FIG. 1.
Th1-type cytokine functional characterization of CD4+ T cells. Staining for intracellular IFN-γ, TNF-α, TNF-β, and IL-2 was conducted following stimulation with SEB or with PMA and A23187 (a calcium ionophore) for 6 or 18 h of in vitro culture of PBMCs. Brefeldin A was added for the last 5 h to inhibit protein secretion. TNF-β was only detected after 18 h of culture and only at a low frequency. Cells were gated on the CD4hi population for SEB stimulation and controls or on all lymphocytes for PMA stimulation.