Yang Junbao, James Eddie, Roti Michelle, Huston Laurie, Gebe John A, Kwok William W
Benaroya Research Institute at Virginia Mason, Seattle, WA, USA.
Int Immunol. 2009 Jan;21(1):63-71. doi: 10.1093/intimm/dxn124. Epub 2008 Dec 2.
Identification of dominant T cell epitopes within newly emerging and re-emerging infectious organisms is valuable in understanding pathogenic immune responses and potential vaccine designs. However, difficulties in obtaining samples from patients or convalescent subjects have hampered research in this direction. We demonstrated a strategy, tetramer-guided epitope mapping, that specific CD4+ T cell epitopes can be identified by using PBMC from subjects that have not been exposed to the infectious organism. Sixteen HLA-DR0401- and 14 HLA-DR0701-restricted epitopes within spike protein of severe acute respiratory syndrome-coronavirus (SARS-CoV) were identified. Among these, spike protein residues 159-171, 166-178, 449-461 and 1083-1097 were identified to contain naturally processed immunodominant epitopes based on strong in vitro T cell responses of PBMC (as assayed by tetramer staining) to intact spike protein stimulation. These immunodominant epitopes were confirmed in vivo in HLA-DR0401 transgenic mice by immunizing with spike protein. Furthermore, the epitope-specific T cells from naive donors secreted IFN-gamma and IL-13 upon re-stimulation with corresponding tetramers. Our study demonstrates a strategy to determine potential immunodominant epitopes for emerging infectious pathogens prior to their epidemic circulation.
识别新出现和再次出现的传染性生物体中的主要T细胞表位，对于理解致病性免疫反应和潜在的疫苗设计具有重要价值。然而，从患者或康复个体获取样本存在困难，这阻碍了该方向的研究。我们展示了一种策略，即四聚体引导的表位图谱分析，通过使用未接触过传染性生物体的个体的外周血单核细胞（PBMC），可以识别特定的CD4+ T细胞表位。在严重急性呼吸综合征冠状病毒（SARS-CoV）的刺突蛋白中，鉴定出了16个HLA-DR0401限制性表位和14个HLA-DR0701限制性表位。其中，基于PBMC（通过四聚体染色检测）对完整刺突蛋白刺激的强烈体外T细胞反应，确定刺突蛋白残基159 - 171、166 - 178、449 - 461和1083 - 1097含有天然加工的免疫显性表位。通过用刺突蛋白免疫HLA-DR0401转基因小鼠，在体内证实了这些免疫显性表位。此外，来自未接触过抗原的供体的表位特异性T细胞在用相应四聚体再次刺激时分泌干扰素-γ和白细胞介素-13。我们的研究展示了一种在新出现的传染性病原体流行传播之前确定其潜在免疫显性表位的策略。
