Fig. 3.

Inhibition by anti-FasL fragment antibodies of membrane FasL-induced apoptotic cell death of Fas-expressing Jurkat cells. Wild-type FasL cDNA transfected COS cells were incubated with PBS, control rabbit IgG (1 μg/ml), or affinity-purified rabbit anti-FasL fragment antibodies (1 μg/ml). Jurkat-NU cells were then co-cultured with the COS cells. Cell death was estimated by two-colour fluorescence analysis employing TUNEL staining with FITC and OKT3-PE antibodies. Data shown are representative of three independent experiments. Addition of rabbit anti-FasL fragment antibodies into the Jurkat-NU cell culture without FasL exerted no effects on cell death of the target cells (data not shown).