High-level IL-10 production by monoclonal antibody-stimulated human T cells

We investigated interleukin-10 (IL-10) production in freshly isolated mononuclear cells and purified T cells in response to stimulation with monoclonal antibodies (mAb) recognizing CD3, CD2 and CD28, or with the bacterial products Staphylococcus aureus cells (SAC), staphylococcal enterotoxin (SEA) and lipopolysaccharide (LPS). IL-10 production was compared with that of IL-2, IL-4 and interferon-gamma (IFN-gamma). Similar to the other cytokines, in peripheral blood mononuclear cells (PBMC) from adult donors the highest IL-10 levels were produced in response to CD2 plus CD28 stimulation, within 72-96 hr of stimulation. Levels of IL-10 in response to CD2 plus CD28 stimulation (1.9 +/- 1 ng/ml) exceeded those in response to SEA (0.25 +/- 0.16 ng/ml), SAC (0.43 +/- 0.42 ng/ml), or LPS (0.19 +/- 0.14 ng/ml) stimulation. With adult purified T cells, high levels of IL-10 and IL-4 were measured following CD3 plus CD28 stimulation, and the amounts of both T-helper type-2 (Th2) cytokines decreased following the addition of phorbol myristate acetate (PMA), whereas the synthesis of the Th1 cytokines IL-2 and IFN-gamma was enhanced. When PBMC were stimulated with a CD3 mAb and different other cytokines were added, strong enhancement of IL-10 production was seen upon the addition of IL-2, IL-4, IL-7, IL-12 and IFN-gamma, whereas inhibition was found with transforming growth factor-beta 1 (TGF-beta 1). These data illustrate that in freshly isolated PBMC large amounts of IL-10 can be induced rapidly by appropriate mAb stimulation, and that even in freshly isolated cells IL-4 and IL-10 show signs of parallel regulation.