Interferon Effects on HIV Transmission in Human Models

描述(申请人提供)：艾滋病病毒的性传播效率相对较低。大多数性接触不会导致传播。在精液中成群的病毒中，通常只有一个病毒粒子被传播。在SIV传播给雌性猕猴的过程中，感染在生殖器组织的一小部分CD4T细胞中传播，这是目前艾滋病毒传播给女性的模型的基础。在第一周，SIV仅限于生殖器粘膜，在那里病毒在系统性传播之前放大，从而提供了一个干预措施可以抑制传播的机会之窗。这项提案将探索两个“人类”模型--极化的人类宫颈移植组织和移植了胎儿人类造血干细胞、肝脏和胸腺的人源化小鼠(“BLT小鼠”)中的艾滋病毒传播。我们的第一个目标是研究正常宫颈组织中浸润性造血细胞的细胞类型、表型和组织分布，并将其与BLT模型中的人类细胞分布进行比较。这将提供有关BLT小鼠生殖器粘膜与人类相似程度的重要信息。第二个目标是确定宫颈组织培养物和经阴道感染的BLT小鼠中艾滋病毒感染的特征，以确定第一批感染细胞，并了解感染如何在组织中放大和传播。此外，我们还将描述在HIV感染后两种模型中免疫细胞激活和细胞因子、干扰素和趋化因子诱导的变化。这些变化被认为是为了提高粘膜中常驻细胞对艾滋病毒的易感性，并促进更多易感细胞的招募。HIV感染巨噬细胞和T细胞不会触发胞内天然免疫核酸感受器诱导I型干扰素。这些传感器对艾滋病毒的逃避是由TREX1 DNA酶介导的，该酶消化失败的逆转录本。树突状细胞缺乏有效的艾滋病毒复制 细胞也能有效地抑制大多数树突状细胞亚群产生的干扰素。在慢性HIV感染中，I型干扰素的主要来源是浆细胞样树突状细胞，通常在未发炎的生殖器粘膜中找不到。我们对AIM 3的基本假设是，缺乏即刻的干扰素反应使艾滋病毒能够在组织中站稳脚跟。我们假设，在生殖道的CD4+细胞中敲除TREX1将在受感染的T细胞中触发对HIV的干扰素反应，从而抑制局部病毒复制的爆发。然而，早期诱导干扰素也可能会增强炎症和免疫细胞向生殖器粘膜的募集，这可能会产生相反的效果。因此，需要进行体内研究来破译干扰素在传播点的影响。在目标3中，干扰素水平将通过使用外源性干扰素？治疗、下调TREX1和其他涉及干扰素表达的基因以及中和干扰素活性的抗体来控制在阴道内暴露HIV的时间。我们将重点分析局部I型干扰素诱导对HIV复制的影响、生殖器粘膜中CD4T细胞的激活状态、免疫细胞向组织的招募以及调节免疫细胞进出组织的细胞因子、趋化因子和趋化因子受体的表达。

DESCRIPTION (provided by applicant): Sexual transmission of HIV is relatively inefficient. Most sexual exposures do not lead to transmission. Of the swarms of virus in the semen, only a single virion is usually transmitted. In SIV transmission to female macaques, which is the basis for current models of HIV transmission to women, infection propagates in a small focus of genital tissue CD4 T cells. In the first week, SIV is restricted to the genital mucosa where the virus amplifies before systemic dissemination, providing a window of opportunity where intervention could inhibit transmission. This proposal will explore HIV transmission in 2 "human" models - polarized human cervical explants and humanized mice transplanted with fetal human hematopoietic stem cells, liver and thymus ("BLT mice"). Our first aim is to characterize the cell types, phenotype and tissue distribution of infiltrating hematopoietic cells in normal human cervix and compare it with the distribution of human cells in the BLT model. This will provide important information about how closely the genital mucosa of BLT mice resembles humans. The second aim is to characterize HIV infection in cervical explant cultures and in BLT mice infected intravaginally to identify the first infected cells and understand how the infection amplifies and spreads in the tissue. In addition we will characterize the changes in immune cell activation and induction of cytokines, interferons and chemokines that occur in both models following HIV infection. These changes are hypothesized to enhance HIV susceptibility of resident cells in the mucosa and promote recruitment of additional susceptible cells. HIV infection of macrophages and T cells does not trigger cytosolic innate immune nucleic acid sensors to induce Type I interferons. HIV evasion of these sensors is mediated by the Trex1 DNase, which digests failed reverse transcripts. The lack of efficient HIV replication in dendritic cells also effectively suppresses interferon production by most dendritic cell subsets. The main source of Type I interferons in chronic HIV infection, plasmacytoid dendritic cells, are not normally found in the uninflamed genital mucosa. Our underlying hypothesis for aim 3 is that the lack of an immediate interferon response allows HIV to gain a foothold in the tissue. We hypothesize that knocking down TREX1 in CD4+ cells in the genital tract will trigger an IFN response to HIV in infected T cells that will suppress the local burst of viral replication. Howeve, early IFN induction might also enhance inflammation and recruitment of immune cells to the genital mucosa that could have an opposite effect. Therefore in vivo studies are needed to decipher the effect of interferons at the point of transmission. In aim 3, interferon levels will b manipulated around the time of intravaginal HIV exposure by treatment with exogenous interferon?, knockdown of TREX1 and other genes involved in interferon expression, and antibodies that neutralize interferon activity. We will focus on analyzing the effect of local TypeI interferon induction on HIV replication, the activation status of CD4 T cells in the genital mucosa, the recruitment of immune cells to the tissue and the expression of cytokines and chemokines and chemokine receptors that regulate immune cell ingress and egress from the tissue.