T lymphocytes comprise cells expressing either an αβ or a γδ TCR. The riddle how αβ TCRs are triggered by specific peptides presented in the context of MHC was elucidated some time ago. In contrast, the mechanisms that underlie antigen recognition by γδ TCRs are still baffling the scientific community. It is clear that activation of γδ TCRs does not necessarily depend on MHC antigen presentation. To date, diverse and largely host-cell-derived molecules have been identified as cognate antigens for the γδ TCR. However, for most γδ TCRs, the activating ligand is still unknown and many open questions with regard to physiological relevance and generalizable concepts remain. Especially the question of how γδ T cells can distinguish homeostatic from stress conditions via their TCR remains largely unresolved. Recent discoveries in the field might have paved the way towards a better understanding of antigen recognition by the γδ TCR and have made it conceivable to revise the current knowledge and contextualize the new findings.

T 淋巴细胞包含表达 αβ 或 γδ TCR 的细胞。 MHC 背景下的特定肽如何触发 αβ TCR 的谜团不久前已被阐明。相比之下，γδ TCR 识别抗原的机制仍然困扰着科学界。很明显，γδ TCR 的激活不一定依赖于 MHC 抗原呈递。迄今为止，多种主要源自宿主细胞的分子已被鉴定为 γδ TCR 的同源抗原。然而，对于大多数 γδ TCR 来说，激活配体仍然未知，并且关于生理相关性和普遍概念的许多悬而未决的问题仍然存在。尤其是 γδ T 细胞如何通过 TCR 区分稳态和应激条件的问题在很大程度上仍未得到解决。该领域的最新发现可能为更好地理解 γδ TCR 的抗原识别铺平了道路，并使得修改当前知识并将新发现置于背景中成为可能。