High Cervical IFNε in Female Sex Workers. Homo sapiens

Highly Exposed-Seronegatives (HESN) individuals do not contract HIV-1 infection despite long-term exposure; few comprehensive studies examining behavior, mucosal tissue, and peripheral immune parameters in sexually-exposed HESN have been completed. To this end, we assessed rate of condomless vaginal sex, the immune activation status (peripheral blood) and gene expression (ectocervical biopsies) in female cohort of high-risk female sex workers [FSW] (n=50) and non-sex worker women [CG] (n=32) in San Juan, Puerto Rico, USA. Of the 50 FSWs examined only 5 had detectable anti-HIV responses by either HIV gag-specific CD8+ T-Cell responses or mucosal anti-HIV envelope IgG/IgA. FSW had a uniform lower CD38 expression on circulating CD4+ or CD8+ T-Cells (both: p<0.0001:Wilcoxon Rank Sum). Cervical tissue from FSWs had greater levels of CD4+ T-Cell (p=0.040), CD123+ plasmacytoid Dendritic Cells (p=0.013) and CD68+ macrophage infiltrates (p=0.038). Cervical gene expression by RNA microarray indicated that FSW had a gene signature characterized by lower expression of genes associated with leukocyte homing and chemotaxis; partial interferon regulated gene signature; and lower gene expression of genes required for HIV infection such as CD4 and NUP153 indicating a lower mucosal immune activation state and reduced susceptibility to HIV-1 infection within mucosal tissue. Notably, Interferon (IFN)-ε expression was higher in FSW than CG women, as detected by RNA (microarray) and protein (IHC) expression in cervical epithelium. The observed levels of IFNε were associated with the reported frequency of unprotected intercourse. Finally, IFNε was induced by treatment of the ECT1 cell line with seminal fluid, suggesting that semen exposure may contribute to long-term protection. Decreased levels of immune activation and gene expression required for HIV infection along with semen-induced epithelial Interferon ε production within the reproductive tract of FSWs highlight distinct host intrinsic resistance mechanisms that may contribute to long-term HIV seronegative status in spite of high-risk condomless sex. Overall design: In total 23 ectocervical biopsy samples were analyzed. Fourteen (14) biopsy samples were from a population of HIV-1 High-Risk Female Sex Workers (FSW) operating in San Juan, PR, USA. As a control, nine (9) biopsy samples were taken from women attending a maternal health clinic at the University of Puerto Medical Campus.

高度暴露血清阴性（Highly Exposed-Seronegatives, HESN）个体即便长期暴露于HIV-1环境中也不会发生感染；目前针对经性接触暴露的HESN个体的行为、黏膜组织及外周免疫参数的系统性研究仍较为有限。为此，我们针对美国波多黎各圣胡安地区的高危女性性工作者（female sex workers, FSW）队列（n=50）及非性工作者女性对照组（control group, CG，n=32）展开研究，评估内容包括无保护阴道性交频率、外周血免疫激活状态，以及宫颈外活检组织的基因表达情况。
在50名受访女性性工作者中，仅5人可通过HIV gag特异性CD8+ T细胞应答或黏膜抗HIV包膜IgG/IgA检测到抗HIV应答。女性性工作者的循环CD4+或CD8+ T细胞表面CD38表达水平均显著降低（二者均：p<0.0001，Wilcoxon秩和检验）。女性性工作者的宫颈组织中，CD4+ T细胞（p=0.040）、CD123+浆细胞样树突状细胞（p=0.013）及CD68+巨噬细胞的浸润水平更高（p=0.038）。
通过RNA芯片（RNA microarray）开展的宫颈基因表达分析显示，女性性工作者的基因表达特征具有以下特点：与白细胞归巢及趋化作用相关的基因表达下调、存在部分干扰素调控基因特征，以及HIV感染所需基因（如CD4及NUP153）的表达水平降低，这提示其黏膜免疫激活状态更低，且黏膜组织对HIV-1感染的易感性有所下降。
值得注意的是，通过RNA芯片及宫颈上皮免疫组化（immunohistochemistry, IHC）检测发现，女性性工作者体内干扰素ε（Interferon-ε, IFN-ε）的表达水平高于对照组女性，且IFNε的表达水平与受试者报告的无保护性交频率呈相关性。进一步实验显示，用精液处理ECT1细胞系可诱导其表达IFNε，这提示精液暴露可能参与了长期保护作用的形成。
女性性工作者生殖道内免疫激活水平降低、HIV感染所需基因表达下调，以及精液诱导上皮细胞产生干扰素ε，这些发现凸显了独特的宿主内在抵抗机制——即便存在高危无保护性行为，该机制也可能帮助维持长期的HIV血清阴性状态。
研究整体设计：本研究共分析了23例外宫颈活检样本。其中14例样本取自美国波多黎各圣胡安地区的HIV-1高危女性性工作者；作为对照，9例样本取自波多黎各大学医学园区孕产妇健康门诊就诊的女性。