Antigen recognition properties of mutant Vβ3⁺ T cell receptors are consistent with an immunoglobulin-like structure for the receptor

We examined the effect of mutations in the Vβ portion of a pigeon cytochrome c (cyto c)-specific Vβ3⁺/Vα11⁺ T cell receptor on its ability to recognize cyto c/IE^k and various superantigens. The results were consistent with an immunoglobulin-like structure for the receptor Vβ domain and with separate interaction sites on Vβ for conventional antigen and superantigens. An amino acid predicted to lie in CDR1 was critical for cyto c/IE^k but not superantigen recognition, while several amino acids predicted to lie in the hypervariable region 4 loop were critical for superantigen but not cyto c/IE^k recognition.