INCORPORATION OF MONOCLONAL-ANTIBODIES IN LIVING RAT PHEOCHROMOCYTOMAPC12 CELLS - EVIDENCE FOR THE INTRACELLULAR FORMATION OF IMMUNE-COMPLEX BETWEEN THE INCORPORATED ANTIBODY AND A TARGET PROTEIN

PC12 cells permeabilized with a low concentration of digitonin (5 mu M ) under controlled conditions were loaded with monoclonal antibodies ( MoAb) against the regulatory subunit type II (RII) of cAMP-dependent p rotein kinase. After digitonin removal from the nutrient medium (DMEM) the loaded cells repaired within 20-30 min and recontinued growth. Th e inserted MoAb stayed in the repaired cells at least for several hour s. MoAb inhibiting the cAMP binding activity of neural RII [Grozdova e t al, (1992) Biochem, Int, 27, 811-822; Sveshnikova et al. (1996) Bioc hem, Int, 39, 1063-1070] were shown to bind the target antigen inside the cells and influence the properties of intracellular protein kinase s, (C) 1998 Federation of European Biochemical Societies.