HIV-Human Peritonal Macrophage Interactions

描述(由申请人提供)：巨噬细胞是HIV病毒能够高效复制并保持潜伏状态的主要细胞类型之一，在HIV发病机制中发挥着关键作用。与CD4+T细胞相比，巨噬细胞对艾滋病毒诱导的杀伤具有抵抗力，并具有较长的寿命。事实上，巨噬细胞似乎是一个重要的储存库，在艾滋病患者和高致病性希氏病毒感染的恒河猴体内的CD4+T细胞耗尽后，巨噬细胞维持着高病毒载量。重要的是，巨噬细胞是机会性感染期间艾滋病毒的主要来源，这种感染在艾滋病晚期发生得更频繁。由于长期存活的艾滋病毒宿主构成了根除艾滋病毒的主要障碍，了解艾滋病毒-巨噬细胞相互作用的细胞和分子机制对于开发新的有效治疗艾滋病毒和艾滋病流行的策略至关重要。 原代巨噬细胞对HIV的敏感性取决于细胞的解剖位置和激活状态。由于难以分离大量人原代巨噬细胞，阻碍了HIV-1与巨噬细胞相互作用的实验研究。我们最近证实，腹膜巨噬细胞(PM)在肝硬变患者的腹水中高度丰富，并且对HIV-1感染易感。这些细胞在体外存活时间很长，可以超低温保存。新分离的PM对HIV R5、X4、X4R5初级分离株敏感，但对X4-T细胞系适应株(TCLA)不敏感。有趣的是，培养7天后，PM获得了对X4-TCLA菌株的敏感性，并产生了比新分离的PM更多的原代X4和X4R5 HIV。同时，CXCR4mRNA水平和CC趋化因子的产生在培养7d内显著增加，提示HIV辅助受体和CC趋化因子水平的增加可能分别与X4-TCLA的易感性和X4致病株的病毒产量增加有关。 当巨噬细胞是HIV的主要来源时，HIV辅助受体从R5到X4的转换与CD4+T细胞的快速丢失和艾滋病的进展有关。虽然HIV共受体切换的基础归因于病毒群体与免疫系统中各种细胞群体的复杂相互作用，但巨噬细胞对HIV共受体切换的贡献尚不清楚。我们的长期目标是确定巨噬细胞是否作为重要的储存库，以及它们是否在疾病进展的后期阶段在艾滋病毒-辅助受体开关中发挥作用。因此，对HIV-腹膜巨噬细胞相互作用的进一步表征将为了解巨噬细胞在HIV发病机制中的作用提供重要的见解。 这项建议的目的是剖析在PM中动态使用HIV共同受体的潜在机制，并从HIV感染者的腹膜巨噬细胞中扩增和鉴定HIV包膜。这项研究的结果将加深我们对巨噬细胞在HIV发病机制中作用的理解，并可能有助于发现新的治疗方法。 公共卫生相关性：这项建议的目标是剖析在PM中动态使用HIV共同受体的潜在机制，并描述HIV感染患者PM中的HIV Env的特征。

DESCRIPTION (provided by applicant): Macrophages, one of the major cell types in which HIV can both productively replicate and persist in a latent state, play a crucial role in HIV pathogenesis. In contrast to CD4+ T cells, macrophages are resistant to HIV-induced killing and have long lifespan. Indeed, macrophages appear to be an important reservoir and sustain high virus loads after depletion of CD4+ T cells in AIDS patients and in highly pathogenic SHIV- infected rhesus macaques. Importantly, macrophages are the major source of HIV during opportunistic infections, which occur more frequently during the advanced stages of AIDS. Because the long-lived HIV reservoirs constitute a major obstacle to HIV eradication, understanding the cellular and molecular mechanisms underlying HIV-macrophage interactions is vital for developing novel and efficacious therapeutic strategies against HIV and the AIDS epidemic. Susceptibility of primary macrophages to HIV depends on the anatomical location and activation state of the cells. Experimental investigation of the interactions between HIV-1 and macrophages has been impeded by the difficulty of isolating a large amount of human primary macrophages. We recently demonstrate that peritoneal macrophages (PMs) are highly abundant in ascitic fluid of patients with cirrhosis and are susceptible to HIV-1 infection. These cells are long-lived in vitro and can be cryopreserved. Freshly isolated PMs are susceptible to HIV R5, X4, X4R5 primary isolates by not but not to X4-T cell line adapted (TCLA) strains. Interestingly, after 7 days in culture, PMs acquired susceptibility to X4-TCLA strains and produced greater amounts of primary X4 and X4R5 HIV than freshly-isolated PMs. Concurrently, the level of CXCR4 mRNA and production of CC-chemokines increased significantly during 7 days in culture, suggesting that an increase in levels of HIV-coreceptors and CC-chemokines may contribute to the susceptibility to X4-TCLA and enhanced viral production of X4-ultizing isolates, respectively. HIV coreceptor switch from R5 to X4 has been associated with rapid CD4+ T cell loss and progression of AIDS when macrophages are the major source of HIV. Although the basis for HIV co-receptor switch is attributed to the complex interaction of the viral population with various cell populations of the immune system, the contribution by macrophages to HIV co-receptor switch is not known. Our long-term goal is to determine whether macrophages serve as an important reservoir and whether they play a role in HIV-coreceptor switch at the late stage of disease progression. Thus, further characterization of HIV-peritoneal macrophage interactions will offer an important insight into the role of macrophages in HIV pathogenesis. The goal of this proposal is to dissect the underlying mechanisms of dynamic HIV co-receptor usages in PMs and to amplify and characterize HIV envelopes from peritoneal macrophages from HIV-infected individuals. The outcome of this study will enhance our understanding of the role of macrophages in HIV pathogenesis and may facilitate discoveries of new ways for treatment. PUBLIC HEALTH RELEVANCE: The goal of this proposal is to dissect the underlying mechanisms of dynamic HIV co-receptor usages in PMs and to characterize HIV Env in PMs from HIV-infected patients.