- Reinink, Peter;
- Shahine, Adam;
- Gras, Stephanie;
- Cheng, Tan-Yun;
- Farquhar, Rachel;
- Lopez, Kattya;
- Suliman, Sara A;
- Reijneveld, Josephine F;
- Le Nours, Jérôme;
- Tan, Li Lynn;
- León, Segundo R;
- Jimenez, Judith;
- Calderon, Roger;
- Lecca, Leonid;
- Murray, Megan B;
- Rossjohn, Jamie;
- Moody, D Branch;
- Van Rhijn, Ildiko
High-throughput TCR sequencing allows interrogation of the human TCR repertoire, potentially connecting TCR sequences to antigenic targets. Unlike the highly polymorphic MHC proteins, monomorphic Ag-presenting molecules such as MR1, CD1d, and CD1b present Ags to T cells with species-wide TCR motifs. CD1b tetramer studies and a survey of the 27 published CD1b-restricted TCRs demonstrated a TCR motif in humans defined by the TCR β-chain variable gene 4-1 (TRBV4-1) region. Unexpectedly, TRBV4-1 was involved in recognition of CD1b regardless of the chemical class of the carried lipid. Crystal structures of two CD1b-specific TRBV4-1+ TCRs show that germline-encoded residues in CDR1 and CDR3 regions of TRBV4-1-encoded sequences interact with each other and consolidate the surface of the TCR. Mutational studies identified a key positively charged residue in TRBV4-1 and a key negatively charged residue in CD1b that is shared with CD1c, which is also recognized by TRBV4-1 TCRs. These data show that one TCR V region can mediate a mechanism of recognition of two related monomorphic Ag-presenting molecules that does not rely on a defined lipid Ag.