A Population of Murine γδ T Cells That Recognize an Inducible MHC Class Ib Molecule

Although γδ T cells are implicated in regulating immune responses, γδ T cell-ligand pairs that could mediate such regulatory functions have not been identified. Here, the expression of the major histocompatibility complex (MHC) class Ib T22 and the closely related T10 molecules is shown to be activation-induced, and they confer specificity to about 0.4% of the γδ T cells in normal mice. Thus, the increased expression of T22 and/or T10 might trigger immunoregulatory γδ T cells during immune responses. Furthermore, the fast on-rates and slow off-rates that characterize this receptor/ligand interaction would compensate for the low ligand stability and suggest a high threshold for γδ T cell activation.