Epithelial cells in barrier tissues perform a critical immune function by detecting, restricting, and often directly eliminating extrinsic pathogens. Membrane-bound and cytosolic pattern recognition receptors in epithelial cells bind to diverse ligands, detecting pathogen components and behaviors and stimulating cell-autonomous immunity. In addition to directly acting as first-responders to pathogens, epithelial cells detect commensal-derived and diet-derived products to promote homeostasis. Recent advances have clarified the array of molecular sensors expressed by epithelial cells, and how epithelial cells responses are wired to promote homeostatic balance while simultaneously allowing elimination of pathogens. These new studies emphatically position epithelial cells as central to an effective innate immune response.

屏障组织中的上皮细胞通过检测、限制并经常直接消除外来病原体来发挥关键的免疫功能。上皮细胞中的膜结合和胞质模式识别受体与多种配体结合，检测病原体成分​​和行为并刺激细胞自主免疫。除了直接作为病原体的第一反应者外，上皮细胞还检测共生和饮食衍生的产品以促进体内平衡。最近的进展阐明了上皮细胞表达的分子传感器阵列，以及上皮细胞反应如何连接以促进稳态平衡，同时允许消除病原体。这些新研究强调将上皮细胞定位为有效先天免疫反应的核心。