A single T cell receptor recognizes structurally distinct MHC/peptide complexes with high specificity.
The 2C T cell is a CD8+, alloreactive T cell, which recognizes cells bearing Ld and Kbm3 class I major histocompatability complex molecules. Here, we characterize an allopeptide, designated dEV-8, that is a ligand in the Kbm3 molecule for the 2C TCR but is not a ligand in the Ld molecule. By biochemical and immunological properties, dEV-8 is distinct from P2Ca, the Ld allopeptide that is also recognized by the 2C TCR. Using the deduced amino acid sequence of dEV-8, we isolate a candidate endogenous source of the peptide. The endogenous protein, MLRQ, contains a peptide sequence identical to dEV-8. This degenerate recognition of two distinct peptide/MHC complexes by a single TCR has important implications for understanding allorecognition.
Tallquist
M D
MD
Department of Immunology, Mayo Foundation, Rochester, Minnesota 55905, USA.
Yun
T J
TJ
Pease
L R
LR
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D007519:Isoantigens / Q000737:chemistry / Q000302:isolation & purification*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D012689:Sequence Homology, Nucleic Acid; D013379:Substrate Specificity
D015395:Histocompatibility Antigens Class I; D007519:Isoantigens; D011948:Receptors, Antigen, T-Cell