The CD1 family of antigen-presenting molecules adopt a major histocompatibility complex class I (MHC-I) fold. Whereas MHC molecules present peptides, the CD1 family has evolved to bind self- and foreign-lipids. The CD1 family of antigen-presenting molecules comprises four members—CD1a, CD1b, CD1c, and CD1d—that differ in their architecture around the lipid-binding cleft, thereby enabling diverse lipids to be accommodated. These CD1–lipid complexes are recognized by T cell receptors (TCRs) expressed on T cells, either through dual recognition of CD1 and lipid or in a new model whereby the TCR directly contacts CD1, thereby triggering an immune response. Chemical syntheses of lipid antigens, and analogs thereof, have been crucial in understanding the underlying specificity of T cell–mediated lipid immunity. This review will focus on our current understanding of how TCRs interact with CD1–lipid complexes, highlighting how it can be fundamentally different from TCR-MHC-peptide corecognition.

中文翻译：

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T 细胞受体如何识别脂质抗原呈递分子 CD1 家族的结构视角


CD1 抗原呈递分子家族采用主要组织相容性复合物 I 类 (MHC-I) 折叠。 MHC 分子呈现肽，而 CD1 家族已进化为结合自身和外来脂质。 CD1 抗原呈递分子家族包括四个成员：CD1a、CD1b、CD1c 和 CD1d，它们在脂质结合裂口周围的结构不同，从而能够容纳不同的脂质。这些 CD1-脂质复合物被 T 细胞上表达的 T 细胞受体 (TCR) 识别，或者通过 CD1 和脂质的双重识别，或者在 TCR 直接接触 CD1 的新模型中，从而触发免疫反应。脂质抗原及其类似物的化学合成对于理解 T 细胞介导的脂质免疫的潜在特异性至关重要。本综述将重点关注我们目前对 TCR 如何与 CD1-脂质复合物相互作用的理解，强调它与 TCR-MHC-肽核心认知的根本不同。