Plasma Oxylipins Levels in Nonalcoholic Fatty Liver Disease.

BACKGROUND: Activation of innate immunity by gut-derived immunogens such as lipopolysaccharides (LPS) may play an important role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Whether NAFLD-associated lipid disturbances and polyunsaturated fatty acid (PUFA) metabolism in particular contribute to heightened innate immunity, remains to be determined. OBJECTIVE: To determine if oxylipins, metabolic products of PUFA metabolism, enhance innate immune reactivity alone and/or following exposure to LPS. METHODS: Plasma and peripheral blood mononuclear cells (PBMC) were collected from 35 NAFLD patients and 8 healthy controls. Oxylipin levels were documented by HPLC-MS/MS, cytokines (IL-1, IL-6, IL-10, and TNF-α) by ELISA, and chemokine receptors (CCR1 and CCR2) by flow cytometry. RESULTS: Mean plasma levels of four pro-inflammatory oxylipins (Tetranor 12-HETE, 20-HETE, 8-HETrE, and 7-HDoHE) were significantly elevated in NAFLD patients compared to healthy controls. However, the levels did not correlate with the severity of liver injury as reflected by serum aminotransferases, ck18M30, and Fib-4 determinations. In vitro, 20-HETE (0.01-100 nM), the plasma oxylipin with the most significantly elevated plasma levels, did not alter NAFLD or control PBMC cytokine release or enhance the increases in cytokine release following 24 h of LPS exposure. Similarly, 20-HETE alone did not alter PBMC CCR1 or CCR2 expression or LPS-induced downregulation of these receptors. CONCLUSIONS: Pro-inflammatory oxylipin levels are increased in NAFLD, but these metabolites do not appear to drive short-term direct or LPS-induced increases in PBMC cytokine release or chemotaxis.

Human Immunodeficiency Virus-Infected Women Have High Numbers of CD103-CD8+ T Cells Residing Close to the Basal Membrane of the Ectocervical Epithelium.

Background: Genital mucosa is the main portal of entry for various incoming pathogens, including human immunodeficiency virus (HIV), hence it is an important site for host immune defenses. Tissue-resident memory T (TRM) cells defend tissue barriers against infections and are characterized by expression of CD103 and CD69. In this study, we describe the composition of CD8+ TRM cells in the ectocervix of healthy and HIV-infected women. Methods: Study samples were collected from healthy Swedish and Kenyan HIV-infected and uninfected women. Customized computerized image-based in situ analysis was developed to assess the ectocervical biopsies. Genital mucosa and blood samples were assessed by flow cytometry. Results: Although the ectocervical epithelium of healthy women was populated with bona fide CD8+ TRM cells (CD103+CD69+), women infected with HIV displayed a high frequency of CD103-CD8+ cells residing close to their epithelial basal membrane. Accumulation of CD103-CD8+ cells was associated with chemokine expression in the ectocervix and HIV viral load. CD103+CD8+ and CD103-CD8+ T cells expressed cytotoxic effector molecules in the ectocervical epithelium of healthy and HIV-infected women. In addition, women infected with HIV had decreased frequencies of circulating CD103+CD8+ T cells. Conclusions: Our data provide insight into the distribution of CD8+ TRM cells in human genital mucosa, a critically important location for immune defense against pathogens, including HIV.

Molecular Signatures of Immune Activation and Epithelial Barrier Remodeling Are Enhanced during the Luteal Phase of the Menstrual Cycle: Implications for HIV Susceptibility.

UNLABELLED: The variable infectivity and transmissibility of HIV/SHIV has been recently associated with the menstrual cycle, with particular susceptibility observed during the luteal phase in nonhuman primate models and ex vivo human explant cultures, but the mechanism is poorly understood. Here, we performed an unbiased, mass spectrometry-based proteomic analysis to better understand the mucosal immunological processes underpinning this observed susceptibility to HIV infection. Cervicovaginal lavage samples (n = 19) were collected, characterized as follicular or luteal phase using days since last menstrual period, and analyzed by tandem mass spectrometry. Biological insights from these data were gained using a spectrum of computational methods, including hierarchical clustering, pathway analysis, gene set enrichment analysis, and partial least-squares discriminant analysis with LASSO feature selection. Of the 384 proteins identified, 43 were differentially abundant between phases (P < 0.05, ≥2-fold change). Cell-cell adhesion proteins and antiproteases were reduced, and leukocyte recruitment (interleukin-8 pathway, P = 1.41E-5) and extravasation proteins (P = 5.62E-4) were elevated during the luteal phase. LASSO/PLSDA identified a minimal profile of 18 proteins that best distinguished the luteal phase. This profile included cytoskeletal elements and proteases known to be involved in cellular movement. Gene set enrichment analysis associated CD4(+) T cell and neutrophil gene set signatures with the luteal phase (P < 0.05). Taken together, our findings indicate a strong association between proteins involved in tissue remodeling and leukocyte infiltration with the luteal phase, which may represent potential hormone-associated mechanisms of increased susceptibility to HIV. IMPORTANCE: Recent studies have discovered an enhanced susceptibility to HIV infection during the progesterone-dominant luteal phase of the menstrual cycle. However, the mechanism responsible for this enhanced susceptibility has not yet been determined. Understanding the source of this vulnerability will be important for designing efficacious HIV prevention technologies for women. Furthermore, these findings may also be extrapolated to better understand the impact of exogenous hormone application, such as the use of hormonal contraceptives, on HIV acquisition risk. Hormonal contraceptives are the most widely used contraceptive method in sub-Saharan Africa, the most HIV-burdened area of the world. For this reason, research conducted to better understand how hormones impact host immunity and susceptibility factors important for HIV infection is a global health priority.

Presence of CD8+ T cells in the ectocervical mucosa correlates with genital viral shedding in HIV-infected women despite a low prevalence of HIV RNA-expressing cells in the tissue.

The female genital tract is a portal of entry for sexual HIV transmission and a possible viral reservoir. In this study, the ectocervical CD8+ T cell distribution was explored in situ and was related to expression of CD3 and HLA-DR and presence of HIV RNA. For this purpose, ectocervical tissue samples and genital secretions were collected from HIV-seropositive (HIV+) Kenyan female sex workers (FSWs) (n = 20), HIV-seronegative (HIV-) FSWs (n = 17), and HIV(-) lower-risk women (n = 21). Cell markers were assessed by in situ staining and by quantitative PCR. HIV RNA expression in tissue was analyzed by in situ hybridization, and viral shedding was assessed by quantitative PCR. The HIV+ FSW group had a higher amount of total cells and CD8+, CD3+, and HLA-DR+ cells compared with the HIV(-)FSW group and HIV- lower-risk women. The majority of CD8+ cells were CD3+ T cells, and the numbers of CD8+ cells correlated significantly with plasma and cervical viral load. HIV RNA expression in situ was found in 4 of the 20 HIV+FSW women but did not correlate with cervical or plasma viral load. Thus, the HIV+ women displayed high numbers of CD8+, CD3+, and HLA-DR+ cells, as well as a limited number of HIV RNA+ cells, in their ectocervical mucosa; hence, this localization cannot be neglected as a potential viral reservoir. The elevated levels of CD8+ T cells may play a role in the immunopathogenesis of HIV in the female genital tract.

Stable CD4 expression and local immune activation in the ectocervical mucosa of HIV-infected women.

Studies using genital tissue samples from HIV-infected women might provide important information about HIV susceptibility and transmission. In this study, ectocervical biopsies were obtained from 20 HIV-seropositive (HIV(+)) Kenyan female sex workers (FSW) and 20 HIV-seronegative lower risk (HIV(-) LR) women. To control for the impact of sex work, 20 HIV(-) FSW were also recruited. Immune molecules were assessed in situ by immunohistochemistry and for mRNA expression by quantitative PCR. The HIV(+) women were reportedly infected for a median of 3 y (1-21 y), with a median viral load of 11,735 copies/ml (20-648,000 copies/ml). These women had significantly lower CD4 blood cell counts than the HIV(-) LR women but comparable levels of CD4 expression in ectocervix. Whereas cellular markers were similar between the HIV(+) group and the HIV(-) LR women, the HIV-binding molecules CCR5, dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin, and mannose receptor as well as the inflammatory markers CD69, IFN-γ, IL-6, and IL-22 were significantly upregulated in the HIV(+) group. As compared with the HIV(-) FSW women, the HIV(+) women had significantly upregulated levels of CD4, CD3, CCR5, Langerin, dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin, and mannose receptor as well as inflammatory cytokines. The CD4 cell depletion previously seen in the gut mucosa of HIV-infected individuals was thus not observed in the ectocervical mucosa. Stable CD4 cell expression and local immune activation in the lower female genital tract may promote viral replication and genital shedding and increase the risk of sexual HIV transmission.

High pH reversed-phase chromatography as a superior fractionation scheme compared to off-gel isoelectric focusing for complex proteome analysis.

MS/MS is the technology of choice for analyzing complex protein mixtures. However, due to the intrinsic complexity and dynamic range present in higher eukaryotic proteomes, prefractionation is an important step to maximize the number of proteins identified. Off-gel IEF (OG-IEF) and high pH RP (Hp-RP) column chromatography have both been successfully utilized as a first-dimension peptide separation technique in shotgun proteomic experiments. Here, a direct comparison of the two methodologies was performed on ex vivo peripheral blood mononuclear cell lysate. In 12-fraction replicate analysis, Hp-RP resulted in more peptides and proteins identified than OG-IEF fractionation. Distributions of peptide pIs and hydropathy did not reveal any appreciable bias in either technique. Resolution, defined here as the ability to limit a specific peptide to one particular fraction, was significantly better for Hp-RP. This leads to a more uniform distribution of total and unique peptides for Hp-RP across all fractions collected. These results suggest that fractionation by Hp-RP over OG-IEF is the better choice for typical complex proteome analysis.

Human interferon regulatory factor-1 gene and its promoter sequences revealed by population-based complete gene sequencing.

Interferon regulatory factor-1 (IRF-1) plays important roles in host immunity, cell proliferation and apoptosis. The current GenBank sequence for human IRF-1 (accession number: L05072) was derived from a human placenta DNA library and reported in 1992. In one recent population-based sequence study, we observed consistent discrepancies between our IRF-1 sequence data and GenBank reference sequences suggesting that, current IRF-1 reference sequence was not representative for all populations. By complete gene sequencing, we obtained a representative full-length IRF-1 sequence from a single subject. Compared to submission L05072, our population-based data contains: 35 nucleotide additions, 8 nucleotide removals and another 12 nucleotide replacements. A single nucleotide difference was observed in the IRF-1 promoter sequence compared to GenBank sequence (X53095). These changes were confirmed in 350 Kenyans and 28 non-African donors. The accuracy of a reference sequence is crucial for downstream genetic and functional studies and this study provides more complete and accurate data on the sequence of the human IRF-1 gene and its immediate promoter region.

QASI: A collaboration for implementation of an independent quality assessment programme in India.

OBJECTIVE: The HIV pandemic remains a significant global health concern. Accurate determination of CD4+ T-cells in patient samples relies on reliable CD4 enumeration. The Quality Assessment and Standardization programme for Immunological measures relevant to HIV/AIDS (QASI) programme of the Public Health Agency of Canada provides clinical laboratories from resource-limited countries with a mechanism to evaluate the quality of CD4 testing and develop the implementation of an independent national External Quality Assessment (EQA) programme. This study describes how QASI helped develop the capacity for managing a sustainable national CD4 EQA programme in India. DESIGN: Supported by the Public Health Agency of Canada and Clinton Foundation HIV/AIDS Initiative, QASI engaged with the National AIDS Control Organization and the Indian National AIDS Research Institute to assist in technology transfer in preparation for the implementation/management of an independent CD4 EQA programme. Technology transfer training was provided to support corrective actions and to improve the quality of CD4 testing. Inter-laboratory variation of EQA surveys between pre- and post-skill development was compared. RESULTS: Prior to training, coefficient of variation values were 14.7% (mid-level CD4 count controls) and 39.0% (low-level). Following training, variation was reduced to 10.3% for mid-level controls and 20.0% for low-level controls. CONCLUSION: This training assisted the National AIDS Control Organization and the Indian National AIDS Research Institute in identifying the information necessary for management of an EQA programme, and developed the foundation for India to provide corrective actions for sites with challenges in achieving reliable results for CD4 enumeration. This led to a demonstrable improvement in CD4 testing quality and illustrates how country-specific training significantly improved CD4 enumeration performance for better clinical management of HIV care in India.

Quality assurance for HIV point-of-care testing and treatment monitoring assays.

In 2015, UNAIDS launched the 90-90-90 targets aimed at increasing the number of people infected with HIV to become aware of their status, access antiretroviral therapies and ultimately be virally suppressed. To achieve these goals, countries may need to scale up point-of-care (POC) testing in addition to strengthening central laboratory services. While decentralising testing increases patient access to diagnostics, it presents many challenges with regard to training and assuring the quality of tests and testing. To ensure synergies, the London School of Hygiene & Tropical Medicine held a series of consultations with countries with an interest in quality assurance and their implementing partners, and agreed on an external quality assessment (EQA) programme to ensure reliable results so that the results lead to the best possible care for HIV patients. As a result of the consultations, EQA International was established, bringing together EQA providers and implementers to develop a strategic plan for countries to establish national POC EQA programmes and to estimate the cost of setting up and maintaining the programme. With the dramatic increase in the number of proficiency testing panels required for thousands of POC testing sites across Africa, it is important to facilitate technology transfer from global EQA providers to a network of regional EQA centres in Africa for regional proficiency testing panel production. EQA International will continue to identify robust and cost-effective EQA technologies for quality POC testing, integrating novel technologies to support sustainable country-owned EQA programmes in Africa.

Non-Cationic Proteins Are Associated with HIV Neutralizing Activity in Genital Secretions of Female Sex Workers.

OBJECTIVE: Cationic proteins found in cervicovaginal secretions (CVS) are known to contribute to the early antiviral immune response against HIV-infection in vitro. We here aimed to define additional antiviral factors that are over-expressed in CVS from female sex workers at high risk of infection. METHODS: CVS were collected from Kenyan HIV-seronegative (n = 34) and HIV-seropositive (n = 12) female sex workers, and were compared with those from HIV-seronegative low-risk women (n = 12). The highly exposed seronegative (HESN) sex workers were further divided into those with less (n = 22) or more (n = 12) than three years of documented sex work. Cationic protein-depleted CVS were assessed for HIV-neutralizing activity by a PBMC-based HIV-neutralizing assay, and then characterized by proteomics. RESULTS: HIV neutralizing activity was detected in all unprocessed CVS, however only CVS from the female sex worker groups maintained its HIV neutralizing activity after cationic protein-depletion. Differentially abundant proteins were identified in the cationic protein-depleted secretions including 26, 42, and 11 in the HESN>3 yr, HESN<3 yr, and HIV-positive groups, respectively. Gene ontology placed these proteins into functional categories including proteolysis, oxidation-reduction, and epidermal development. The proteins identified in this study include proteins previously associated with the HESN phenotype in other cohorts as well as novel proteins not yet associated with anti-HIV activities. CONCLUSION: While cationic proteins appear to contribute to the majority of the intrinsic HIV neutralizing activity in the CVS of low-risk women, a broader range of non-cationic proteins were associated with HIV neutralizing activity in HESN and HIV-positive female sex workers. These results indicate that novel protein factors found in CVS of women with high-risk sexual practices may have inherent antiviral activity, or are involved in other aspects of anti-HIV host defense, and warrant further exploration into their mode of action.

Mucosal serpin A1 and A3 levels in HIV highly exposed sero-negative women are affected by the menstrual cycle and hormonal contraceptives but are independent of epidemiological confounders.

OBJECTIVE: Serpins (serine protease inhibitors) are associated with protection against HIV infection. Here, we characterized mucosal serpin expression in the genital tract of HIV highly exposed sero-negative (HESN) women meeting our epidemiological definition of HIV resistance in relation to epidemiological variables. METHODS: Cervicovaginal lavage (CVL) fluid and plasma were collected from 84 HIV-resistant, 54 HIV-uninfected, and 66 HIV-infected female commercial sex workers. Serpin A1 and A3 concentrations were measured by ELISA and compared with clinical information. RESULTS: Mucosal serpin A1 was elevated during proliferative phase over secretory phase (P = 0.017*), while A3 remained similar (P = 0.25). Plasma and mucosal serpin A1/A3 levels were not associated with each other and appeared compartment specific (r = 0.21, r = 0.056). Serpin A1/A3 expression did not associate with age (r = 0.009, r = -0.06), duration of sex work (r = 0.13, r = -0.10), clients per day (r = -0.11, r = -0.02), concurrent STIs (P = 0.36, P = 0.15), but was lower in women using hormonal contraceptives (P = 0.034, P = 0.008). Mucosal serpin A1/A3 levels in HIV-infected individuals were not significantly different with disease status as determined by plasma CD4(+) T-cell counts (P = 0.94, P = 0.30). CONCLUSION: This study shows the relationship of serpins to the menstrual cycle and hormonal contraceptives, as well as their independence to epidemiological sexual confounders. This information provides a broader understanding of innate components of the mucosal immune system in women.

Human rElafin Inhibits HIV-1 Replication in Its Natural Target Cells.

Trappin-2/elafin is a novel innate immune factor that belongs to the serine protease inhibitor family and has known antibacterial, antifungal, and antiviral properties. In this study, we further investigated the anti-HIV activity of elafin using different cellular models and both X4- and R5-HIV-1 laboratory strains. We compared the antiviral activity of human recombinant elafin (rElafin) with three well-known antiretroviral drugs, AZT, tenofovir, and enfuvirtide. We have found that when the virus is pre-incubated with rElafin prior to the infection of the cells, HIV-1 replication is significantly inhibited. In target T cells and human peripheral blood mononuclear cells, maximal inhibition was achieved using submicromolar concentrations, and rElafin was found to be as potent as enfuvirtide, showing its potential for therapeutic application. We also show data on the mechanism of the antiviral activity of rElafin. We have demonstrated that rElafin neither binds to CD4, CXCR4, or CCR5 host cell receptors, nor to the viral glycoproteins gp120 and gp41. Furthermore, in our cell-to-cell fusion assays, in contrast to enfuvirtide, rElafin failed to block cell fusion. Altogether our results indicate that rElafin interferes with HIV replication at the early steps of its cycle but with a different mechanism of action than enfuvirtide. This study provides the first experimental evidence that elafin inhibits HIV replication in its natural target cells; therefore, elafin might have potential for its development as a new anti-HIV drug or microbicide.

Feasibility and safety of cervical biopsy sampling for mucosal immune studies in female sex workers from Nairobi, Kenya.

BACKGROUND: There is an urgent need to improve our understanding of the mucosal immuno-pathogenesis of HIV acquisition in the female genital tract, particularly in high-risk women such as female sex workers (FSWs). Cervical biopsy samples offer technical advantages over cytobrush sampling, but there are concerns that this might increase HIV acquisition, particularly if healing is slow and/or women do not abstain from sex during healing. METHODOLOGY/PRINCIPAL FINDINGS: Cervical biopsy samples and cervico-vaginal swabs for co-infection diagnostics, prostate specific antigen (PSA) and immune studies were collected from 59 women, including HIV seropositive and HIV-exposed seronegative (HESN) FSWs as well as lower risk women from Nairobi, Kenya. A clinical-demographic questionnaire was administered and women were instructed to avoid sexual intercourse, douching and the insertion of tampons for 14 days. All participants underwent a repeat exam to assess healing within the 14 days, and had HIV diagnostics at six months. Cervical sampling was well tolerated, and 82% of participants had healed macroscopically by 5 days. Both self-report and PSA screening suggested high levels of compliance with pre- and post-procedure abstinence. Delayed healing was associated with vulvovaginal candidiasis (VVC) and HESN status. At six-month follow up all low-risk and HESN participants remained HIV seronegative. CONCLUSION: Cervical biopsy sampling is a safe and well-tolerated method to obtain cervical biopsies in this context, particularly if participants with VVC are excluded. As healing could be delayed up to 11 days, it is important to support (both financially and with rigorous counseling) a period of post-procedure abstinence to minimize HIV risk.

A TRIM5alpha exon 2 polymorphism is associated with protection from HIV-1 infection in the Pumwani sex worker cohort.

OBJECTIVE: The innate immune component TRIM5alpha has the ability to restrict retrovirus infection in a species-specific manner. TRIM5alpha of some primate species restricts infection by HIV-1, whereas human TRIM5alpha lacks this specificity. Previous studies have suggested that certain polymorphisms in human TRIM5alpha may enhance or impair the proteins affinity for HIV-1. This study investigates the role of TRIM5alpha polymorphisms in resistance/susceptibility to HIV-1 within the Pumwani sex worker cohort in Nairobi, Kenya. A group of women within this cohort remain HIV-1-seronegative and PCR-negative despite repeated exposure to HIV-1 through active sex work. DESIGN: A 1 kb fragment of the TRIM5alpha gene, including exon 2, from 1032 women enrolled in the Pumwani sex worker cohort was amplified and sequenced. Single-nucleotide polymorphisms (SNPs) and haplotypes were compared between HIV-1-positive and resistant women. METHODS: The TRIM5alpha exon 2 genomic fragment was amplified, sequenced and genotyped. Pypop32-0.6.0 was used to determine SNP and haplotype frequencies and statistical analysis was carried out using SPSS-13.0 for Windows. RESULTS: A TRIM5alpha SNP (rs10838525) resulting in the amino acid change from arginine to glutamine at codon 136, was enriched in HIV-1-resistant individuals [P = 1.104E-05; odds ratio (OR) 2.991; 95% confidence interval (CI) 1.806-4.953] and women with 136Q were less likely to seroconvert (P = 0.002; log-rank 12.799). Wild-type TRIM5alpha exon 2 was associated with susceptibility to HIV-1 (P = 0.006; OR 0.279; 95% CI 0.105-0.740) and rapid seroconversion (P = 0.001; log-rank 14.475). CONCLUSIONS: Our findings suggest that a shift from arginine to glutamine at codon 136 in the coiled-coil region of TRIM5alpha confers protection against HIV-1 in the Pumwani sex worker cohort.

Multiple T-cell epitopes overlap positively-selected residues in the p1 spacer protein of HIV-1 gag.

OBJECTIVES: The p1 region of HIV-1 gag contains the frameshift stem-loop, gag-pol transframe and a protease cleavage site that are crucial for viral assembly, replication and infectivity. Identifying and characterizing CD8+ epitopes that are under host immune selection in this region will help in designing effective vaccines for HIV-1. DESIGN: An approach combining bioinformatical analysis and interferon gamma enzyme-linked immunosorbent spot (ELISPOT) assays is used to identify and characterize the epitopes. Potential human leukocyte antigen (HLA)-restricted epitopes were identified by correlating the positively-selected mutations with host HLA alleles. METHODS: ELISPOT analysis with overlapping peptides was used to confirm and characterize the epitopes. RESULTS: Four positively-selected residues were significantly associated with HLA class I alleles, including HLA B*1302 (K4R, P = 0.0008 and I5L, P = 0.0108), A*7401 (S9N, P = 0.0002) and A*30 genotypes (P7S, P = 0.009), suggesting epitopes restricted by these alleles are present in this region. ELISPOT analysis with patient peripheral blood mononuclear cells (PBMCs) identified seven novel epitopes restricted by the 3 alleles. Two types of epitopes were observed in this region based on the ELISPOT responses, Type I: the positively-selected variation does not affect CD8+ T-cell responses; and Type II: the CD8+ T-cell responses are determined by the epitope variants. CONCLUSION: We identified and characterized seven novel CD8+ epitopes in the p1 spacer protein region. Classifying the effects of positively-selected variants on CD8+ T-cell responses will help in designing effective vaccines for HIV-1.

Elevated elafin/trappin-2 in the female genital tract is associated with protection against HIV acquisition.

OBJECTIVES: Globally, heterosexual intercourse is the primary route of HIV-1 (HIV) transmission. It follows that mechanisms that protect against HIV infection are likely operative at the genital mucosa. In HIV-resistant Kenyan sex workers who are highly exposed to HIV infection yet remain uninfected, protection correlates with HIV-specific immune responses and genetic factors. However, these factors do not entirely explain this model of natural immunity to HIV. We hypothesized that protection may be mediated by innate immune proteins in the genital tract of HIV-resistant sex workers. DESIGN AND METHODS: The genital proteome of mucosal secretions from HIV-resistant women was examined using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. Cervical lavage samples were collected from 315 HIV-resistant, HIV-uninfected and HIV-infected commercial sex workers. RESULTS: Univariate analysis identified a 6 kDa biomarker of HIV resistance in genital secretions from these women. This protein was identified by tandem mass spectrometry as elafin and was found to be overexpressed in HIV-resistant women compared with HIV-uninfected (P = 0.001) and infected (P = 0.002) women. The elevated levels of elafin/trappin-2 in HIV-resistant women were confirmed using ELISA. The prospective association of elevated cervicovaginal elafin/trappin-2 levels with protection from HIV acquisition was then confirmed in an independent cohort of high-risk female sex workers. CONCLUSION: Using a unique proteomics approach in a large scale, cross-sectional cohort study, we identified elafin/trappin-2 as a novel innate immune factor, which is highly associated with resistance. This association was confirmed within an independent, prospective cohort study. Genital tract elafin/trappin-2 levels constitute a natural correlate of HIV protection in humans.

Identification of differentially expressed proteins in the cervical mucosa of HIV-1-resistant sex workers.

Novel tools are necessary to understand mechanisms of altered susceptibility to HIV-1 infection in women of the Pumwani Sex Worker cohort, Kenya. In this cohort, more than 140 of the 2000 participants have been characterized to be relatively resistant to HIV-1 infection. Given that sexual transmission of HIV-1 occurs through mucosal surfaces such as that in the cervicovaginal environment, our hypothesis is that innate immune factors in the genital tract may play a role in HIV-1 infection resistance. Understanding this mechanism may help develop microbicides and/or vaccines against HIV-1. A quantitative proteomics technique (2D-DIGE: two-dimensional difference in-gel electrophoresis) was used to examine cervical mucosa of HIV-1 resistant women ( n = 10) for biomarkers of HIV-1 resistance. Over 15 proteins were found to be differentially expressed between HIV-1-resistant women and control groups ( n = 29), some which show a greater than 8-fold change. HIV-1-resistant women overexpressed several antiproteases, including those from the serpin B family, and also cystatin A, a known anti-HIV-1 factor. Immunoblotting for a selection of the identified proteins confirmed the DIGE volume differences. Validation of these results on a larger sample of individuals will provide further evidence these biomarkers are associated with HIV-1 resistance and could help aid in the development of effective microbicides against HIV-1.

Elevated T cell counts and RANTES expression in the genital mucosa of HIV-1-resistant Kenyan commercial sex workers.

The initial site of exposure to human immunodeficiency virus (HIV)-1 during heterosexual transmission occurs in the genital tract. Although the majority of immunological studies have focused on the immune response to HIV-1 at the systemic level, our understanding of tissue-specific immunity is deficient. The goal of the present study was to characterize T cell populations found in the cervix of women shown to be resistant to infection by HIV-1. Levels of both systemic and cervical mucosal lymphocytes were compared between HIV-1-resistant, HIV-1-uninfected, and HIV-1-infected commercial sex workers (CSWs) as well as HIV-1-uninfected non-CSW control subjects at low risk for exposure. The HIV-1-resistant CSWs had increased cervical CD4+ and CD8+ T cell counts, compared with the HIV-1-uninfected CSWs; importantly, these increases were not reflected in the systemic lymphocyte compartment. There was a 2-fold increase in CD4+ T cell counts in the HIV-1-resistant CSWs, compared with both the HIV-1-infected and the HIV-1-uninfected CSWs. Expression of the HIV-1 coreceptors CCR5 and CXCR4 was also determined, and cytokine and beta chemokine levels in the genital mucosa were assessed. The HIV-1-resistant CSWs had a 10-fold increase in RANTES expression, compared with the HIV-1-uninfected CSWs. This is the first study to show elevated levels of beta chemokines and CD4+ T cells in the genital tracts of women who are exposed to HIV-1 and yet are uninfected.