Selection of inflationary and tissue-resident T cells during MCMV infection

描述(申请人提供)：巨细胞病毒(CMV)是一种普遍存在的疱疹病毒，可引起系统性、持续性感染。CMV很少在人类中引起严重疾病，因为系统的、终身的免疫监测使病毒处于受控状态。事实上，巨细胞病毒刺激人类循环中已知的最大T细胞群。随着时间的推移，这些T细胞在一种称为“记忆膨胀”的过程中积累，并通过从潜伏期关闭病毒重新激活来控制CMV。出于这些原因，CMV可能会成为对抗癌症和艾滋病毒等疾病的新疫苗的工具。然而，当病毒传播给孕妇时，CMV可能会在发育中的胎儿中导致毁灭性的疾病。因此，预防CMV传播的疫苗被医学研究所列为最优先事项。了解病毒脱落部位的免疫监测将是预防传播和CMV疾病的关键。最近的研究表明，体内可能面临病毒重新激活的部位建立了一种名为“驻留记忆”T细胞(TRM)的T细胞群体。事实上，TRM细胞可能有助于控制疱疹病毒的重新激活。然而，还没有关于CMV特异性TRM细胞的研究。使用天然的小鼠疱疹病毒，小鼠(M)CMV，我们的数据显示，许多MCMV特异性的TRM细胞在唾液和乳腺中发育，这两个位置是已知的HCMV和MCMV的分泌点。更广泛地说，唾液和乳腺是几种人类疱疹病毒传播的两个部位。TRM细胞的个体发育和功能尚不清楚，这一差距是至关重要的，因为这些T细胞处于最佳位置，可能对控制疱疹病毒的重新激活至关重要。此外，促进这种“第一反应”--位于病原体入侵部位的细胞--是CMV载体疫苗的主要优势。目的1：我们将确定MCMV特异性TRM细胞是否控制病毒潜伏期，以及诱导TRM形成的疫苗是否将限制病毒复制。目的2：重复抗原识别和局部细胞因子环境被认为是调节TRM发生的两个因素。关键是，感染传播缺陷的巨细胞病毒，不能扩散到唾液腺，增加了唾液腺巨细胞巨细胞病毒特异性TRM细胞的形成，这意味着病毒复制或T细胞重复的抗原识别阻碍了TRM的发展。我们将使用一系列重组病毒来区分这些可能性。目的3：我们的初步数据显示，循环中的记忆膨胀是由对病毒抗原的竞争推动的。成功竞争的T细胞会膨胀；而那些充满竞争的T细胞则不会。值得注意的是，我们的数据表明，MCMV特异性的TRM细胞对不经历记忆膨胀的T细胞具有丰富的作用。因此，我们将确定失败的T细胞 为了竞争MCMV抗原，优先在TRM池中浓缩。总之，这些实验将确定MCMV特异性TRM细胞的个体发育和功能，这些细胞驻留在疱疹病毒脱落的这些关键粘膜部位。

DESCRIPTION (provided by applicant): Cytomegalovirus (CMV) is a ubiquitous herpesvirus that establishes a systemic, persistent infection. CMV rarely causes serious disease in humans because systemic, life-long immune surveillance keeps the virus in check. In fact, CMV stimulates the largest known T cell populations in the circulation of humans. These T cells accumulate over time in a process called "memory inflation" and control CMV by shutting down viral reactivation from latency. For these reasons, CMV may serve as a tool for new vaccines against diseases such as cancer and HIV. However, CMV can cause devastating disease in a developing fetus when the virus is transmitted to a pregnant woman. Thus, a vaccine to prevent CMV transmission is rated as a highest priority by the Institute of Medicine. Understanding immune surveillance at sites of viral shedding will be key to preventing transmission and CMV disease. Recent work has shown that a T cell population called "resident memory" T cells (TRM) are established at sites in the body that may face viral reactivation. Indeed, TRM cells may help control herpesvirus reactivation. However, there have been no studies of CMV-specific TRM cells. Using the natural mouse herpesvirus, murine (M)CMV, our data show that many MCMV-specific TRM cells developed in the salivary and mammary glands - two sites from which HCMV and MCMV are known to be shed. More broadly, the salivary and mammary glands are two sites from which several human herpesviruses are shed. The ontogeny and function of TRM cells is poorly defined, and this gap is critical because these T cells are best positioned and possibly critical for controlling herpesvirus reactivation. Moreover, the promotion of such "first responders" - cells positioned at the site of pathogen invasion - is the major advantage of CMV- vectored vaccines. Aim 1: We will determine whether MCMV-specific TRM cells control viral latency and whether vaccines that elicit TRM formation will limit viral replication. Aim 2: Both repeated antigen recognition and the local cytokine environment are thought to modulate TRM development. Critically, infection with a spread-defective ¿gL-MCMV, which cannot spread to the salivary gland, increased the formation of salivary gland MCMV-specific TRM cells, implying that viral replication or repeated antigen recognition by T cells antagonizes TRM development. We will distinguish between these possibilities using a series of recombinant viruses. Aim 3: Our preliminary data show that memory inflation in circulation is driven by a competition for viral antigen. T cells that successfully compete, inflate; those that fil to compete do not. Remarkably, our data suggest that MCMV-specific TRM cells were enriched for T cells that do not undergo memory inflation. Thus, we will determine whether T cells that fail to compete for MCMV antigen are preferentially enriched in the TRM pool. Together, these experiments will determine the ontogeny and function of MCMV-specific TRM cells that reside at these critical mucosal sites of herpesvirus shedding.