CMV pentameric complex based vaccine strategies for prevention of congenital CMV

摘要 由于先天性巨细胞病毒（CMV）感染的风险，巨细胞病毒（CMV）疫苗的开发是一个主要的公共卫生优先事项。 感染人CMV（HCMV）的临床株与实验室适应的病毒不同，因为临床株表达一种与实验室适应的病毒不同的抗原。 五聚体复合物（PC），并保留感染上皮细胞和内皮细胞的能力，不像实验室菌株， 仅限于成纤维细胞。病毒进入epi/内皮细胞的机制与gB不同 进入成纤维细胞的途径，因为它需要病毒蛋白gH/gL/UL 128 -131形成内吞 复合物（PC）以使病毒能够进入细胞。重要的是，经胎盘CMV感染高度依赖于 由于病毒必须感染血管的内皮细胞（母体和 胎儿）以及构成胎盘一部分的上皮滋养体细胞层。中和抗体 PC的抗体可能比免疫显性gB糖蛋白的抗体更重要，因为抗- 与gB相比，PC抗体在中和表皮/内皮细胞上的病毒方面更有效。重要的是在 恢复期患者的高抗PC滴度被认为有效预防先天性CMV。人类 由于种属特异性，CMV不能在动物模型中直接研究。豚鼠是唯一 允许研究先天性CMV但需要使用种属特异性豚鼠的小动物模型 CMV（GPCMV）。在先天性CMV豚鼠模型中，我们定义了一个同源五聚体复合物， 是GPCMV的上皮嗜性、病毒传播和先天性感染所必需的。而且 GPCMV同源物PC具有高度免疫原性，并产生中和病毒感染的抗体。 上皮细胞这项临床前转化研究旨在开发GPCMV PC特异性疫苗策略 （基于亚单位或缺陷型腺病毒载体），以确定PC或PC亚复合物疫苗策略 可预防豚鼠模型中的先天性CMV。重要的是，作为这些研究的一部分， PC疫苗对来自不同GPCMV毒株的先天性CMV交叉保护的能力。另夕h 将评价gB和PC疫苗策略协同作用。最后，由于HCMV中gB和gH 诱导CD 4 T细胞应答，将评价T细胞应答的保护性影响。

Abstract Development of a cytomegalovirus (CMV) vaccine is a major public health priority due to the risk of congenital infection. Clinical strains of human CMV (HCMV) differ from lab adapted virus as the clinical strains express a pentameric complex (PC) and retain the ability to infect epithelial and endothelial cells unlike lab strains which are limited to fibroblast cells. The mechanism of virus entry into epi/endothelial cells is different from the gB pathway of entry into fibroblast cells as it requires viral proteins gH/gL/UL128-131 forming an endocytic complex (PC) to enable viral cell entry. Importantly, transplacental CMV infection is highly dependent upon viral epithelial/endothelial tropism since the virus has to infect endothelial cells of blood vessels (maternal and fetal) as well as a layer of epithelial trophoplast cells that constitute part of the placenta. Neutralizing antibodies to the PC are potentially more important than antibodies to the immunodominant gB glycoprotein, since anti- PC antibodies are more effective in neutralizing virus on epi/endothelial cells compared to gB. Importantly, in convalescent patients high anti-PC titers are thought to be effective in preventing congenital CMV. Human CMV cannot be directly studied in an animal model because of species specificity. The guinea pig is the only small animal model that allows the study of congenital CMV but requires the use of species specific guinea pig CMV (GPCMV). In the guinea pig model for congenital CMV, we have defined a homolog pentameric complex as necessary for epithelial tropism, virus dissemination and congenital infection by GPCMV. Furthermore, the GPCMV homolog PC is highly immunogenic and generates antibodies that neutralize virus infection on epithelial cells. This pre-clinical translational study seeks to develop GPCMV PC specific vaccine strategies (either subunit or defective adenovirus vector based) to determine if a PC or PC subcomplex vaccine strategy can prevent congenital CMV in the guinea pig model. Importantly, as part of these studies we will evaluate the ability of PC vaccines to cross protect against congenital CMV from different GPCMV strains. Additionally, the synergy effect of gB and PC vaccine strategies will be evaluated. Finally, since in HCMV both gB and gH induce a CD4 T cell response, the protective impact of the T cell response will be evaluated.