CD8(-GAMMA AFTER SUPERANTIGEN STIMULATION() CELLS ARE THE MAIN PRODUCERS OF IL10 AND IFN)

Purified CD8(+) T cells were recently shown to produce TH1 as well as TH2 types of cytokines upon restimulation, indicating an important rol e for these cells in regulation of immune responses. However, it is no t known if the CD8(+) cells would contribute to cytokine production in the presence of cytokine secreting CD4(+) cells. In the present study the authors have investigated the proportion of cytokine-producing CD 4(+) and CD8(+) cells in the spleen after in vitro or in vivo stimulat ion. They found that stimulation of spleen cells with the superantigen Staphylococcal Enterotoxin B (SEB) in the presence of IL4 promoted pr oduction of IL10 and IFN gamma predominately by CD8(+) cells. In contr ast, the production of IL4 was almost exclusively confined to the CD4( +) subset. When priming with SEE in vivo before subsequent restimulati on in vitro, a protocol previously shown to induce anergy, up to 80% o f the IL10 and IFN gamma positive cell expressed the CD8 marker. Taken together, these results emphasize the important role of cytokine-prod ucing CD8(+) cells and indicate that CD4(+) and CD8(+) T cells may, in a given situation, produce distinct cytokines.