Fig. 5.
F(ab')2 fragments are as efficient as intravenous immunoglobulin (IVIg) to interact with phytohaemagglutinin (PHA) and inhibit Jurkat T cell activation. (a) The PHA reactivity of equimolar amounts of F(ab')2 fragments (33 µg/ml) was compared to that of IVIg (50 µg/ml) in enzyme-linked immunosorbent assay (ELISA). Results [± standard deviation (s.d.)] are representative of four separate experiments. n.s.: not significant (Mann–Whitney U-test). (b) Jurkat T cells were incubated in the presence of PHA and equimolar amounts of IVIg (5 mg/ml) or F(ab')2 fragments (3·3 mg/ml) for 24 h prior to evaluation of interleukin (IL)-2 secretion by ELISA. Results shown are the mean (± s.d.) of four independent experiments. ***P < 0·001 (Kruskal–Wallis with Dunn's post-test).