PKC delta is involved in signal attenuation in CD3 super(+) T cells

PKC delta has been implicated in the signalling events after engagement of the antigen specific receptor on B cells and the Fc- epsilon receptor on mast cells. Employing our recently established PKC delta null mice , we here investigate the physiological function of PKC delta in CD3 super(+) T cells. As result, administration of anti-CD3 antibodies in vivo induced markedly increased blood plasma IL-2 levels (but not IL-4, IFN- plus or minus , TNF- alpha and IL-6 levels) in the PKC delta null mice, when compared to wild-type sibling controls. Additionally, in vitro T cell proliferative responses to allogenic MHC are significantly enhanced in PKC delta -deficient CD3 super(+) T cells. These findings suggest that PKC delta serves a so far unrecognized role in TCR-induced negative regulation of IL-2 cytokine production and T cell proliferation.