ANTIGEN-STIMULATED IL-4, IL-13 AND IFN-GAMMA PRODUCTION BY HUMAN T-CELLS AT A SINGLE-CELL LEVEL

To understand the intricate balance and the coordinate expression of t he Th1 and Th2 cytokines following a natural mode of T cell triggering , antigen-stimulated IL-4, IL-13 and IFN-gamma production was studied in primary peripheral blood mononuclear cell cultures at a single-cell level. Cells from filariasis patients who respond to parasite antigen by producing not only IFN-gamma but also IL-4 and IL-13 were stimulat ed with Brugia malayi adult worm antigen and analyzed for co-expressio n of cytokines by intracellular staining. IL-4 and IL-13 were frequent ly co-expressed (54% of IL-4(+) cells stained for IL-13 and 29% of IL- 13(+) cells expressed IL-4 at all time points), whereas IFN-gamma expr ession was totally segregated from both IL-4 and IL-13. These data ind icate that in human peripheral T cells the co-expression of the domina nt Th1 and Th2 cytokines within a single cell is a rare event and that IL-13 is clearly more frequently associated with a Th2 than a Th1 typ e response in primary T cell cultures.