Regulatory role of heat shock protein-specific T cells in host defense.

During infection with L.monocytogenes, a facultative intracellular bacteria, TcR gamma/delta T cells specific for 65 kd hsp precede TcR alpha/beta T cells specific for the listerial antigens in appearance. The gamma/delta T cells provide a first line of defense against the infection by recognizing exogenous and endogenous 65 kd hsp on infected cells and producing cytokines such as gamma IFN. The hsp-specific T cells respond quickly to antigenically diverse pathogens before antigen-specific T cells expand clonally, and they play a role in covering the gap between the phagocytic system and highly evolved immune response. 65 kd hsp-specific T cells play important roles not only in host defense mechanism against infection with various pathogens but also in induction of auto-immune disease. Both 65 kd hsp-specific gamma delta T cells and 65 kd hsp-specific alpha beta T cells abrogate the unresponsiveness of the self-reactive alpha beta T cells and/or B cells by producing IL-2 and contribute to induction of autoimmune disease.