Superantigen recognition by γδ T cells:: SEA recognition site for human Vγ2 T cell receptors

Human gamma delta T cells expressing the V gamma 2V delta2 antigen receptors recognize nonpeptide prenyl pyrophosphate and alkylamine antigens. We find that they also recognize staphylococcal enterotoxin A superantigens in a manner distinct from the recognition of nonpeptide antigens. Using chimeric and mutant toxins, SEA amino acid residues 20-27 were shown to be required for gamma delta TCR recognition of SEA. Residues at 200-207 that are critical for specific alpha beta TCR recognition of SEA do not affect gamma delta TCR recognition. SEA residues 20-27 are located in an area contiguous with the binding site of V beta chains. This study defines a superantigen recognition site for a gamma delta T cell receptor and demonstrates the differences between V gamma 2V delta2(+) T cell recognition of superantigens and nonpeptide antigens.