MHC tetramers for epitopes of B anthracis PA

描述(申请人提供)：美国已承诺为大量人接种炭疽疫苗。然而，人们普遍认识到当前炭疽疫苗的局限性，并正在努力改进疫苗配方。我们将创建炭疽疫苗接种反应的生物标记和预测因子，长期临床目标是设计更安全、更有效的疫苗。为了实现这一目标，我们将开发新的人类II类MHC四聚体，以识别针对炭疽杆菌保护性抗原(BAPA)的抗原特异性CD4+T细胞。炭疽疫苗接种后四聚体阳性T细胞的数量和表型将作为细胞免疫的指标进行评估。 具体目标是： 目的1.鉴定炭疽杆菌保护性抗原(BAPA)的免疫优势表位，该表位可被CD4T细胞识别，具有较强的免疫原性。 目的2.用可溶性人类白细胞抗原-BAPA四聚体定量检测炭疽疫苗免疫后CD4T细胞的免疫应答。 将根据T细胞对一组受限的BAPA表位识别的多肽的选择，生产和评估涵盖大多数流行的人类II类单倍型的四聚体。该项目的MHC-肽结合分析、四聚体生产和检测方法以及表位扫描技术都得到了验证，使用转基因小鼠替代品对BAPA的T细胞反应的初步数据表明，在接种疫苗后成功地检测到了应答的抗原特异性群体。

DESCRIPTION (provided by applicant): A commitment has been made in the USA to vaccinate large numbers of persons against anthrax. However, limitations of the current anthrax vaccine are widely acknowledged, and efforts are underway to improve the vaccine formulation. We will create biological markers and predictors of the response to anthrax vaccination, with the long-term clinical goal of designing safer and more effective vaccines. To achieve this objective, we will develop novel human class II MHC tetramers which identify antigen-specific CD4+ T cells specific for bacillus anthrax Protective Antigen (BAPA). Quantitation and phenotyping of the tetramer-positive T cells following anthrax vaccination will be evaluated as an indicator of cellular immunity. The Specific Aims are: Aim 1. To identify immunodominant epitopes of bacillus anthrax Protective Antigen (BAPA) based on HLA class II binding and recognized by CD4 T cells which are capable of eliciting robust immunity. Aim 2. To use soluble HLA-BAPA tetramers to quantify the CD4 T cell response to anthrax vaccination. Tetramers will be produced and evaluated which encompass most of the prevalent human class II haplotypes, based on selection of peptides corresponding to T cell recognition of a restricted set of BAPA epitopes. MHC-peptide binding assays, tetramer production and testing methods, and epitope scanning technologies for this project are all validated, and preliminary data using transgenic murine surrogates for the T cell response to BAPA demonstrate successful detection of the responding antigen-specific population following vaccination.