It can separate between what's part of yourself and what's foreign, and it does that by presenting, by recognizing antigens that are presented in the context of the major histocompatibility complex, MHC.

免疫系统可以识别出哪些是属于你的,哪些是外来的,它通过呈递和识别抗原达到目的,而抗原是存在于,主要组织相容性复合体中的

耶鲁公开课 - 生物医学工程探索课程节选