Incorporation of monoclonal antibodies in living rat pheochromocytoma PC12 cells: Evidence for the intracellular formation of immune complex between the incorporated antibody and a target protein

Abstract

PC12 cells permeabilized with a low concentration of digitonin (5 μM) under controlled conditions were loaded with monoclonal antibodies (MoAb) against the regulatory subunit type II (RII) of cAMP-dependent protein kinase. After digitonin removal from the nutrient medium (DMEM) the loaded cells repaired within 20–30 min and recontinued growth. The inserted MoAb stayed in the repaired cells at least for several hours. MoAb inhibiting the cAMP binding activity of neural RII [Grozdova et al. (1992) Biochem. Int. 27, 811–822; Sveshnikova et al. (1996) Biochem. Int. 39, 1063–1070] were shown to bind the target antigen inside the cells and influence the properties of intracellular protein kinases.