CELLULAR HANDLING OF A MONOCLONAL ANTI-IDIOTYPIC ANTIBODY IN IGA-PRODUCING MOPC-315 MOUSE MYELOMA CELLS

Abstract

MOPC 315 mouse myeloma cells which produce an IgA (a, .lambda.2) with dinitrophenol(DNP)-binding capacity were incubated with a [125I]-labeled monoclonal antiidiotypic antibody (AIA) to MOPC 315 IgA. AIA D10 bound specifically to the surface of MOPC 315 cells (binding constant 3.0 .times. 107/mol) 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. Monoclonal AIA to MOPC 315 IgA is selectively bound and internalized by MOPC 315 myeloma cells. [Application of this research to targeting antitumor agents to myelomas was noted].