GP130 Signaling During Chronic Virus Infection

描述(申请人提供)：多个抑制分子创造了一种深刻的免疫抑制环境，这种环境在慢性病毒感染中是保守的，并使诱导有效的免疫具有挑战性。与人类健康高度相关的人类持久性病毒，包括HIV、丙型肝炎病毒和乙肝病毒，仅限于人类和非人类灵长类动物，这给基于实验的研究带来了很大的限制和困难。免疫系统的复杂性不能在体外准确地重建，它的研究需要使用适当的整体有机体。因此，我们选择使用慢性淋巴细胞性脉络膜脑膜炎病毒(LCMV)感染其自然宿主小鼠作为模型系统。在先前的研究中，我们发现白细胞介素6(IL-6)在持续LCMV感染期间以一种独特的双相方式产生，而晚期IL-6促进T滤泡辅助反应，对病毒控制至关重要(Harker等人)。科学2011年)。IL6与IL6细胞因子家族共享转导共受体gp130，其中四种与免疫系统有关。我们的初步研究表明，在慢性LCMV感染期间，去除T细胞中的gp130会导致比单独缺乏IL6信号更严重的缺陷，这表现为病毒特异性的CD4T细胞数量减少及其IL-21分泌(此外)导致Tfh反应减弱。这些数据表明，gp130信号细胞因子，包括但不限于IL6，在协调CD4T细胞反应和解决体内持续的LCMV感染方面发挥着核心作用。我们建议研究在慢性LCMV感染过程中gp130信号细胞因子(除IL-6外)的作用及其与CD4T细胞反应的机制联系。在第一个目标中，我们将研究gp130 FLOX/FLOX小鼠，以探讨gp130信号在不同时间和特定细胞群中在慢性LCMV感染过程中的作用。我们将通过测量混合骨髓嵌合体中的存活和增殖来确定gp130控制CD4T细胞数量的机制。在目标2中，我们将探索CD4T细胞对gp130细胞因子(不包括IL6)的水平和反应性，并将使用shRNA和/或转基因小鼠来研究它们在慢性LCMV感染过程中的功能。在过去的三十年中，利用LCMV感染小鼠的研究表明，在小鼠和人类中，针对持续病毒的免疫反应高度保守。因此，从拟议的实验中获得的知识不仅将增强我们对基础免疫学的理解，还将指出在人类慢性病毒感染过程中可能调节免疫反应和代表治疗靶点的重要角色。此外，由于LCMV被认为是一种典型的ArenaVirus，建议的研究将增加我们对导致致命出血热的人类ArenaVirus发病机制的理解。

DESCRIPTION (provided by applicant): Multiple inhibitory molecules create a profoundly immunuosuppressive environment that is conserved among chronic viral infections and makes eliciting effective immunity challenging. Human persistent viruses highly relevant to health, including HIV, HCV and HBV are restricted to human and non- human primates, which poses great limitations and difficulties to experimental based research. The complexity of the immune system cannot be accurately recreated in vitro and its study requires the use of appropriate whole organisms. We have therefore chosen to use chronic lymphocytic choriomeningitis virus (LCMV) infection of its natural host, the mouse, as a model system. In a previous study, we found that interleukin-6 (IL- 6) is produced in a unique biphasic manner during persistent LCMV infection and that late IL-6 escalates T follicular helper responses, being essential for viral control (Harker et al. Science 2011). IL6 shares the transducing co-receptor gp130 with the IL6 family of cytokines of which four have been related to the immune system. Our preliminary studies indicate that ablation of gp130 in T cells during chronic LCMV infection resulted in more profound defects than the sole absence of IL6 signaling, as indicated by reduction of virus-specific CD4 T cell numbers and their IL-21 secretion (in addition) to diminished Tfh responses. These data indicate that gp130 signaling cytokines, including but not limited to IL6, play a central role in orchestrating CD4 T cells responses and resolving persistent LCMV infection in vivo. We propose to investigate the role of gp130 signaling cytokines (other than IL-6) and their mechanistic link to CD4 T cell responses during chronic LCMV infection. In Aim #1 we will study gp130flox/flox mice to investigate the role of gp130 signaling at different times and in specific cell populations during chronic LCMV infection. We will determine the mechanism underlying gp130 control of CD4 T cell numbers by measuring survival and proliferation in mixed bone marrow chimeras. In Aim 2 we will explore the levels of and CD4 T cell responsiveness to gp130-cytokines (other than IL6) and we will use shRNA and/or genetically modified mice to investigate their function during chronic LCMV infection. Studies in the past three decades using LCMV murine infection have demonstrated high conservation in the immune responses against persistent viruses in mouse and humans. Therefore the knowledge gained from the proposed experiments will not only enhance our understanding of basic immunology but also point out important players that could regulate immune responses and represent therapeutic targets during chronic viral infections in humans. Furthermore, since LCMV is considered a prototypic arenavirus the proposed studies will increase our understanding of the pathogenesis of human arenaviruses, which cause fatal hemorrhagic fevers.