Herpes simplex virus-1 evasion of CD1d antigen presentation pathway

描述（由申请人提供）：疱疹病毒感染是一个重大的公共卫生问题。单纯疱疹病毒-1 （HSV-1）作为a-疱疹病毒科的模型病毒，是感染性致盲和脑炎的主要病原体。为了建立感染和逃避免疫系统的关键成分，在宿主细胞中保持潜伏，病毒进化出了复杂的免疫逃避策略。cd1受限的先天样NKT细胞对不同的病原体（包括病毒、细菌、真菌和寄生虫）具有重要的抗微生物功能。然而，包括病毒在内的病原体如何在感染和潜伏期间逃避NKT细胞的有效抗微生物功能尚不清楚。本建议的重点是HSV-1如何调节抗原呈递细胞中人类CD1d的表达以抑制NKT细胞的功能。我们最初发现，感染后，HSV-1迅速抑制细胞表面CD1d的表达，抑制NKT细胞的活化及其免疫调节功能。最近，我们发现两个病毒因子，糖蛋白B （gB）和蛋白激酶US3，是下调CD1d表面表达的最佳条件。特别是，gB靶向CD1d分子并将其重定位到TGN，而US3阻断CD1d的再循环，促进更多由gB介导的CD1d重定位到TGN。值得注意的是，这种免疫逃避机制只针对人类，而不是小鼠，这表明它是病毒与人类宿主共同进化的结果。为了剖析这种免疫逃避机制在体内的作用，我们成功地产生了人类CD1d敲入小鼠。我们提出三个相互关联的具体目标。首先，我们将描述gB-CD1d相互作用的分子细节，并绘制这些蛋白质中的相互作用结构域。其次，我们将研究病毒蛋白US3与gB协同下调CD1d的分子和细胞机制。最后，我们将利用我们的新小鼠模型研究gB和US3蛋白如何抑制NKT细胞功能。我们将具体研究CD1d的下调如何抑制NKT细胞的初始激活和募集到感染部位。进一步鉴定被evasins抑制的NKT细胞效应功能将为治疗和预防HSV-1感染提供新的线索或治疗手段。这一建议具有高度创新性，其成功的结果将成为一项重大发现，将显著影响我们对疱疹病毒介导的免疫逃避的理解，并可能为开发有效的疫苗和抗病毒药物提供手段。

DESCRIPTION (provided by applicant): Herpesvirus infection is a major public health problem. Herpes simplex virus-1 (HSV-1), as the model virus for a-herpesvirus family, is the leading pathogen for infection-caused blindness and encephalitis. To establish infection and escape critical components of the immune systems to remain latent in host cells, the virus has evolved sophisticated immune evasion strategies. CD1d-restricted innate-like NKT cells play critical anti-microbial functions against different pathogens, including viruses, bacteria, fungi, and parasites. However, it remains unclear how pathogens including viruses evade the potent anti-microbial functions of NKT cells during infection and latency. The specific emphasis of this proposal is how HSV-1 modulates human CD1d expression in antigen-presenting cells to inhibit NKT cell function. We have originally discovered that upon infection, HSV-1 rapidly suppresses CD1d expression on the cell surface and inhibits the activation of NKT cells and their immunoregulatory function. Recently, we have identified that two viral factors, glycoprotein B (gB) and protein kinase US3, are required for optimal downregulation of CD1d surface expression. In particular, gB targets and relocates CD1d molecules to the TGN, while US3 blocks CD1d recycling and facilitates more gB-mediated CD1d relocalization to the TGN. Remarkably, this immune evasion mechanism only targets human, but not mouse, CD1d suggesting it is a result of viral co- evolution with human host. To dissect the in vivo roles of tis immune evasion mechanism, we have successfully generated a human CD1d knock-in mouse. We propose three interrelated specific aims. First, we will delineate the molecular details of the gB-CD1d interaction and map the interaction domains in these proteins. Second, we will examine the molecular and cellular mechanism by which the viral protein US3 cooperates with gB to down-regulate CD1d. Finally, we will investigate how gB and US3 proteins inhibit NKT cell function using our new mouse model. We will specifically examine how the down-regulation of CD1d inhibits the initial activation and recruitment of NKT cells to the infection site. Further identification of the NKT cell effector function inhibited by the evasins will provide novel leads or therapeutic means to treat and prevent HSV-1 infection. This proposal is highly innovative and its successful outcome should serve as a major discovery that will significantly impact our understanding of herpesvirus-mediated immune evasion as well as potentially provide the means for developing effective vaccines and antiviral drugs.