VARICELLA ZOSTER VIRUS--T CELL/SKIN TROPISMS AND IMMUNIT

水痘-带状疱疹病毒(VZV)引起水痘和带状疱疹。我们的目标是提高对这种常见病原体如何致病以及自然和疫苗诱导免疫提供保护的知识。糖蛋白可能是T细胞和皮肤的宿主范围决定因素，而T细胞和皮肤是VZV感染的关键靶细胞。我们的重点是糖蛋白，GI(ORF67)和GE(ORF68)。在宇宙中产生的GI或GE突变对VZV复制的影响将在体外确定。VZV致病的SCIDhu小鼠模型将在体内评估VZV对人类CD4和CD8 T细胞或皮肤的感染性，这揭示了VZV蛋白在组织培养中完全不可缺少的关键作用。也将使用绿色荧光蛋白(GFP)标记的VZV在胸腺器官培养和II23细胞(一种CD4T细胞杂交瘤)中研究T细胞的趋向性。VZV、GI和Ge对MDCK细胞上皮细胞的影响将在MDCK细胞中进行评估。疫苗株V-Oka将与其亲本P-Oka进行比较，以确定GE或GI突变是否可以解释V-Oka的衰减。VZV感染幼虫体内的T细胞，并在诱导VZV特异性免疫之前传播。我们已经发现VZV干扰主要组织相容性(MHC)I类和II类细胞表面的表达。我们的目标是识别使VZV逃避免疫监视的病毒免疫调节蛋白，并确定皮肤归巢受体是否促进受感染的T细胞向皮肤的运输。这些机制是否在自然感染期间在皮肤部位发挥作用，将在急性水痘皮损的活检中确定。快速获得VZV特异性T细胞反应与轻度水痘和潜伏期的维持有关。我们建议用新的方法来测量针对主要病毒蛋白GE和即时早期被盖/反式激活蛋白IE62的CD4和CD8T细胞应答频率，以解决有关VZV适应性免疫的重要问题。我们将检查自然免疫和疫苗诱导免疫提供的保护的差异，成人水痘疫苗的免疫原性降低，以及VZV T细胞反应随着年龄的增长而下降。将使用细胞内细胞因子分析来定量比较CD4和CD8对GE和IE62蛋白和多肽的识别。适合合成的多肽作为MHC I类和II类四聚体将被识别并用于计数CD4和CD8亚群中的VZV特异性应答T细胞。这些关于水痘病毒致病机制和免疫的平行研究与改进水痘减毒活疫苗的实际意义直接相关。

Varicella-zoster virus (VZV) causes varicella and herpes zoster. Our goal is to improve knowledge about how this common pathogen causes disease and about protection provided by natural and vaccine-induced immunity. Glycoproteins are likely to be host range determinants for T cells and skin, which are critical target cells during VZV infection. Our focus is on glycoproteins, gI (ORF67) and gE (ORF68). The effect of gI or gE mutations made in cosmids, on VZV replication will be determined in vitro. Infectivity for human CD4+ and CD8+ T cells or skin will be assessed in vivo in the SCIDhu mouse model of VZV pathogenesis, which reveals critical roles for VZV proteins that are completely dispensable in tissue culture. T cell tropism will also be investigated in thymic organ cultures and II23 cells, a CD4+ T cell hybridoma, using green fluorescent protein (gfp)-labeled VZV. VZV gI and gE effects on epithelial cells will be evaluated in MDCK cells. The vaccine strain, V-Oka, will be compared with its parent, P-Oka, to determine whether gE or gI mutations explain V-Oka attenuation. VZV infects T cells in the naive host and spreads before VZV specific immunity is induced. We have found that VZV interferes with cell surface expression of major histocompatibility (MHC) class I and class II. Our goals are to identify viral immunomodulatory proteins that allow VZV to escape from immune surveillance and to determine whether skin homing receptors facilitate transport of infected T cells to skin. Whether these mechanisms function at skin sites during natural infection will be determined in biopsies from acute varicella lesions. Rapid acquisition of VZV specific T cell responses correlates with mild varicella and maintenance of latency. We propose to address important questions about adaptive VZV immunity with new methods to measure CD4+ and CD8+ T cell responder frequencies against dominant viral proteins, gE and the immediate early tegument/transactivating protein, IE62. We will examine differences in protection afforded by natural and vaccine-induced immunity, diminished immunogenicity of varicella vaccine in adults, and declining VZV T cell responses with aging. Quantitative comparisons of CD4+ and CD8+ recognition of gE and IE62 protein and peptides will be made using intracellular cytokine assays. Peptides appropriate for synthesis as MHC class I and class II tetramers will be identified and used to enumerate VZV specific responder T cells in CD4+ and CD8+ subsets. These parallel investigations of VZV pathogenesis and immunity are directly linked by their practical relevance for improving live attenuated varicella vaccines.