Does Antibody-Dependent Intracellular Neutralization Limit HSV-1 Reactivation?

不促进病原体原位破坏或阻止其内化至靶细胞的抗体 然而，通过调理作用的免疫是对抗细胞内病原体的关键因素。一个重要机制 这种“非中和”抗体（nNAb）通过其减少某些感染已经被最近的研究所阐明。 抗体依赖性细胞内中和（ADIN）的发现。在ADIN中，与病原体结合的胞质nNAb是 该复合物被细胞内高亲和力Fc受体Trim 21识别，并且该复合物被蛋白酶体降解。Adin 已经发现能够根除包膜病毒。鉴于包膜病毒在细胞上释放结合的抗体， 膜融合，nNAb进入胞质溶胶的方式是令人困惑的。nNAb在体内进入胞质溶胶， 表明培养模型缺乏nNAb进入的关键细胞或因子。 单纯疱疹病毒（HSV）-1和-2最初在粘膜表面以裂解方式复制，但随后建立生命- 长期驻留在周围神经系统的神经节神经元内。病毒基因组进入神经细胞核 潜伏期，一种静止状态，其中复制受到抑制，裂解蛋白以几乎检测不到的水平产生。 由于成熟的神经元是不可再生的，不受控制的病毒复制可导致中枢神经系统损伤， 对等待时间的控制对于主机是关键的。神经节由CD 8 + T细胞监测，该细胞在神经节细胞中递送颗粒酶B。 通过穿孔素孔与感染的神经元形成免疫突触。胞浆颗粒酶B抑制ICP 4，一种必需的 转录调节因子因此，该模型是，在没有ICP 4上调转录产物的情况下，潜伏期是 永存我们的数据表明，ICP 4抗体存在于血清阳性的人三叉神经节，提示检查 通过颗粒酶B和可能通过介导其ADIN的ICP 4抗体表达ICP 4。 我们假设ICP 4的抗体依赖性细胞内中和限制了HSV-1的再活化。我们将 在两个特定目的的实验中解决这个问题：1）评估抗体是否通过以下途径进入神经元胞质： CD 8 +-T细胞和潜伏感染的神经元之间的密切相互作用;以及2）确定非中和性T细胞是否与潜伏感染的神经元之间的相互作用。 抗体指导潜伏性神经元感染期间产生的ICP 4的ADIN，抑制病毒再活化。我们将使用收敛 从人HSV-1潜伏期的体内→离体小鼠模型和人HSV-1潜伏期的体外模型中获益的方法。 人诱导多能干细胞衍生神经元中潜伏HSV-1感染如果成功，目标1将定义一个 在HSV-1潜伏期的背景下，nNAb进入细胞的途径迄今未描述。目的2将阐明分子 病毒潜伏期和宿主免疫力之间复杂平衡的基础。如果成功的话，这项R21研究将把重点转移到 HSV疫苗靶向设计以适应ADIN在抗病毒免疫中的作用，并表明潜在的治疗作用 靶点包括再激活抑制剂或ADIN激动剂。我们研究的进展也可以为深远的 拮抗具有潜伏状态的人类病原体包括HIV、HCMV、MeV和EBV的方法。

Antibodies that do not promote the destruction of pathogens in situ or prevent their internalization into target cells through opsonization are nevertheless key factors in immunity against intracellular pathogens. An important mechanism by which such “non-neutralizing” antibodies (nNAbs) curtail certain infections has been illuminated by the recent discovery of antibody-dependent intracellular neutralization (ADIN). In ADIN, cytosolic nNAbs bound to pathogens are recognized by the intracellular high-affinity Fc receptor Trim21 and the complex is degraded by the proteasome. ADIN has been found capable of eradicating an enveloped virus. Given that enveloped viruses shed bound antibodies upon cell membrane fusion, the means by which nNAbs access the cytosol is puzzling. That nNAbs access the cytosol in vivo but not in vitro suggests that culture models lack a critical cell or factor for nNAb entry. Herpes simplex viruses (HSV)-1 and -2 initially replicate in a lytic manner at mucosal surfaces but then establish life- long residence within ganglion neurons of the peripheral nervous system. In neuronal nuclei the viral genome enters latency, a state of quiescence in which replication is repressed and lytic proteins are produced at near-undetectable levels. As mature neurons are non-renewable and unchecked viral replication can lead to central nervous system damage, the control of latency is critical to the host. Ganglia are monitored by CD8+ T-cells, which deliver granzyme B at the immunological synapse with infected neurons via perforin pores. Cytosolic granzyme B digests ICP4, an essential transcriptional regulator. The model is therefore that without ICP4 to upregulate transcript production, latency is perpetuated. Our data show that ICP4 antibodies exist in seropositive human trigeminal ganglia, suggestive of a check on ICP4 expression by granzyme B and possibly by antibodies to ICP4 that mediate its ADIN. We hypothesize that antibody-dependent intracellular neutralization of ICP4 limits HSV-1 reactivation. We will address this in experiments of two Specific Aims: 1) assess whether antibodies gain access to the neuronal cytosol through the close interaction between CD8+-T-cells and latently-infected neurons; and 2) determine whether non-neutralizing antibodies direct ADIN of ICP4 produced during latent neuronal infection, stifling viral reactivation. We will use convergent approaches to benefit from both an in vivo → ex vivo mouse model of human HSV-1 latency, and an in vitro model of latent HSV-1 infection in human induced pluripotent stem cell-derived neurons. If successful, Aim 1 will define a heretofore undescribed route of nNAb entry into cells in the context of HSV-1 latency. Aim 2 will elucidate the molecular basis of the complex balance between viral latency and host immunity. If successful, this R21 study will shift the focus of HSV vaccine target design to accommodate a role for ADIN in anti-viral immunity, and indicate potential therapeutic targets including inhibitors of reactivation, or agonists of ADIN. Advances from our studies could also inform far-reaching approaches to antagonize human pathogens with a latency state including HIV, HCMV, MeV, and EBV.