Role of the T cell receptor alpha-chain in superantigen recognition.
Superantigens bind to antigen-presenting cells on the outside of the major histocompatibility complex (MHC) class II molecule and to T cells via the external face of the T cell receptor (TCR) V beta element. As a consequence, superantigens stimulate populations of T cells in a V beta-specific, non-MHC-restricted manner. However, accumulating evidence has shown an additional contribution of the TCR alpha-chain and polymorphic residues of the MHC molecule to superantigen recognition by some T cells. These data suggest that the TCR and MHC come into contact during superantigen engagement and indirectly modulate the superantigen reactivity. Thus, additional interactions between non-V beta elements of the TCR and MHC play a role in the overall stability of the superantigen/MHC/TCR complex, explaining the influence of the TCR alpha-chain. It is likely that this additional interaction is of greater consequence for weakly reactive T cells. This modulation of superantigen reactivity in individual T cells may have physiological consequences, for example, in the induction of autoimmunity.
Blackman
M A
MA
Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tenn. 38105, USA.
Woodland
D L
DL
D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D006801:Humans; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D018089:Superantigens / Q000276:immunology*
D016693:Receptors, Antigen, T-Cell, alpha-beta; D018089:Superantigens