Electroporation of Antibodies into Mammalian Cells

The introduction into mammalian cells of antibodies with specificities for endogenous cellular factors permits the functional assessment of such factors in the context of living cells. Antibodies have been successfully introduced into several cell types by various methods, including fine-needle microinjection (1 ), osmotic lysis of pinocytotic vesicles (2 –4 ), liposome-mediated delivery (5 ), and fusion of red cell ghosts loaded with protein (5 –8 ). Each of these techniques has its associated drawbacks: Microinjection is very time-consuming and is inappropriate for transfer of antibodies into large numbers of cells; osmotic lysis of pinocytotic vesicles results in massive cell damage and thus requires very large numbers of cells and long recovery periods (4 ). Red cell ghosts or liposomes require either the use of targeting molecules likely to modify the nature of the target cell membrane (5 ) or the use of potentially hazardous virus to stimulate fusion (6 ,7 ).