SELECTIVE INDUCTION OF CD8(-LYMPHOCYTE EFFECTOR FUNCTION BY STAPHYLOCOCCUS ENTEROTOXIN-B() CYTOTOXIC T)

Upon encounter with its antigenic stimulus, CTL characteristically pro liferate, produce cytokines, and lyse the Ag-presenting cell in an att empt to impede further infection. Superantigens are extremely efficien t immunostimulatory proteins that promote high levels of proliferation and massive cytokine production in reactive T cells. We compared the activation of murine influenza-specific CD8(+) CTL clones stimulated w ith either influenza peptide or the superantigen staphylococcus entero toxin B (SEB). We found that influenza peptide/MHC and SEE appeared eq ually capable of eliciting proliferation and IFN-gamma production. How ever, while influenza peptide/MHC elicited both perforin- and Fas liga nd (FasL)/Fas (CD95L/CD95)-mediated cytolytic mechanisms, SEE was unab le to trigger perforin-mediated cytolysis or serine esterase release. Examination of intracellular Ca2+ mobilization events revealed that th e ability to trigger intracellular Ca2+ flux was not comparable betwee n influenza peptide and SEE. SEE stimulated only a small rise in level s of intracellular Ca2+, at times indistinguishable from background. T hese findings indicate that the short-term cytolytic potential of supe rantigen-activated CD8(+) CTL clones appears to be restricted to FasL/ Fas (CD95L/CD95) mediated cytolysis.