Recognition of a peptide antigen by heat shock--reactive gamma delta T lymphocytes.

Small synthetic peptides that correspond to different portions of the 65-kilodalton mycobacterial heat shock protein (Hsp65) were used to identify a putative antigenic epitope for gamma delta cells. Weaker gamma delta responses to the equivalent portion of the autologous homolog, mouse Hsp63, were also seen. The stimulatory epitope overlaps with an epitope recognized by arthritogenic alpha beta T cell clones. The data suggest that gamma delta cells have a role in autoimmune disorders and imply that these cells recognize ligands by a mechanism similar to that of alpha beta T lymphocytes, that is, in the form of small processed protein fragments bound to antigen-presenting molecules.