Protection of adult BALB/c mice against MOPC 315 myeloma by neonatal administration of monoclonal anti-idiotypic antibody to MOPC 315 IgA.

Ascitic fluid containing monoclonal anti-idiotypic antibody (AIA) to MOPC 315 IgA was administered to newborn BALB/c mice, and the mice were challenged in adulthood with IgA-producing MOPC 315 myeloma cells. Administration of AIA D10 (a hybrid molecule containing IgG1 and IgG2a heavy chains), G3 (IgG2b), and A2 (IgG1), all of which reacted with MOPC 315 cells in a cell-binding radioimmunoassay, prolonged survival and reduced the percentage of IgA-producing spleen fragments derived from mice challenged with MOPC 315 myeloma cells, but not with cells of a related IgA-producing myeloma, MOPC 460. Reduction in the percentage of IgA-producing spleen fragments was prevented by treatment of spleen cells prior to culture with anti-Thy 1.2 antibody and complement. Administration of AIA F1 (IgG2a), which did not react with MOPC 315 cells in vitro, or of an antibody with no AIA activity did not produce a similar protection. These results suggest that administration of AIA to MOPC 315 IgA to neonatal BALB/c mice induces idiotype-specific T-lymphocytes that protect these mice against a challenge with MOPC 315 myeloma cells in adulthood.