Mucosal-associated invariant T (MAIT) cells are innate-like T cells present at considerable frequencies in human blood and barrier tissues, armed with an expanding array of effector functions in response to homeostatic perturbations. Analogous to other barrier immune cells, their phenotype and function is driven by crosstalk with host and dynamic environmental factors, most pertinently the microbiome. Given their distribution, they must function in diverse extracellular milieus. Tissue-specific and adapted functions of barrier immune cells are shaped by transcriptional programs and regulated through a blend of local cellular, inflammatory, physiological, and metabolic mediators unique to each microenvironment. This review compares the phenotype and function of MAIT cells with other barrier immune cells, highlighting potential areas for future exploration. Appreciation of MAIT cell biology within tissues is crucial to understanding their niche in health and disease.

粘膜相关不变 T (MAIT) 细胞是先天性 T 细胞，在人类血液和屏障组织中以相当高的频率存在，具有一系列不断扩大的效应功能以响应稳态扰动。与其他屏障免疫细胞类似，它们的表型和功能是由与宿主和动态环境因素（最相关的是微生物组）的串扰驱动的。鉴于它们的分布，它们必须在不同的细胞外环境中发挥作用。屏障免疫细胞的组织特异性和适应性功能由转录程序形成，并通过每个微环境特有的局部细胞、炎症、生理和代谢介质的混合来调节。这篇综述将 MAIT 细胞与其他屏障免疫细胞的表型和功能进行了比较，强调了未来探索的潜在领域。了解组织内的 MAIT 细胞生物学对于了解其在健康和疾病中的地位至关重要。