Interferon Effects on HIV Transmission in Human Models

描述（由申请人提供）：艾滋病毒的性传播相对低效。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。在SIV向雌性猕猴的传播中，这是目前HIV向女性传播模型的基础，感染在生殖器组织CD 4 T细胞的小病灶中传播。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，提供了一个干预可以抑制传播的机会窗口。该提案将在两种“人类”模型中探索HIV传播-极化的人类宫颈外植体和移植有胎儿人类造血干细胞、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中浸润的造血细胞的细胞类型、表型和组织分布，并将其与BLT模型中人类细胞的分布进行比较。这将提供关于BLT小鼠的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物和阴道内感染的BLT小鼠中的HIV感染，以识别第一个感染的细胞，并了解感染如何在组织中放大和传播。此外，我们还将描述HIV感染后两种模型中免疫细胞活化和细胞因子、干扰素和趋化因子诱导的变化。假设这些变化增强了粘膜中驻留细胞的HIV易感性，并促进了额外易感细胞的募集。 巨噬细胞和T细胞的HIV感染不会触发胞质先天免疫核酸传感器诱导I型干扰素。这些传感器的HIV逃避是由Trex 1 DNA酶介导的，它能阻止失败的逆转录。树突状细胞中缺乏有效的HIV复制， 细胞还有效地抑制大多数树突细胞亚群的干扰素产生。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，在未发炎的生殖器粘膜中通常不存在。我们对目标3的基本假设是，缺乏立即的干扰素反应使艾滋病毒在组织中获得立足点。我们假设，在生殖道中敲低CD 4+细胞中的TREX 1将在感染的T细胞中触发对HIV的IFN应答，这将抑制病毒复制的局部爆发。然而，早期IFN诱导也可能增强炎症和免疫细胞向生殖器粘膜的募集，这可能产生相反的效果。因此，需要进行体内研究来解释干扰素在传播点的作用。在目标3中，通过外源性干扰素？治疗，将在阴道内HIV暴露前后控制干扰素水平B，干扰素表达中涉及的TREX 1和其它基因的敲低，以及中和干扰素活性的抗体。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CD 4 T细胞的活化状态，免疫细胞向组织的募集，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.