FIG. 9.

High-concentration anti-CD3 MAb stimulates Erk activation in Lck-negative Jurkat. (A) JCaM1 and JCaM1/Lck T cells were stimulated by CD3 cross-linking for 2 min at 37°C with the indicated concentration of purified UCHT1 MAb. Erk and MEK-1 phosphorylation in WCLs were measured as in Fig. 1. (B) As for panel A, except that 20 μg of UCHT1 per ml was used and the time of stimulation was varied between 0 and 16 min.