Project 2 - Michael Betts

大多数艾滋病毒感染者在抗逆转录病毒疗法(ART)中断数周内出现艾滋病毒反弹。 淋巴组织(LT)，由淋巴结、扁桃体、腺样体、脾白髓、淋巴集合体组成 外周组织等)是长期HIV病毒维持和随后复发的主要场所 水库。在我们目前的知识不断完善的同时，潜伏感染的卵泡助手(TFH)和 在接受抗逆转录病毒治疗的受试者中，LT内的中枢记忆(中医)CD4T细胞构成了主要的储存库。 重要的是，大多数T细胞不是静止的，可以离开并重新进入LT或其他外围部位。这 淋巴细胞在血液、外周组织和LT之间持续运动的过程，称为淋巴细胞 再循环，是免疫系统的中心过程。早期对淋巴细胞再循环的研究发现 一个淋巴细胞在血液中的平均时间只有60分钟，而足够多的淋巴细胞进入 从LT中取血，以取代所有血液中的血液，每天11倍。这种快速而大规模的迁移对 淋巴细胞对HIV免疫发病机制、根除和治疗的作用尚不清楚。在这里，我们将 测试(1)淋巴细胞再循环是否允许被感染的CD4T细胞播种和再分配 在慢性感染期间或ATI后，LT的避难所地点与其他外围水库地点之间，以及(2) 淋巴细胞再循环机制减少CD8T细胞与感染的CD4T细胞的潜在相互作用 LT内的单元格。我们将抑制经ART治疗的SIV感染恒河猴(RM)的淋巴细胞再循环 使用细胞迁移抑制剂FTY720[Fingolimod，一种鞘氨醇-1磷酸受体(S1PR)激动剂]。 FTY720抑制组织中T和B细胞的外流--尤其是LT。我们假设FTY720 在SIV感染的RM的ATI期间的治疗将防止重新激活的HIV感染的CD4T细胞离开LT和 在LT中保留新激活的SIV特异性CD8T细胞。因此，通过使用FTY720，我们将能够 在目标1中，确定抑制淋巴细胞再循环对急性心肌梗死后病毒动力学的影响 早期和晚期治疗SIV感染。使用条形码SIVmac239，我们将能够准确地描述 病毒反弹动力学、水库变化、复活率、水库多样化和同步性 在不同组织之间，并在仅无细胞的情况下在治疗中断后重新种植储存物， 而不是与细胞相关的，病毒可以中介这些效应。在目标2中，我们将确定CD8 T 细胞可限制早期和/或晚期治疗SIV的ATI后LT中病毒的重新激活和反弹 感染。在ART阻断后，FTY720将使CD8 T细胞停留在LT中。因此，我们可以 确定LT中的CD8 T细胞是否在功能上获得了控制或消除再次激活SIV感染的能力 治疗中断后的CD4T细胞。总而言之，这些研究将提供对源头的新见解 病毒反弹和控制病毒反弹的潜在策略。

HIV rebound occurs in most HIV infected individuals within weeks of antiretroviral therapy (ART) interruption. Lymphoid tissues (LT, composed of lymph nodes, tonsil, adenoid, splenic white pulp, lymphoid aggregates in peripheral tissues, etc.) are a major site for maintenance and subsequent recrudescence of the long-term HIV reservoir. While our current knowledge continues to be refined, latently infected follicular helper (Tfh) and central memory (Tcm) CD4+ T cells within LT make up the majority of the reservoir in ART treated subjects. Importantly, most T cells are not stationary, and can leave and re-enter LT or other peripheral sites. This process of continual movement of lymphocytes between blood, peripheral tissues, and LT, termed lymphocyte recirculation, is a central process of the immune system. Early studies of lymphocyte recirculation found that the average time a lymphocyte spends in blood is only ~ 60 minutes, and that enough lymphocytes enter the blood from LT to replace all those in blood 11x/day. The impact this rapid and massive migration of lymphocytes has for HIV immunopathogenesis, eradication, and cure remains unstudied. Here we will test whether (1) lymphocyte recirculation allows for the seeding and redistribution of infected CD4+ T cells between sanctuary sites in LT and other peripheral reservoir sites during chronic infection or after ATI, and (2) lymphocyte recirculation mechanisms reduce the potential interaction of CD8+ T cells with infected CD4+ T cells within LT. We will inhibit lymphocyte recirculation in ART-treated SIV-infected rhesus macaques (RM) using the cell migration inhibitor FTY720 [fingolimod, a sphingosine-1 phosphate receptor (S1PR) agonist]. FTY720 inhibits the egress of T and B cells from tissues- especially LT. We hypothesize that FTY720 treatment during ATI in SIV-infected RM will prevent reactivated HIV infected CD4+ T cells from leaving LT and retain newly activated SIV-specific CD8+ T cells in LT. Through the use of FTY720, we will therefore be able to, in Aim 1, define the impact of inhibiting lymphocyte recirculation on viral dynamics following ATI in early and late treated SIV infection. Using barcoded SIVmac239, we will be able to precisely characterize viral rebound kinetics, reservoir changes, reactivation rate, reservoir diversification and synchronization between different tissue, and re-seeding of the reservoir following treatment interruption when only cell-free, rather than cell-associated, virus could mediate these effects. In Aim 2 we will determine whether CD8+ T cells can limit viral reactivation and rebound in LT following ATI in early and/or late treated SIV infection. FTY720 will cause CD8+ T cells to remain in the LT following ART interruption. We can therefore determine whether CD8+ T cells in LT functionally gain the ability to control or eliminate reactivating SIV-infected CD4+ T cells after therapy interruption. Together these studies will provide new insight into the source of viral rebound and potential strategies to control viral rebound.