follow-up 2 (after about 35 months) the intervention was associated with a reduction in HIV incidence (1·15 cases per 100 person-years in control vs 0·87 cases per 100 person-years in intervention group; aIRR 0·67, 95% CI 0·46-0·97, p=0·0362).

INTERPRETATION

SHARE could reduce some forms of IPV towards women and overall HIV incidence, possibly through a reduction in forced sex and increased disclosure of HIV results. Findings from this study should inform future work toward HIV prevention, treatment, and care, and SHARE's ecological approach could be adopted, at least partly, as a standard of care for other HIV programmes in sub-Saharan Africa.

FUNDING

Bill & Melinda Gates Foundation, US National Institutes of Health, WHO, President's Emergency Plan for AIDS Relief, Fogarty International Center.

Effect of female genital schistosomiasis and anti-schistosomal treatment on monocytes, CD4+ T-cells and CCR5 expression in the female genital tract

Background

Schistosoma haematobium is a waterborne parasite that may cause female genital schistosomiasis (FGS), characterized by genital mucosal lesions. There is clinical and epidemiological evidence for a relationship between FGS and HIV. We investigated the impact of FGS on HIV target cell density and expression of the HIV co-receptor CCR5 in blood and cervical cytobrush samples. Furthermore we evaluated the effect of anti-schistosomal treatment on these cell populations.

Design

The study followed a case-control design with post treatment follow-up, nested in an on-going field study on FGS.

Methods

Blood and cervical cytobrush samples were collected from FGS negative and positive women for flow cytometry analyses. Urine samples were investigated for schistosome ova by microscopy and polymerase chain reaction (PCR).

Results

FGS was associated with a higher frequency of CD14⁺ cells (monocytes) in blood (11.5% in FGS+ vs. 2.2% in FGS-, p = 0.042). Frequencies of CD4⁺ cells expressing CCR5 were higher in blood samples from FGS+ than from FGS- women (4.7% vs. 1.5%, p = 0.018). The CD14⁺ cell population decreased significantly in both compartments after anti-schistosomal treatment (p = 0.043). Although the frequency of CD4+ cells did not change after treatment, frequencies of CCR5 expression by CD4+ cells decreased significantly in both compartments (from 3.4% to 0.5% in blood, p = 0.036; and from 42.4% to 5.6% in genital samples, p = 0.025).

Conclusions

The results support the hypothesis that FGS may increase the risk of HIV acquisition, not only through damage of the mucosal epithelial barrier, but also by affecting HIV target cell populations, and that anti-schistosomal treatment can modify this.

Prostaglandins in semen compromise the immune response against sexually transmitted pathogens

Seminal plasma is not just a spermatozoa carrier. It induces the expression of inflammatory cytokines and chemokines and a massive infiltration of neutrophils, monocytes and dendritic cells in the female genital mucosa after coitus, enabling the innate immune system to fight against sexually transmitted pathogens. However, exposure to seminal plasma not only turns on an inflammatory response but also induces regulatory mechanisms that allow the fetus (a semiallograft) to grow and develop in the uterus. In mouse models it has been shown that seminal plasma induces the expansion of regulatory T cells specific to seminal Ags in the receptive partner, thus promoting tolerance to paternal alloantigens and avoiding allogeneic fetal rejection. These mechanisms appear to be mainly induced by prostaglandins of the E series (PGE) and TGF-β, which are present at huge concentrations in the seminal plasma. Moreover, we have recently shown that exposure to seminal plasma induces the differentiation of dendritic cells into a tolerogenic profile through a mechanism dependent on the activation of the prostanoid receptors EP2 and EP4 by seminal PGE. Our hypothesis proposes that this tolerogenic response induced by seminal PGE, while promoting fertility by inducing tolerance toward paternal alloantigens, might also compromise the development of the adaptive immune response against sexually transmitted pathogens in the receptive partner.

Association of sex work with reduced activation of the mucosal immune system

BACKGROUND

Unprotected intercourse and seminal discharge are powerful activators of the mucosal immune system and are important risk factors for transmission of human immunodeficiency virus (HIV). This study was designed to determine if female sex work is associated with changes in the mucosal immunity.

METHODS

Cervicovaginal lavage and plasma from 122 HIV-uninfected female sex workers (FSW) and 44 HIV-uninfected low-risk non-FSW from the same socioeconomic district of Nairobi were analyzed for evidence of immune activation (IA). The cervico-mononuclear cells (CMC) were analyzed for cellular activation by flow cytometry.

RESULTS

Lower IA was observed in FSW compared to the low-risk women as demonstrated by the lower level of MIP-3α (P < .001), ITAC (P < .001), MIG (p.0001), IL-1α (P < .001), IL-1β (P < .001), IL-1Rα (P = .0002), IL-6 (P < .001), IL-8 (P < .001), IL-10 (P = .01), IP-10 (P = .0001), MDC (P < .001), MIP-1α, (P < .001), MIP-1β (P = .005), MCP-1 (P = .03), and TNF-α (P = .006). Significant differences were noted as early as 1 year following initiation of sex work and increased with duration of sex work.

CONCLUSION

This study showed that sex work is associated with important changes in the mucosal immune system. By analyzing chemokine/cytokine levels and CMC activation, we observed a lower mucosal IA in HIV-uninfected FSW compared to low-risk women.

HIV, sexual violence and special populations: adolescence and pregnancy

The risk of male to female transmission of HIV is impacted by baseline inflammation in the female genital tract, semen viral load and seminal plasma's ability to induce specific patterns of cervical cytokine signalling and influx of immune cell populations. Disruption of the epithelial barrier during non-consensual intercourse may trigger further inflammation and initiation of cell-signalling pathways, thus facilitating transmission of HIV and expansion of local infection. Adolescent and pregnant women are at high risk for sexual violence and may exhibit alterations of genital mucosal immunity that promote immune activation, making them uniquely vulnerable to HIV acquisition.

HIV-1 co-receptor expression and epithelial immune cells of the cervix in asymptomatic women attending a genitourinary medicine clinic

OBJECTIVES

The aim of the study was to qualitatively and semiquantitatively characterize the expression of the principal HIV co-receptors chemokine (C-C motif) receptor 5 (CCR5) and chemokine (C-X-C motif) receptor 4 (CXCR4) on susceptible CD4 T-helper cell, monocyte/macrophage and Langerhans dendritic cell populations within the cervical epithelia of asymptomatic women attending a genitourinary medicine clinic.

METHODS

Of 77 asymptomatic women recruited, 35 were excluded: 21 because they were found to have bacterial vaginosis, eight because they were found to have candida and six for other reasons. Cervical cytobrush samples from 11 women with Chlamydia trachomatis infection and 31 women without any detectable genital infection were stained with fluorescently labelled antibodies specific for cell surface CCR5, CXCR4, CD4, CD3, CD1a and CD19 expression, then analysed by flow cytometry.

RESULTS

CD4/CD3 T-helper cells (84%), CD1a Langerhans dendritic cells (75%) and CD4/CD14 monocytes/macrophages (59%) were detected in the samples. CCR5 and CXCR4 HIV co-receptor expression was observed on 46-86% of the above subsets. CD1a cells exhibited significantly higher CCR5 and CXCR4 positivity and median fluorescence than CD4 cells and higher CXCR4 positivity and median fluorescence than CD14 cells (P < 0.05 or less). Increased detection of CCR5 over CXCR4 was seen in CD14 cells (P < 0.05). No significant differences in CCR5 or CXCR4 expression were found in samples from asymptomatic women with or without chlamydial infection.

CONCLUSIONS

Co-receptor expression confirms the potential for CD1a Langerhans cells, monocytes/macrophages and T-helper cells in the cervix as primary targets for HIV infection. Previously observed selective transmission of CCR5-tropic isolates cannot be accounted for by a lack of CXCR4-expressing CD4 cervical immune cells. We were unable to identify any specific impact of chlamydial infection on co-receptor expression in this study.

Forced sex and HIV risk in violent relationships

PROBLEM

The intersecting epidemics of gender-based violence, specifically forced sex, and HIV continue to affect women worldwide. Both in the United States and worldwide, women of African descent are disproportionately affected.

METHOD OF STUDY

The current literature was reviewed for inclusion based on its relevance to the intersection of forced sex and HIV risk behaviors.

RESULTS

This brief review synthesizes research on the linkages between forced sex and behavioral risk factors for HIV infection. We explore forced sex from the perspective of the perpetrator being a current or former intimate partner, as well as the first sexual intercourse experience occurring through the use of physical force (i.e., forced sexual initiation). The review also emphasizes the importance of expanding current research to understand the physiological mechanisms linking forced sex to HIV risk.

CONCLUSION

The factors linking intimate partner forced sex and forced sexual initiation with HIV/AIDS are varied and complex. The review concludes with recommendations for future research in this area and implications this research could have on preventing violence and mitigating the health consequences.

Semen promotes the differentiation of tolerogenic dendritic cells

Seminal plasma is not just a carrier for spermatozoa. It contains high concentrations of cytokines, chemokines, and other biological compounds that are able to exert potent effects on the immune system of the receptive partner. Previous studies have shown that semen induces an acute inflammatory response at the female genital mucosa after coitus. Moreover, it induces regulatory mechanisms that allow the fetus (a semiallograft) to grow and develop in the uterus. The mechanisms underlying these regulatory mechanisms, however, are poorly understood. In this study, we show that seminal plasma redirects the differentiation of human dendritic cells (DCs) toward a regulatory profile. DCs differentiated from human monocytes in the presence of high dilutions of seminal plasma did not express CD1a but showed high levels of CD14. They were unable to develop a fully mature phenotype in response to LPS, TNF-α, CD40L, Pam2CSK4 (TLR2/6 agonist), or Pam3CSK4 (TLR1/2 agonist). Upon activation, they produced low amounts of the inflammatory cytokines IL-12p70, IL-1β, TNF-α, and IL-6, but expressed a high ability to produce IL-10 and TGF-β. Inhibition of the PG receptors E-prostanoid receptors 2 and 4 prevented the tolerogenic effect induced by seminal plasma on the phenotype and function of DCs, suggesting that E-series PGs play a major role. By promoting a tolerogenic profile in DCs, seminal plasma might favor fertility, but might also compromise the capacity of the receptive partner to mount an effective immune response against sexually transmitted pathogens.

Seminal fluid induces leukocyte recruitment and cytokine and chemokine mRNA expression in the human cervix after coitus

In mice, seminal fluid elicits an inflammation-like response in the female genital tract that activates immune adaptations to advance the likelihood of conception and pregnancy. In this study, we examined whether similar changes in leukocyte and cytokine parameters occur in the human cervix in response to the male partner's seminal fluid. After a period of abstinence in proven-fertile women, duplicate sets of biopsies were taken from the ectocervix in the periovulatory period and again 48 h later, 12 h after unprotected vaginal coitus, vaginal coitus with use of a condom, or no coitus. A substantial influx of CD45(+) cells mainly comprising CD14(+) macrophages and CD1a(+) dendritic cells expressing CD11a and MHC class II was evident in both the stratified epithelium and deeper stromal tissue after coitus. CD3(+)CD8(+)CD45RO(+) T cells were also abundant and increased after coitus. Leukocyte recruitment did not occur without coitus or with condom-protected coitus. An accompanying increase in CSF2, IL6, IL8, and IL1A expression was detected by quantitative RT-PCR, and microarray analysis showed genes linked with inflammation, immune response, and related pathways are induced by seminal fluid in cervical tissues. We conclude that seminal fluid introduced at intercourse elicits expression of proinflammatory cytokines and chemokines, and a robust recruitment of macrophages, dendritic cells, and memory T cells. The leukocyte and cytokine environment induced in the cervix by seminal fluid appears competent to initiate adaptations in the female immune response that promote fertility. This response is also relevant to transmission of sexually transmitted pathogens and potentially, susceptibility to cervical metaplasia.

Herpes simplex virus-induced epithelial damage and susceptibility to human immunodeficiency virus type 1 infection in human cervical organ culture

Normal human premenopausal cervical tissue has been used to derive primary cell populations and to establish ex vivo organ culture systems to study infections with herpes simplex virus (HSV-1 or HSV-2) and human immunodeficiency virus type 1 (HIV-1). Infection with either HSV-1 or HSV-2 rapidly induced multinuclear giant cell formation and widespread damage in mucosal epithelial cells. Subsequent exposure of the damaged mucosal surfaces to HIV-1 revealed frequent co-localization of HSV and HIV-1 antigens. The short-term organ culture system provides direct experimental support for the epidemiological findings that pre-existing sexually transmitted infections, including primary and recurrent herpes virus infections at mucosal surfaces, represent major risk factors for acquisition of primary HIV-1 infection. Epithelial damage in combination with pre-existing inflammation, as described here for overtly normal human premenopausal cervix, creates a highly susceptible environment for the initiation and establishment of primary HIV-1 infection in the sub-mucosa of the cervical transformation zone.

Coming of age: reconstruction of heterosexual HIV-1 transmission in human ex vivo organ culture systems

Heterosexual transmission of human immunodeficiency virus-1 (HIV-1), from men to women, involves exposure to infectious HIV-1 in semen. Therefore, the cellular and molecular processes that underlie HIV-1 transmission are closely interconnected with fundamental principles of human reproductive biology. Human ex vivo organ culture systems allow experimental reconstruction of HIV-1 transmission, using human semen and premenopausal cervicovaginal mucosal tissue, with specific emphasis on the progression from exposure to development of primary HIV-1 infection. Clearly, an isolated piece of human tissue cannot duplicate the full complexity of events in natural infections, but with correct observation of conventional medical and ethical standards, there is no opportunity to study HIV-1 exposure and primary infection in young women. Human mucosal organ cultures allow direct study of HIV-1 infection in a reproducible format while retaining major elements of complexity and variability that typify community-based HIV-1 transmission. Experimental manipulation of human mucosal tissue both allows and requires acquisition of new insights into basic processes of human mucosal immunology. Expanding from the current foundations, we believe that human organ cultures will become increasingly prominent in experimental studies of HIV-1 transmission and continuing efforts to prevent HIV-1 infection at human mucosal surfaces.

Cervicovaginal shedding of HIV type 1 is related to genital tract inflammation independent of changes in vaginal microbiota

We examined the relationship of proinflammatory vaginal cytokines and secretory leukocyte protease inhibitor (SLPI) with genital HIV-1 shedding after controlling for genital coinfections. Fifty-seven HIV-1-infected women in Seattle, WA (n = 38) and Rochester, NY (n = 19) were followed every 3-4 months for a total of 391 visits. At each visit, plasma and cervicovaginal lavage (CVL) were tested for HIV-1 RNA using qPCR. Vaginal samples were tested for bacterial vaginosis, yeast, hydrogen peroxide-producing Lactobacillus colonization, Trichomonas vaginalis, Neisseria gonorrhea, Chlamydia trachomatis, CMV, and HSV shedding. CVL interleukins (IL)-1β, IL-6, IL-8, and SLPI were measured using ELISA. Linear regression with generalized estimating equations examined effects of cytokine concentrations on CVL HIV-1 RNA, adjusted for plasma HIV RNA, and measured coinfections. CVL IL-1β and IL-8 were significantly associated with CVL HIV-1 RNA. This persisted after adjusting for plasma HIV-1 RNA. Higher levels of IL-1β were associated with higher concentrations of HIV-1 RNA in CVL (β = 0.25, 95% CI 0.09, 0.42), as were higher levels of IL-8 (β = 0.34, 95% CI 0.17, 0.50). Adjusting for the presence of the coinfections described, this relationship was attenuated for IL-1β (β = 0.16; 95% CI -0.01, 0.33) but still significant for IL-8 (β = 0.29; 95% CI 0.13, 0.45). The proinflammatory cytokines IL-1β and IL-8 are associated with higher cervicovaginal HIV-1 RNA concentrations, even after controlling for plasma viral load and vaginal microbial cofactors. This association suggests that there may be additional, noninfectious causes of inflammation that increase cervicovaginal HIV-1 shedding.

Constitutive expression of the antibacterial CXC chemokine GCP-2/CXCL6 by epithelial cells of the male reproductive tract

The reproductive tract is continuously challenged by potential pathogens present in the environment. Therefore, robust host defense mechanisms are essential both for the health of the individual and for fertilization. Antibiotic innate immunity peptides possess broad antimicrobial activity. Recently, we found that the CXC chemokine, granulocyte chemotactic protein (GCP)-2/CXCL6, possesses antibacterial activity. In the present study, we investigated, therefore, the presence of GCP-2/CXCL6 in the human male reproductive system. GCP-2/CXCL6 was detected at 19nM (mean; range: 5-47nM; n=14) in seminal plasma of fertile donors, i.e. at levels more than 100 times higher than those previously reported for the related chemokine IL-8/CXCL8. No GCP-2/CXCL6 could be detected in blood plasma of healthy donors, indicating local production in the male reproductive tract. In vasectomized donors, significantly lower levels of GCP-2/CXCL6 were found (mean: 3nM; range 2-7nM; n=7), demonstrating that the testis and epididymis contribute significantly to the GCP-2/CXCL6 content of seminal plasma. Strong expression of GCP-2/CXCL6 was found in the epithelium of the testis, epididymis and seminal vesicles, while the prostate epithelium showed weak expression, as determined by immunohistochemistry. A biological function is suggested, viz. at concentrations of the order of those found in seminal plasma, GCP-2/CXCL6 has antibacterial activity against the urogenital pathogen Neisseria gonorrhoeae. GCP-2/CXCL6 in seminal plasma may play roles in both host defense of the male urogenital tract and during fertilization.

The antibacterial chemokine MIG/CXCL9 is constitutively expressed in epithelial cells of the male urogenital tract and is present in seminal plasma

The integrity of the urogenital tract against potentially invasive pathogens is important for the health of the individual, fertilization, and continuance of species. Antibiotic peptides with broad antimicrobial activity, among them chemokines, are part of the innate immune system. We investigated the presence of the antibacterial interferon (IFN)-dependent CXC chemokines, MIG/CXCL9, IP-10/CXCL10, and I-TAC/CXCL11, in the human male reproductive system. MIG/CXCL9 was detected at 25.0 nM (range 8.1-40.6 nM; n = 14), whereas IP-10/CXCL10 and I-TAC/CXCL11 were detected at lower levels (mean 1.8 nM, range 0.3-5.8 nM and mean 0.6, 0.2-1.6 nM, respectively) in seminal plasma of fertile donors. The levels of MIG/CXCL9 are more than 300-fold higher than those previously reported in blood plasma. In vasectomized donors, significantly lower levels of MIG/CXCL9 (mean 14.7 nM, range 6.6-21.8) were found, suggesting that the testis and epididymis, in addition to the prostate, significantly contribute to the MIG/CXCL9 content of seminal plasma. Strong expression of MIG/CXCL9 was found in the epithelium of testis, epididymis, and prostate, as detected by immunohistochemistry. MIG/CXCL9 at concentrations in the order of those found in seminal plasma possessed antibacterial activity against the urogenital pathogen Neisseria gonorrhoeae. The relatively high levels of MIG/CXCL9 in seminal plasma point to roles for this chemokine in both host defense of the male urogenital tract and during fertilization.

The genital tract immune milieu: an important determinant of HIV susceptibility and secondary transmission

HIV is generally sexually acquired across the genital or rectal mucosa after exposure to the genital secretions of an HIV-infected partner. Most exposures to HIV do not result in infection, likely due to protection afforded by an intact mucosal epithelium, as well as by innate and adaptive mucosal immune factors present in the genital tract. Another important mucosal determinant of transmission may be the number and activation status of potential HIV target cells, including CCR5/CD4+ T cells and DC-SIGN+ dendritic cells. The simultaneous presence of other genital infections, including classical sexually transmitted infections (STIs), can enhance HIV susceptibility either by breaching the epithelial barrier, recruiting HIV target cells to the genital tract, or by generating a pro-inflammatory local immune milieu. In HIV-infected individuals, genital co-infections increase HIV levels in the genital secretions, thereby increasing secondary sexual transmission. Co-infections that act as important HIV cofactors include human cytomegalovirus (CMV), Herpes simplex virus type 2 (HSV2), Neisseria gonorrhoeae and many others. Strategies focused on genital co-infections, such as vaccines, microbicides and suppressive therapy, are feasible in the short term and have the potential to curb the pandemic.

T-Lymphocyte Profile and Total and Virus-Specific Immunoglobulin Concentrations in the Cervix of HIV-1-Infected Women

BACKGROUND

The mucosal lymphocyte population is the largest in the body, and the gastrointestinal compartment has been well characterized in HIV infection. Much less is known about the effects of HIV on the genital tract.

OBJECTIVE

: To examine the T-lymphocyte phenotype and receptor repertoire as well as total and virus-specific immunoglobulin concentrations in the endocervix of HIV-infected women at different stages of infection as compared with uninfected women.

PATIENTS AND METHODS

Participants were 12 seronegative women, 10 HIV-infected "slow progressors" not taking antiretroviral therapy, and 9 HIV-infected women whose antiretroviral therapy was failing. We used multiparameter flow cytometry to enumerate T-cell populations on cytobrush-obtained cervical specimens, the immunoscope technique to determine the T-cell receptor (TCR) repertoire, and quantitative enzyme-linked immunosorbent assays for antibody determinations on cervical secretions absorbed onto ophthalmic sponges. Nonparametric statistical analyses were performed.

RESULTS

We found marked depletion of leukocytes and CD4 T lymphocytes in the endocervix of HIV-infected women as compared with uninfected women; this was significant at more advanced disease stages. Naive T cells were rare in the endocervix of all groups. Activation marker expression was higher in endocervical T lymphocytes than in peripheral blood among control and slow-progressing HIV-infected women but not in women failing therapy. Endocervical T lymphocytes showed highly restricted utilization of Vbeta TCR families. Unlike other mucosal sites, the cervix contained IgG as the predominant immunoglobulin isotype. HIV-IgG was detected in the cervix of most HIV-infected women and in blood of all infected women.

CONCLUSIONS

HIV infection induces substantial changes in the immune profile of the female genital tract. Further study of the implications of these findings for HIV acquisition and transmission is needed.

R5- and X4-HIV-1 use differentially the endometrial epithelial cells HEC-1A to ensure their own spread: implication for mechanisms of sexual transmission

The mechanism of viral transmission across the mucosal barrier is poorly understood. Using the endometrial epithelium-derived cell line HEC-1A, we found that the cells are capable of sequestering large numbers of HIV-1 particles but are refractory to cell-free viral infection. The removal of heparan sulfate moieties of cell-surface proteoglycans (HSPG) from the apical pole of HEC-1A accounted for at least 60% of both R5- and X4-HIV-1 attachment, showing their important implication in viral attachment. HEC-1A cells also have the capacity to endocytose a weak proportion of the attached virus and pass it along to underlying cells. Fucose, N-acetylglucosamine and mannosylated-residues inhibited the transcytosis of some virus isolates, suggesting that mannose receptors can be implicated on the both R5- and X4-HIV-1 transcytosis. The inhibition of HIV transcytosis by blocking CCR5 mAb suggests the implication of specific interaction between the viral gp120 and sulfated moiety of syndecans during the transcytosis of mostly R5- and X4-HIV-1. At the basolateral pole of HEC-1A, HSPG sequestered X4- and not R5-HIV-1, highlighting the important role of HEC-1A as an X4 virus reservoir. The cell-free virus particles that have transcytosed could infect activated T cells but with a weaker efficiency than virus that had not transcytosed. The specific stimulation of HEC-1A by R5-HIV-1 increased the release of monocytes/chemokines-attracting chemokines (IL-8 and GR0) and proinflammatory cytokines (TNF-beta and IL-1alpha) that enhanced the production of virus by activated T cells. This study suggests that R5 and X4 viruses can differentially use epithelial cells to ensure their own spread.

HIV coreceptor and chemokine ligand gene expression in the male urethra and female cervix

OBJECTIVE

Isolates with a tropism for the coreceptor CCR5 are the predominant viral strain transmitted following heterosexual transmission. We have investigated coreceptor expression levels within male and female genital epithelia to assess whether selective transmission can be explained by elevated CCR5 expression within the genital epithelia per se.

DESIGN

Individuals attending a local genitourinary medicine unit were recruited, and samples of genital epithelia obtained using either a cytobrush (females) or urethral swab (males). Expression of coreceptor and cell marker mRNAs was then determined by reverse transcription (RT)-PCR.

METHODS

RNA was recovered from the epithelial cell samples then used as templates in competitive quantitative RT-PCR to measure mRNA expression of key chemokines, coreceptors and cell-type markers in the epithelial cell samples. Cell-surface coreceptor expression was also assessed in a sample of patients using fluorescent cell staining.

RESULTS

CXCR4 and CCR3 coreceptors were expressed at significantly higher levels than CCR5 within the female endo- and ectocervix and distal end of the male urethra. Increased levels of cell surface expressed CXCR4 compared to CCR5 was confirmed in samples obtained from the female genital tract by FACS analysis.

CONCLUSIONS

The selective transmission of CCR5-tropic viral variants is unlikely to result simply from differential coreceptor abundance at the genital epithelia.

Immunological microenvironments in the human vagina and cervix: mediators of cellular immunity are concentrated in the cervical transformation zone

Cell-mediated immunity (CMI) is key to defense against intracellular pathogens such as Chlamydia trachomatis and viruses that infect the lower female genital tract, but little is known about CMI at this site. Recent studies indicate that there are immunological microenvironments within the female genital tract, and that immune functions are affected by hormones as well as infections and inflammatory processes. To determine the distribution of mediators of CMI within the lower female genital tract, we have enumerated and characterized T-lymphocyte subsets and natural killer and antigen presenting cells (APCs; macrophages and dendritic cells) in the introitus, vagina, ectocervix, endocervix and cervical transformation zone (TZ) from healthy women, and have examined the effects of the menstrual cycle, menopause and inflammation on these parameters. In women without inflammation, T cells and APCs were most prevalent in the cervical TZ and surrounding tissue. Intraepithelial lymphocytes were predominantly CD8+ T cell+; most CD8+ cells in the TZ and endocervix, and a proportion of cells in the ectocervix, expressed T-cell internal antigen-1, a marker of cytotoxic potential. In contrast, the normal vaginal mucosa contained few T cells and APCs. Cervicitis and vaginitis cases had increased numbers of intraepithelial CD8+ and CD4+ lymphocytes and APCs. The menstrual cycle and menopause had no apparent effect on cellular localization or abundance in any of the lower genital tract tissues. These data indicate that the cervix, especially the TZ, is the major inductive and effector site for CMI in the lower female genital tract. Because CD4+ T cells and APCs are primary host cells for human immunodeficiency virus type 1 (HIV-1), these data also provide further evidence that the cervix is a primary infection site of HIV-1, and that inflammation increases the risk of HIV transmission.

Lipopolysaccharide-binding protein is produced in the epididymis and associated with spermatozoa and prostasomes

Lipopolysaccharide-binding protein (LBP) is an acute phase protein known to play a central role in the defense against Gram-negative bacteria. It binds lipopolysaccharides of Gram-negative bacteria and, after binding to CD14, the complex signals through Toll-like receptor (TLR)-4, eliciting host-defense responses, such as cytokine production, in inflammatory cells. The present study demonstrates constitutive expression of the gene encoding lipopolysaccharide-binding protein in the epithelium of the human epididymis by in situ hybridization. Using immunohistochemistry lipopolysaccharide-binding protein was shown to be present in the same cells and also attached to the heads and tails of spermatozoa. Cell-free seminal plasma, lysed spermatozoa and lysed prostasomes were subjected to Western blot; all showed immunoreactive bands corresponding to the size of lipopolysaccharide-binding protein. Gel filtration demonstrated that lipopolysaccharide-binding protein colocalizes with prostasomes. The concentration of lipopolysacharide-binding protein in seminal plasma was 127+/-42ng/mL (mean+/-S.D.; range 73-215ng/mL). Taken together, our results suggest roles for lipopolysaccharide-binding protein during human reproduction.

Ex vivo analysis of HIV-1 co-receptors at the endocervical mucosa of women using oral contraceptives

Combined oral contraceptives may alter the microenvironment of the female genital tract and, thus, influence susceptibility of endocervical cells to HIV-1 transmission. The mechanism for this effect is unknown but might involve combined oral contraceptive up-regulation of chemokine receptors on CD4+ endocervical cells. We measured chemokine co-receptor (CCR5 and CXCR4) expression on cervical intraepithelial CD4+ T lymphocytes, macrophages and dendritic cells using flow cytometry in 32 healthy women, 16 of whom were combined oral contraceptive users and 16 non-users. All women tested negative for sexually transmitted infections. Combined oral contraceptive users showed a higher proportion of CCR5+ CD4+ T lymphocytes compared with combined oral contraceptive non-users (P < 0.05). However, expression of both co-receptors on cervical intraepithelial macrophages and dendritic cells was no different between the two groups. Up-regulation of CCR5 on cervical intraepithelial CD4+ T lymphocytes offers a potential explanation by which women receiving combined oral contraceptives may be at increased risk of HIV transmission.