Kinetics of PKA activity changes in BL cells treated by 38.13 MoAb. CD77⁺ Ramos and Daudi cells and CD77⁻ Namalwa cells were cultured with 38.13 anti-CD77 MoAb, and PKA activities were measured. Initial PKA activity was 3,100 pmol/min/mg of protein for Ramos, 1,975 for Daudi, and 4,500 for Namalwa cells.