Interferon Effects on HIV Transmission in Human Models

描述（由申请人提供）：艾滋病病毒的性传播是相对低效的。大多数性接触不会导致传播。在精液中的病毒群中，通常只有一个病毒粒子被传播。SIV传播给雌性猕猴，这是目前HIV传播给女性模型的基础，感染在生殖器组织CD4 T细胞的一个小焦点中传播。在第一周，SIV仅限于生殖器粘膜，在那里病毒在全身传播之前扩增，提供了干预可以抑制传播的机会窗口。本课题将探索HIV在两种“人类”模型中的传播——极化人类宫颈外植体和移植了胚胎人类造血干细胞、肝脏和胸腺的人源化小鼠（“BLT小鼠”）。我们的第一个目的是表征正常人宫颈浸润性造血细胞的细胞类型、表型和组织分布，并将其与BLT模型中人细胞的分布进行比较。这将提供关于BLT小鼠生殖器粘膜与人类相似程度的重要信息。第二个目的是表征宫颈外植体培养和阴道内感染的BLT小鼠中的HIV感染，以确定第一批感染细胞，并了解感染如何在组织中扩增和扩散。此外，我们将描述免疫细胞激活和诱导细胞因子、干扰素和趋化因子的变化，这些变化发生在HIV感染后的两种模型中。据推测，这些变化增强了粘膜中驻留细胞的HIV易感性，并促进了其他易感细胞的募集。HIV感染巨噬细胞和T细胞不会触发胞质先天免疫核酸传感器诱导I型干扰素。HIV逃避这些传感器是由Trex1 dna酶介导的，Trex1 dna酶可以消化失败的逆转录物。树突缺乏有效的HIV复制

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.