Maximal concanavalin A-specific agglutinability without loss of density-dependent growth control

Density-inhibited 3T3 mouse fibroblasts were treated for 10 min with nine concentrations of Pronase ranging from 0.25 to 40 mug/ml. Concanavalin A-specific agglutinability increased from control values of about 25% to plateau values of about 80%. None of these Pronase concentrations brought about an increase in cell number within 84 hr. Pronase-treated cells remained responsive to growth stimulation by serum and cortisol. Therefore, the protease-mediated surface change measured by increased concanavalin A-specific agglutinability is not an event sufficient by itself to bring about cell division.