Mechanisms Underlying Clearance of the Persistently Infected CNS

清除持续感染的中枢神经系统的潜在机制

• 批准号: 8149640
• 负责人: Dorian McGavern
• 金额: $ 129.83万
• 依托单位: NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8149640
• 关键词: Mechanisms; Underlying; Clearance; Persistently; Infected

Persistent viruses, such as human immunodeficiency virus (HIV), cause major health problems worldwide and are extraordinarily difficult to clear following the establishment of persistence. Given the challenges associated with clearing persistent infections, it is important to develop and mechanistically understand therapeutic strategies that successfully achieve viral eradication without inducing permanent damage to the host. We model states of persistent infection in our laboratory using lymphocytic choriomeningitis virus (LCMV), a mouse as well as human pathogen. Persistent LCMV infections can be established by infecting mice in utero or by infecting adult mice intravenously with specific strains of the virus. When mice are persistently infected at birth or in utero with LCMV, the virus establishes systemic persistence, infecting both peripheral tissues as well as the central nervous system (CNS). Adult LCMV carrier mice are centrally tolerant to the virus at the T cell level and thus unable to eradicate the pathogen. We model persistent infection in adult mice by infecting with more aggressive strains of LCMV such as clone 13. Infection with clone 13 initiates a state of persistence that shares some important features with HIV-1 infection in humans, including infection / impairment of dendritic cells, exhaustion / deletion of the virus-specific T cells, and rapid establishment of viral persistence in the CNS as well as peripheral tissues. Both of the aforementioned models of LCMV persistence enable us to study how the immune system can be manipulated or supplemented to control a persistent viral infection in the CNS and periphery. Over the past year, we have pursued research focused on two important areas pertaining to persistent viral infections: immunoregulatory mechanisms and adoptive immunotherapy. One of the most exciting areas of persistent viral infection research focuses on the identification and therapeutic neutralization of molecules that suppress immune function and facilitate persistence. We theorize that the regulatory network is particularly robust within the CNS because of the need to preserve non-replicative cells such as neurons. Recent studies in the LCMV clone 13 model system have shown that therapeutic blockade of regulatory pathways such as PD-1 / PD-L1 and IL-10 can improve T cell function and promote viral clearance. We recently observed that the PD-L1 pathway is heavily upregulated in the CNS during a persistent LCMV infection. However, the mechanism by which PD-L1 regulates T cell dynamics and function was unknown. Therefore, we set out to define mechanistically how this pathway functions to suppress T cell activity in the brain and secondary lymphoid tissues during persistent infection. Using two-photon microscopy (TPM), we imaged fluorescent protein tagged LCMV specific CD8 and CD4 T cells undergoing T cell exhaustion (or loss of function) during a persistent clone 13 infection. Interestingly, T cell exhaustion was associated with a dynamic lock down. Both anti-viral CD8 and CD4 T cells formed stable immunological synapses with target cells that lasted for hours. These stable interactions appeared to simultaneously impede both T cell mobility and function. To determine the importance of the PD-1 pathway on these interactions, we administered an antagonistic antibody and monitored anti-viral T cell dynamics by TPM. Following administration of anti-PD-1, anti-viral CD8 and CD4 T cells were immediately released from synaptic lock down and become highly motile. This coincided with increased effector function, immunopathology, and overt disease. These data indicate that PD-1 / PD-L1 pathway contributes to immune exhaustion by rendering anti-viral T cells immobile. We are in the process of further evaluating how this and other regulatory pathways protect the CNS from T cell mediated injury. The other area of focus in the laboratory is on the development and characterization of adoptive immunotherapies to treat persistent viral infections. Total body control of persistent infections can be attained both in mice and humans by adoptively transferring anti-viral immune cells (referred to as adoptive immunotherapy). Therapies have traditionally focused on administration of anti-viral T cells. However, we recently made the observation that anti-viral B cells to accelerate clearance of a persistent viral infection. We propose that particularly challenging viruses like HIV-1 require all three arms of the adaptive immune system to engage simultaneously before viral control can occur. In the LCMV clone 13 system, we have noted that eventual control of the virus in the CNS and periphery is associated with a late emerging anti-viral B cell response. To improve the efficiency of viral control, we have developed and treated mice with a B cell immunotherapy consisting of LCMV-specific B cells. Administration anti-viral B cells to mice with a persistent LCMV infection elevated circulating anti-LCMV antibodies and accelerated viral control by trapping pathogen in immune complexes. These data indicate that it is possible to harness anti-viral B cells for the benefit of controlling a persistent viral infection. We predict that usage B cells in conjugation with anti-viral T cells may improve our ability to purge difficult to treat pathogens like HIV-1. We are presently focused on optimizing our B cell immunotherapy and defining dynamics of failing versus successful anti-viral B cell responses by TPM.

持续性病毒，例如人类免疫缺陷病毒（HIV），在全球范围内引起重大健康问题，并且在建立持久性后难以清除。鉴于与清除持续感染相关的挑战，重要的是要开发和机械理解的治疗策略，这些策略成功地消除了病毒性，而不会诱导宿主永久损害。 我们使用淋巴细胞脉络膜宿主性炎病毒（LCMV），小鼠和人类病原体对实验室中持续感染的状态进行建模。 持续的LCMV感染可以通过在子宫内感染小鼠或通过特异性病毒菌株静脉内感染成年小鼠来建立。 当小鼠在出生时或用LCMV的子宫内持续感染时，该病毒会建立全身性持久性，感染外围组织以及中枢神经系统（CNS）。成年LCMV载体小鼠在T细胞水平上对病毒的中心耐受性，因此无法消除病原体。 We model persistent infection in adult mice by infecting with more aggressive strains of LCMV such as clone 13. Infection with clone 13 initiates a state of persistence that shares some important features with HIV-1 infection in humans, including infection / impairment of dendritic cells, exhaustion / deletion of the virus-specific T cells, and rapid establishment of viral persistence in the CNS as well as peripheral tissues. 上述LCMV持久性的两个模型使我们能够研究如何操纵或补充免疫系统，以控制中枢神经系统和外围的持续病毒感染。 在过去的一年中，我们进行了研究，重点是与持续病毒感染有关的两个重要领域：免疫调节机制和收养免疫疗法。 持续性病毒感染研究最令人兴奋的领域之一是鉴定和治疗性中和分子的治疗性中和，这些分子抑制免疫功能并促进持久性。 我们认为，由于需要保留非复制性细胞（如神经元），因此在中枢神经系统中调节网络特别健壮。 LCMV克隆13模型系统的最新研究表明，诸如PD-1 / PD-L1和IL-10等调节途径的治疗阻滞可以改善T细胞功能并促进病毒清除率。 我们最近观察到，在持续的LCMV感染期间，中枢神经系统中的PD-L1途径大大上调。 但是，PD-L1调节T细胞动力学和功能的机制尚不清楚。 因此，我们着手定义该途径在持续感染过程中如何抑制大脑和继发性淋巴组织中T细胞活性的作用。 使用两光子显微镜（TPM），我们成像荧光蛋白在持续的克隆13感染期间经历了T细胞耗尽（或功能丧失）的LCMV特异性CD8和CD4 T细胞。 有趣的是，T细胞耗尽与动态锁定有关。 抗病毒CD8和CD4 T细胞均与持续数小时的靶细胞形成稳定的免疫突触。 这些稳定的相互作用似乎同时阻碍了T细胞的迁移率和功能。 为了确定PD-1途径对这些相互作用的重要性，我们通过TPM进行了拮抗抗体并监测抗病毒T细胞动力学。 施用抗PD-1后，抗病毒CD8和CD4 T细胞立即从突触锁中释放并变得高度运动。 这与效应子功能，免疫病理学和明显疾病的增加相吻合。 这些数据表明，PD-1 / PD-L1途径通过使抗病毒T细胞固定而导致免疫疲劳。 我们正在进一步评估该中枢神经系统免受T细胞介导的损伤的影响。 实验室中的另一个重点领域是对收养免疫疗法的发展和表征，以治疗持续的病毒感染。通过过养的抗病毒免疫细胞（称为收养免疫疗法），可以在小鼠和人类中同时获得对持续感染的全部控制。 传统上，疗法专注于抗病毒T细胞的给药。 但是，我们最近观察到，抗病毒B细胞加速了持续病毒感染的清除。 我们建议，像HIV-1这样的特别具有挑战性的病毒要求自适应免疫系统的所有三个臂在发生病毒控制之前同时参与。 在LCMV克隆13系统中，我们注意到中枢神经系统和外围病毒的最终控制与晚期新兴的抗病毒B细胞反应有关。 为了提高病毒控制的效率，我们通过由LCMV特异性B细胞组成的B细胞免疫疗法开发和治疗了小鼠。 通过持续的LCMV感染给小鼠施用抗病毒B细胞，通过将病原体捕获在免疫复合物中，使循环抗LCMV抗体和加速病毒控制升高。 这些数据表明，可以利用抗病毒B细胞来控制持续的病毒感染。 我们预测，与抗病毒T细胞结合的使用B细胞可能会提高我们清除难以治疗病原体（如HIV-1）的能力。 目前，我们专注于优化B细胞免疫疗法，并定义失败与成功的抗病毒B细胞反应的动力学。