Development of a universal DISC vaccine strategy against congenital cytomegalovirus

摘要 先天性巨细胞病毒(CCMV)是导致存活新生儿听力损失和认知障碍的主要原因。一个 疫苗是高度优先的，但有效的疫苗需要超过自然恢复期的保护水平 由于有可能再次感染多株人巨细胞病毒而产生免疫力。豚鼠是唯一的小的 与人类相似的幼鼠CCMV疾病的动物模型。此前，有证据表明，豚鼠 巨细胞病毒(GPCMV)编码功能类似于HCMV的基本病毒糖蛋白复合体，其 可作为中和抗体靶抗原。与HCMV的一个重要关联是GPCMV编码 病毒嗜性/进入非成纤维细胞所必需的基于Gh的功能性五聚体复合体(PC)， 致病机制和CCMV。此前，两个非复制能力衣壳突变体GPCMV的效力 DISC(缺陷感染性单循环)疫苗株的评价：(1)缺乏PC(DISCI)；(2)编码 PC(DISCII)。DISCII更成功地中和了上皮细胞上的病毒，并完全保护了 用野生型病毒攻击妊娠动物的CCMV。然而，一个重大挑战是 有待实现的是圆盘疫苗策略预防：(1)多毒株病毒的能力 挑战，这是成功的人巨细胞病毒疫苗的绝对必要；(2)提供保护，防止 自然的感染途径。一种新分离的GPCMV毒株(CRV)将包括在研究中，以使 多株病毒挑战。改良GPCMV圆盘疫苗株将提高免疫原性和 确定了免疫保护的相关因素。豚鼠模型研究的一个重要飞跃是我们将 利用第一基因敲除(IFNLR1)豚鼠评价干扰素III在形成免疫中的重要性 回应。总体的中心假设是，圆盘疫苗策略可以提供更大的保护 与恢复期免疫相比，可以完全预防多种病毒株和 自然的感染途径，但疫苗需要全面的CMV基因表达，而这可能是缺乏的 在IE1突变的圆盘疫苗株中。拟议的研究将提供一个更快的时间表 针对CCMV的圆盘疫苗策略的现实评估。

ABSTRACT Congenital CMV (cCMV) is a leading cause of hearing loss and cognitive impairment in surviving newborns. A vaccine is a high priority but an effective vaccine needs to exceed protection levels of natural convalescent immunity because of the risk of re-infection by multiple strains of HCMV. The guinea pig is the only small animal model for cCMV with disease in pups similar to humans. Previously it was demonstrated that guinea pig cytomegalovirus (GPCMV) encodes functionally similar essential viral glycoprotein complexes to HCMV, which can act as neutralizing antibody target antigens. An important correlation with HCMV is that GPCMV encodes a functional gH based pentamer complex (PC) necessary for virus tropism/entry to non-fibroblast cells, pathogenesis and cCMV. Previously, the efficacy of two non-replication competent capsid mutant GPCMV DISC (Defective Infectious Single Cycle) vaccine strains were evaluated: (1) lacking PC (DISCI); (2) encoding PC (DISCII). DISCII was more successful in neutralizing virus on epithelial cells and fully protected against cCMV when pregnant animals were challenged with wild type virus. However, a significant challenge that remains to be attained is the ability of a DISC vaccine strategy to protect against: (1) multistrain virus challenge, which is an absolute necessity for a successful HCMV vaccine; (2) provide protection against natural routes of infection. A newly isolated GPCMV strain (CRV) will be included in the studies to enable multistrain virus challenge. Modified GPCMV DISC vaccine strain will be improved for immunogenicity and correlates of immune protection determined. An important leap in the guinea pig model studies is that we will employ the first gene knockout (IFNLR1) guinea pig to evaluate the importance of IFN III in shaping immune response. The overall central hypothesis is that the DISC vaccine strategy can provide greater protection against cCMV compared to convalescent immunity and can fully protect against multiple strains of virus and natural routes of infection but vaccine requires comprehensive CMV gene expression that is potentially lacking in IE1 mutant based DISC vaccine strains. The proposed studies will provide an accelerated timeline for the realistic evaluation of a DISC vaccine strategy against cCMV.