The fidelity, occasional promiscuity, and versatility of T cell receptor recognition

Although there are multiple structures showing how alphabeta T cell receptors (TCRs) specifically recognize antigenic peptides bound to the major histocompatibility complex (MHC) molecules (pMHC-I and pMHC-II), we have little data on how TCRs interact with lipid-based antigens presented by members of the CD1 family. Here, we review recent findings in the field of TCR recognition, including TCR-pMHC complexes and the structure of a TCR in complex with CD1d-glycolipid. Collectively, these studies have revealed the versatility of the TCR in recognizing the distinct yet evolutionarily related proteinaceous and lipid-presenting molecules of the immune system.