Cytofluorimetric analysis of CD95L induction during gp120-apoptosis. Clone 103 (Th1) and clone 2/46 (Th2) were analyzed for CD95 and CD95L expression (shaded histograms) with an indirect immunofluorescence 1 hour after treatment for induction of gp120-apoptosis. Cells were incubated with fluorescein-conjugated anti-CD95 MoAb UB2 or biotinylated anti-CD95L MoAb 4A5 followed by Streptavidin-PE; the percentage of positive cells is indicated. Negative controls (empty histograms) were cells stained with fluorescein-conjugated or biotinylated isotype-matched control MoAb, respectively. (A) Cells treated with anti-TCR MoAb only; (B) cells sensitized to gp120 apoptosis (gp120/anti-gp120/anti-TCR); (C) cells stimulated with PMA/ionophore.