Cellular handling of a monoclonal anti-idiotypic antibody in IgA-producing MOPC 315 mouse myeloma cells.

MOPC 315 mouse myeloma cells which produce an IgA (alpha, lambda 2) with dinitrophenol (DNP)-binding capacity were incubated with a [125I]-labeled monoclonal anti-idiotypic antibody (AIA) (D10) to MOPC 315 IgA. AIA D10 bound specifically to the surface of MOPC 315 cells (binding constant 3.0 X 10(7)/mole) but not to cells of a derivative clone which did not produce IgA. Following binding, D10 was taken up intracellularly and localized in a subcellular fraction which sedimented in a Percoll gradient on the light side of the main lysosomal peak. These results indicate that monoclonal AIA to MOPC 315 IgA is selectively bound and internalized by MOPC 315 myeloma cells.