Alteration of cell-surface antigenicity of the mouse plasmacytoma. II. Lack of correlation between synthesis of myeloma protein and alteration of surface antigen.

The correlation between the changes of immunoglobulin synthesis and the surface antigenicity was analyzed by cytotoxicity and quantitative antibody-absorption tests with the cells of immunoglobulin-producing and nonproducing mouse plasmacytoma. IgA-synthesizing BLAB/c plasmacytoma 58-8 and the non-IgA-synthesizing variant of the 58-8 (nonproducer) were killed with rabbit anti-58-8 plasmacytoma cell antiserum, C3H/He anti-BALB/c spleen cell antiserum, and (C57BL/6 X DBA/2)F1 anti-BALB/c plasmacytoma cell MOPC-31C antiserum plus complement, only when the cells were pretreated with pronase. Quantitative absorption tests revealed that the nonproducer, 58-8 had the same amount of plasmacytoma antigen of 58-8 and PC.1 antigen, and a greater amount of H-2d antigen, as did producer 58-8. The same analysis was carried out for the C3H mouse plasmacytoma X5563, which has an M-component of IgG2a. The nonproducer X5563 had a greater amount of H-2k antigen and a smaller amount of the plasmacytoma antigen of X5563 than did the producer X5563. No detectable PC.1 antigen was observed at surfaces of the producer and the nonproducer X5563 cells.