Blockade of T-cell Co-Inhibitory Pathways & Immunotherapy to Prevent Ocular Herpe

描述（由申请人提供）：在美国，单纯疱疹病毒1型（HSV-1）是感染性病原体导致角膜失明的最常见原因。大多数眼部疱疹疾病是由于潜伏感染的三叉神经节（TG）神经元的病毒再激活，而不是原发性急性感染。预防再激活需要病毒、神经元和免疫系统之间复杂的相互作用。虽然宿主的CD 8 + T细胞在控制潜伏感染的TG神经元的HSV-1再活化中起着关键作用，但该病毒已经进化出免疫逃避策略作为反击，以保护自身免受宿主的CD 8 + T细胞的攻击。我们最近在潜伏感染的TG中发现了功能失调的HSV特异性CD 8 + T细胞，这增强了对潜伏期HSV-1免疫逃避机制的理解。这是由HSV-1潜伏相关转录物（LAT）引发的，LAT是潜伏感染期间大量转录的唯一病毒基因。基于强有力的已发表和初步数据，本申请集中于：（1）理解在潜伏感染的TG中导致功能障碍的CD 8 + T细胞的LAT介导的机制;和（2）使用该知识来设计新的基于T细胞的强大免疫策略，以预防再激活、复发性眼病和失明。我们最近发现：（i）与LAT（-）病毒相比，在来自LAT（+）潜伏感染的小鼠的TG中，三种T细胞共抑制受体PD- 1、TIM-3和BTLA在HSV特异性CD 8 + T细胞上高度表达，但在HSV特异性CD 4 + T细胞上不表达。(ii)LAT（+）TG中相当比例的HSV特异性CD 8 + T细胞部分功能失调。(iii)与LAT（-）TG相比，LAT（+）TG中PD-L1和HVEM表达增加。这些有趣的结果，结合其他相关领域的报道，我们推测：（1）在HSV-1潜伏感染的TG中，LAT通过一种或多种T细胞抑制途径促进CD 8 + T细胞功能障碍并损害其免疫监视功能，从而促进病毒从潜伏感染的神经元中重新激活;（2）逆转CD 8 + T细胞的功能障碍将减少HSV-1的再活化、复发性眼病，并防止视力丧失。我们的具体目标是：目标1：确定T细胞共抑制受体PD-1、TIM-3和BTLA在“人源化”HLA Tg小鼠的TG驻留CD 8 + T细胞上的表达动力学，所述小鼠眼部感染HSV-1 LAT（+）与HSV-1 LAT（-），并确认这些共抑制途径在潜伏感染的TG中观察到的CD 8 + T细胞功能障碍中的作用。目标二：检验以下假设：体内阻断PD-1/PD-L1、TIM-3/GAL-9和/或BTLA/HVEM T细胞抑制性信号传导途径将恢复CD 8 + T细胞保护功能并增强“人源化”HLA Tg小鼠中治疗性免疫的功效。这项转化研究，聚集了一个多学科的团队，解决了目前NEI大胆的目标倡议：“通过小分子方法治疗眼病和恢复视力的新疗法的开发。“在‘人源化’HLA Tg小鼠中成功完成这项临床前研究，应该会导致一种新的和强大的免疫疗法，以防止致盲复发性疱疹疾病。

DESCRIPTION (provided by applicant): In the United States, herpes simplex virus type 1 (HSV-1) is the most common cause of corneal blindness due to an infectious agent. Most ocular herpes disease is due to viral reactivations from latently infected neurons of the trigeminal ganglia (TG), rather than to primary acute infection. Prevention of reactivations requires a complex interplay between the virus, the neurons, and the immune system. While the host's CD8+ T cells play a critical role in controlling HSV-1 reactivation from latently infected neurons of TG, the virus has evolved immune evasion strategies as a counter-defense to protect itself from being attacked by the host's CD8+ T cells. Understanding the mechanisms of HSV-1 immune evasion during latency has been enhanced by our recent discovery of dysfunctional HSV-specific CD8+ T cells in latently infected TG. This is triggered by the HSV-1 Latency Associated Transcript (LAT), the only viral gene abundantly transcribed during latent infection. Building on strong published and preliminary data, this application focuses on: (1) Understanding the LAT- mediated mechanisms that lead to dysfunctional CD8+ T cells in latently infected TG; and (2) Using that knowledge to devise novel powerful T-cell based immunotherapeutic strategies to prevent reactivations, recurrent eye disease and blindness. We have recently found that: (i) Three T-cell co-inhibitory receptors, PD- 1, TIM-3, and BTLA are highly expressed on HSV-specific CD8+ T cells, but not on HSV-specific CD4+ T cells, in TG from mice latently infected with LAT(+) compared to LAT(-) virus. (ii) A significant proportion of HSV- specific CD8+ T cells in LAT(+) TG are partially dysfunctional. (iii) PD-L1 and HVEM expression are increased in LAT(+) TG compared to LAT(-) TG. These intriguing results, together with related reports by others in the field, lead us to hypothesize that: (1) In HSV-1 latently infected TG, LAT promotes dysfunction of CD8+ T-cells and impairs their immuno-surveillance function through one or several T-cell inhibitory pathways, thus promoting virus reactivation from latently infected neurons; and (2) Reversing the dysfunction of CD8+ T-cells will decrease HSV-1 reactivation, recurrent eye disease, and prevent loss of sight. Our specific Aims are: Aim 1: Determine the kinetics of expression of T-cell co-inhibitory receptors, PD-1, TIM-3, and BTLA, on TG-resident CD8+ T cells of "humanized" HLA Tg mice ocularly infected with HSV-1 LAT(+) vs. HSV-1 LAT(-) and confirm the role of these co-inhibitory pathways in the dysfunction of CD8+ T-cells seen in latently infected TG. Aim 2: Test the hypothesis that in vivo blocking of PD-1/PD-L1, TIM-3/GAL-9 and/or BTLA/HVEM T-cell inhibitory signaling pathways will restore CD8+ T cell protective function and enhance the efficacy of therapeutic immunization in "humanized" HLA Tg mice. This translational research, that gathers a multidisciplinary team, addresses the current NEI Audacious Goals Initiative: "Development of new treatments through small molecules approach to treat eye disease and to restore sight." Successful completion of this pre-clinical study in "humanized" HLA Tg mice should lead to a novel and powerful immunotherapy to prevent blinding recurrent herpetic disease.