Fig. 3.

Inhibitors of PKC, PKA and MEK increase cell sensitivity to lysis by antibody and complement. Carcinoma cells (0·5 × 10⁶) were pretreated with GF109203X, H89 or PD98059, each at 1 µm, or with combinations of these inhibitors, for 30 min at 37°C. Control cells were pretreated with DMSO, 0·2%. Then, the cells were treated with rabbit anti-carcinoma antiserum for 30 min on ice followed by NHS, 60 min at 37°C. Results shown in Figs 3, 1, 2, 3, 4, 5 are each representative of 3 independent experiments and are expressed as the mean percentage of cell lysis (trypan blue inclusion) ± SE.