Epitopes, in the context of T cell recognition, are short peptides typically derived by antigen processing, and presented on the cell surface bound to MHC molecules (HLA molecules in humans) for TCR scrutiny. The identification of epitopes is a context-dependent process, with consideration given to, for example, the source pathogen and protein, the host organism, and state of the immune reaction (e.g., following natural infection, vaccination, etc.). In the following review, we consider the various approaches used to define T cell epitopes, including both bioinformatic and experimental approaches, and discuss the concepts of immunodominance and immunoprevalence. We also discuss HLA polymorphism and epitope restriction, and the resulting impact on the identification of, and potential population coverage afforded by, epitopes or epitope-based vaccines. Finally, some examples of the practical application of T cell epitope identification are provided, showing how epitopes have been valuable for deriving novel immunological insights in the context of the immune response to various pathogens and allergens.

在 T 细胞识别的背景下，表位是通常由抗原加工衍生的短肽，并呈现在与 MHC 分子（人类中的 HLA 分子）结合的细胞表面上，用于 TCR 审查。表位的鉴定是一个上下文相关的过程，考虑到例如来源病原体和蛋白质、宿主生物体和免疫反应的状态（例如，在自然感染、疫苗接种后等）。在下面的综述中，我们考虑用于定义 T 细胞表位的各种方法，包括生物信息学和实验方法，并讨论免疫优势和免疫流行的概念。我们还讨论了 HLA 多态性和表位限制，以及由此产生的对鉴定和潜在人口覆盖率的影响，表位或基于表位的疫苗。最后，提供了 T 细胞表位鉴定实际应用的一些例子，展示了表位如何在对各种病原体和过敏原的免疫反应的背景下获得新的免疫学见解的价值。