Activating Latently Infected Cells Using Specific Antigens Including Those of HIV-1

 描述（由申请人提供）：尽管治疗将病毒复制降低到几乎检测不到的水平，但HIV-1仍无法治愈，因为病毒库在宿主中持续存在。这些储库持续存在，因为病毒主要在CD 4阳性记忆T细胞中建立潜伏感染。这些细胞以低但相对恒定的频率重新激活，导致药物治疗停止后1-2周内复发的病毒血症。这些再激活事件可能是随机的，但我们假设它们可以由细胞编程响应的特定抗原诱导。在这里，我们建议测试这一假设，并定义这些抗原，朝着开发新的方法来重新激活潜伏感染的细胞，是有效的，但选择性的目标。在R21阶段，特异性目标1将确定是否可以通过HIV-1抗原刺激逆转感染患者细胞中的潜伏期。HIV感染有利于对病毒本身产生免疫反应的细胞，因此我们假设许多（如果不是大多数）潜伏感染的CD 4阳性记忆T细胞会对HIV抗原产生反应。为了验证这一点，我们将测量HIV感染者潜伏感染细胞中病毒基因表达的体外再激活，首先使用对应于HIV-1蛋白的肽库，其次使用复制缺陷但真实的完整病毒体，我们可以大量生产，作为抗原。通过比较HIV-1抗原的再激活与最大T细胞刺激的再激活，我们将确定特异性抗原刺激的有效性。特异性目标2将确定在感染的CD 4阳性T细胞中，潜伏期是否可以被患者可能具有免疫记忆的HIV-1以外的抗原逆转。具体目标3将比较这些抗原逆转潜伏期的能力与其刺激总体CD 4 T细胞群体的能力;这测试了潜伏期在具有不同抗原特异性的细胞中差异性建立的假设，特别是它优先在HIV特异性细胞中建立。从HIV或其他病原体中识别抗原，激活大量潜伏感染细胞 从患者离体获得的细胞是进展到R33期的里程碑。R33阶段将提供对上述测试的抗原用于治疗性“疫苗接种”的潜力的深入研究，以实现免疫学再活化和消除潜伏感染细胞的目标。具体目标4将通过优化抗原混合物并将其应用于更大的患者细胞群来确定该方法的广泛适用性。特异性目标5将决定被特异性抗原再活化的潜伏感染细胞是否自发死亡或可被先天性和获得性细胞毒性免疫的各个方面杀死。这些研究应该有助于临床试验的设计，其目标是通过提供细胞程序化应答的抗原来重新激活潜伏感染的细胞，并促进识别和杀死这些细胞的细胞毒性免疫。

 DESCRIPTION (provided by applicant): HIV-1 is not cured despite therapy that reduces viral replication to nearly undetectable levels, because reservoirs of virus persist in the host. These reservoirs persist because the virus establishes latent infection, primarily in CD4-positive memory T cells. These cells reactivate at a low but relatively constant frequency, leading to recrudescent viremia within 1-2 weeks after drug-therapy is stopped. These reactivation events are presumably stochastic, but we hypothesize that they can be induced by the specific antigens to which the cells are programmed to respond. Here, we propose to test this hypothesis and define those antigens, toward the goal of developing new approaches to the reactivation of latently infected cells that are potent yet selective. During the R21 phase, Specific Aim 1 will determine whether latency can be reversed in cells from infected patients by stimulation with HIV-1 antigens. HIV-infection favors cells that respond immunologically to the virus itself, so we hypothesize that many if not most latently infected CD4-positive memory T cells will respond to HIV antigens. To test this, we will measure the reactivation of viral gene expression ex vivo in latently infected cells from HIV-infected persons, first using peptide pools corresponding to HIV-1 proteins, and second, using replication-defective but authentic whole virions, which we can produce in large amounts, as antigens. By comparing the reactivation by HIV-1 antigens to that of maximal T cell stimulation, we will determine how effective specific antigenic stimulation might be. Specific Aim 2 will determine whether latency can be reversed in infected CD4-positive T cells by antigens other than HIV-1 to which the patient likely has immunologic memory. Specific Aim 3 will compare the abilities of these antigens to reverse latency with their abilities to stimulate the overall CD4 T cell population; this tests the hypotheis that latency is differentially established in cells with different antigen-specificities, and in particular that it is established preferentially in HIV-specific cells. The identification of antigns, either from HIV or other pathogens, that activate a substantial fraction of latently infected cells from patients ex vivo is the milestone for progression to the R33 phase. The R33 phase will provide in depth study of the potential of the antigens tested above to be used in therapeutic "vaccinations", toward the goal of immunologically reactivating and eliminating latently infected cells. Specific Aim 4 will determine the broad applicability of the approach by optimizing antigenic mixtures and applying them to a larger cohort of patient cells. Specific Aim 5 will determine whether latently infected cells reactivated by specific antigens die spontaneously or can be killed by various aspects of innate and acquired cytotoxic immunity. These studies should facilitate the design of clinical trials, the goal of which would be to reactivate latently infected cells by provision of antigens to which the cells are programmed to respond, and to promote cytotoxic immunity that recognizes and kills those cells.