Characterization of Human T Cells Against Chlamydia

描述(申请人提供)：沙眼衣原体(CT)是全世界细菌性传播疾病的最常见原因。在大多数感染者中，他们是无症状的。这给妇女带来了健康风险，导致盆腔炎和输卵管不孕，以及来自受感染母亲的新生儿。我们的目标是研究人类T细胞对Ct的免疫应答，以确定可用于疫苗开发的免疫原性蛋白和多肽。我们将确定是否可以针对进入MHC I类或II类抗原处理途径或可能进入这些途径的Ct蛋白激发CD4或CD8T细胞反应。这些蛋白质的特定多肽表位和呈现这些多肽的人类白细胞抗原同种异型将使用一组独特的表达单个人类白细胞抗原的B淋巴母细胞系来确定。我们的假设是，免疫原性蛋白的某些区域将包含CD4和CD8T细胞的表位簇，就像我们在主要外膜蛋白MOMP中发现的那样。Ct特异性T细胞的功能特征将使用针对细胞因子、参与细胞毒作用的蛋白质和细胞表面分子的抗体来确定。将使用溶斑法等检测方法来确定CTL功能。感染者血液中的CT特异性T细胞将用MHC I类四聚体和II类四聚体计数。我们将确定识别Ct抗原的CD8T细胞是功能CTL细胞还是潜在的缺乏CTL活性的“耗尽”T细胞，这在慢性病毒感染中已经被发现。免疫原性表位交叉保护其他Ct物种的潜力将通过序列比较来确定，如肺炎支原体和鹦鹉热杆菌。表征人类T细胞对CT的反应对于了解人类对CT的免疫以及未来的疫苗开发具有重要意义。

DESCRIPTION (provided by applicant): Chlamydia trachomatis (Ct) is the most common cause of bacterial sexually transmitted disease worldwide. In the majority of infected individuals they are asymptomatic. This poses a heath risk for women, causing pelvic inflammation and tubal infertility, and for newborns from infected mothers. Our goal is to characterize the human T cell immune response to Ct in infected individuals with the goal of identifying immunogenic proteins and peptides that could be used for vaccine development. We will determine whether CD4 or CD8 T cell responses can be elicited against Ct proteins that enter the MHC class I or class II antigen processing pathway or are likely to enter those pathways. Specific peptide epitopes from these proteins and the HLA allotypes that present the peptides will be determined using a unique panel of B lymphoblastoid lines expressing single HLA antigens. Our hypothesis is that some regions of immunogenic proteins will contain epitope clusters for both CD4 and CD8 T cells as we found for the major outer membrane protein MOMP. The functional characteristics of the Ct-specific T cells will be determined using antibodies against cytokines, proteins involved in cytotoxicity, and cell surface molecules. Assays such as the Lysispot assay will be used to determine CTL function. Ct-specific T cells in the blood of infected individuals will be enumerated with MHC class I tetramer and class II tetramers. We will determine if the CD8 T cells recognizing Ct antigens are functional CTL cells or potentially "exhausted" T cells lacking CTL activity, which has been found in chronic viral infections. The potential for immunogenic epitopes to cross-protect other Ct species such as C. pneumonia and C. psittaci will be determined by sequence comparisons. Characterizing human T cell responses to Ct is important for understanding immunity to Ct in humans and for future vaccine development.