Interactions Between HIV and SIV with DC-SIGN & DC-SIGNR

描述：（由申请人提供）HIV-1进入细胞需要 病毒Env蛋白、CD 4和辅助受体之间的相互作用。绑定时 有效的病毒感染需要CD 4，病毒附着到 细胞表面可以通过与各种分子的相互作用来介导， 其中一些已经被很好地表征。附着于细胞表面， SE可以是进入途径中的限制步骤。体外，细胞感染 细胞系和PBMC通过HIV-1的作用可以通过在细胞系和PBMC中包含聚阳离子来增强。 病毒接种物或通过将病毒接种到细胞表面上。感染 激活的T细胞也可以通过首先将HIV-1结合到树突状细胞来增强。 细胞（DC）。去除未结合的病毒后，加入活化的T细胞 导致病毒非常有效地传播到这些细胞目标。 最近，一种称为DC-SIGN的II型整合膜蛋白已被证明 介导HIV-1与DC的结合。DC-SIGN包含C类型（即 钙依赖性）凝集素结构域，其介导该过程。因为DC 从周围粘膜组织迁移到淋巴结， 艾滋病病毒利用树突状细胞作为载体，使病毒能够进入淋巴组织。 更一般地说，DC-SIGN的发现提高了其他可能性。 存在高度特异性的病毒附着因子。我们发现， DC-SIGNR与DC-SIGN具有77%的氨基酸同一性， 支持艾滋病毒结合和传播。DC-SIGNR在内皮细胞上表达 淋巴结，肝脏和胎盘中的细胞，而DC-SIGN表达于 DC和某些类型的巨噬细胞在体内。DC-SIGN和DC-SIGNR的能力 以高亲和力结合病毒，增强淋巴细胞感染， 在粘膜表面和胎盘细胞上的表达， 这使我们假设这些蛋白质促进病毒与 细胞，并且一旦结合，病毒体被修饰和/或保护，和 最终更有效地呈递给关键靶细胞， 在宿主中的传播和扩散。在这份提案中，我们将继续 四个具体目标，将探讨结构，功能和表达 DC-SIGN和DC-SIGNR模式。此外，我们将开发试剂， 将使我们能够测试DC-SIGN在病毒性传播中的作用 使用恒河猴模型。我们建议采取高度合作的方式 方法采用的技能和专业知识的Doms和Hoxie实验室，以及 与其他实验室合作， 通过追求四个具体目标快速有效地解决。

DESCRIPTION:(provided by applicant)The entry of HIV-1 into cells requires interactions between the viral Env protein, CD4 and a coreceptor. While binding to CD4 is required for efficient virus infection, attachment of virus to the cell surface can be mediated by interactions with a variety of molecules, only some of which have been well characterized. Attachment to the cell surface per se can be a limiting step in the entry pathway. In vitro, infection of cell lines and PBMC by HIV-1 can be enhanced by inclusion of polycations in the virus inoculum or by centrifuging virus onto the cell surface. Infection of activated T-cells can also be enhanced by first binding HIV-1 to dendritic cells (DCs). After removing unbound virus, addition of activated T cells results in very efficient transmission of virus to these cellular targets. Recently, a type lI integral membrane protein termed DC-SIGN has been shown to mediate binding of HIV-1 to DCs. DC-SIGN contains a C-type (i.e. calcium-dependent) lectin domain that mediates this process. Because DCs migrate from peripheral mucosal tissues to lymph nodes, it has been proposed that HIV uses DCs as carriers, allowing the virus to access lymphoid tissue. More generally, the discovery of DC-SIGN raises the possibility that other highly specific virus attachment factors exist. Indeed, we have found that DC-SIGNR, which shares 77 percent amino acid identity with DC-SIGN, also supports HIV binding and transmission. DC-SIGNR is expressed on endothelial cells in lymph nodes, liver, and the placenta, while DC-SIGN is expressed on DCs and some types of macrophages in vivo. The ability of DC-SIGN and DC-SIGNR to bind virus with high affinity, to augment lymphocyte infection, and their expression on cells in mucosal surfaces and the placenta where transmission occurs leads us to hypothesize that these proteins facilitate viral binding to cells, and that once bound, virions are modified and/or protected, and ultimately presented more efficiently to key target cells that initiate viral propagation and dissemination in the host. In this proposal, we will pursue four Specific Aims that will explore the structure, function, and expression patterns of DC- SIGN and DC-SIGNR. Furthermore, we will develop reagents that will enable us to test the role of DC-SIGN in sexual transmission of virus using the rhesus macaque model. We propose to take a highly collaborative approach employing the skills and expertise of the Doms and Hoxie labs, as well as collaborations with other laboratories so that these questions can be addressed quickly and efficiently through the pursuit of 4 Specific Aims.