Suppression of In Vivo Growth of Mouse Myelomas by Purified Rabbit Antibodies Against Mouse Myeloma Cells

Summary

Tested for their effects on in vivo growth of different myeloma lines were antibodies against myeloma cell-surface antigens, prepared by the immunization of rabbits with BALB/c mouse myeloma cells- either MOPC104E (an IgM-producing line) or MOPC-21 (an IgG-producing line)- and purified by passage through mice. Anti-MOPC-I04E-cell antibodies most strongly inhibited growth of homologous MOPC-I04E and moderately suppressed growth of myelomas Adj-PC-5 (an IgG-producing line) and Adj-PC-22A (an IgA-producing line), as expected from their pattern of in vitro cytotoxic reactivity. However, they enhanced growth of MOPC-21 cells, which were only weakly sensitive to the in vitro cytotoxicity of anti-MOPC104E- cell antibodies. Anti-MOPC-21-cell antibodies suppressed growth of MOPC-I04E and myeloma Adj-PC-22A but did not inhibit growth of a lymphoma. Although moderately Cytotoxic in vitro for the rapidly growing, homologous MOPC-21 cells, they could not suppress growth of the myeloma in vivo under the injection schedule used to suppress growth of the slower growing MOPC-I04E and Adj-PC-22A myelomas.