A novel APOBEC-based vaccine approach for HIV

项目摘要 HIV-1的巨大序列多样性仍然是开发有效的抗HIV-1抗体的主要障碍。 预防性疫苗人APOBEC 3G和3F蛋白是Vif缺陷型HIV-1的有效抑制剂。HIV-1 Vif通过诱导APOBEC 3G和3F的泛素化和随后的降解来抵消APOBEC 3G和3F。 蛋白酶体APOBEC蛋白酶体加工的增加可能导致APOBEC衍生的 HIV-1感染细胞表面的肽表位。因为高水平的APOBEC抗原可能是 因此，APOBEC表位存在于HIV感染细胞的表面，可以作为替代标记物 HIV-1感染。基于增加的APOBEC表位将CD 8 + T细胞靶向HIV-1感染的细胞 表达可以绕过HIV-1序列多样性的障碍。我们已经生成了初步数据 这表明HIV-1感染的精英控制者对来自HIV-1的表位产生了强烈的T细胞反应。 APOBEC 3G序列。我们还发现，精英控制的SIV感染猕猴 APOBEC特异性T细胞应答。基于这些初步观察，我们假设慢病毒 感染产生APOBEC特异性CD 8 + T细胞，其能够识别和消除病毒感染。 被感染的细胞此外，使用APOBEC序列的疫苗免疫原可以产生APOBEC特异性T细胞， 细胞，它可以识别并杀死感染任何HIV-1变体的细胞。这种新方法的目标是 感染的细胞基于它们呈递APOBEC衍生肽，而不是HIV-1肽。中心目标 我们的R21的目的是了解APOBEC表位特异性应答对总细胞免疫应答的贡献。 针对HIV-1和SIV的反应。这些研究将决定我们是否进入R33阶段， 计划我们对R33有两个目标。我们想知道APOBEC特异性CD 8 + T细胞是否会产生 在逆转录病毒感染过程中可以识别并消除病毒感染的细胞。此外，我们希望 确定疫苗诱导的APOBEC特异性细胞免疫应答是否可以控制病毒感染， SIV感染后的复制。我们假设，对Vif敏感的APOBEC蛋白特异的T细胞将 在体外和体内均抑制病毒复制。该项目将提供原理证明数据， APOBEC特异性T细胞特异性抑制SIV/HIV-1的复制。因此，这些研究是第一个 迈向一种新的疫苗方法，通过以下方式绕过HIV-1序列多样性的障碍： 针对HIV感染的替代标记。

PROJECT SUMMARY The enormous sequence diversity of HIV-1 remains a major obstacle to the development of an effective prophylactic vaccine. Human APOBEC3G and 3F proteins are potent inhibitors of Vif-deficient HIV-1. HIV-1 Vif counteracts APOBEC 3G and 3F by inducing their ubiquitination and subsequent degradation by the proteasome. Increased proteasomal processing of APOBEC could lead to presentation of APOBEC-derived peptide epitopes on the surface of HIV-1-infected cells. Because higher levels of APOBEC antigens might be present on the surface of HIV-infected cells, APOBEC epitopes could, therefore, serve as a surrogate marker of HIV-1 infection. Targeting CD8+ T cells to HIV-1-infected cells based on increased APOBEC epitope expression could circumvent the obstacle of HIV-1 sequence diversity. We have generated preliminary data that shows HIV-1 infected elite controllers mount strong T cell responses to epitopes derived from the APOBEC3G sequence. We have also discovered that elite-controlling SIV-infected macaques mount APOBEC specific T cell responses. Based upon these initial observations, we hypothesize that lentiviral infection generates APOBEC-specific CD8+ T cells, which are capable of recognizing and eliminating virally infected cells. Further, a vaccine immunogen using APOBEC sequences could generate APOBEC specific T cells, which could recognize and kill a cell infected with any variant of HIV-1. This novel approach targets infected cells based on their presentation of APOBEC derived peptides, not HIV-1 peptides. The central goal of our R21 is to understand the contribution of APOBEC epitope-specific responses to the total cellular immune response directed at HIV-1 and SIV. These studies will dictate whether we proceed to the R33 stage of the plan. We have two goals for the R33. We want to know whether APOBEC-specific CD8+ T cells arising during retroviral infections can recognize and eliminate virally infected cells. Additionally, we want to determine whether vaccine-induced APOBEC-specific cellular immune responses might provide control of viral replication after SIV infection. We hypothesize that T cells specific for Vif-sensitive APOBEC proteins will suppress viral replication both in vitro and in vivo. This project would provide proof-of-principle data that APOBEC-specific T cells specifically suppress replication of SIV/HIV-1. These studies are, therefore, the first steps towards a novel vaccine approach, which circumvents the obstacle of HIV-1 sequence diversity by targeting a surrogate marker of HIV infection.