An immunosuppressive lipoprotein fraction from TEPC-183 bearing mice.

Lipoprotein (LP) fractions prepared from sera of normal and plasmacytoma (TEPC-183) bearing mice, were compared with respect to their effect on the in vitro anti-2,4,6-trinitrophenyl plaque forming cell response. Very low density lipoprotein (VLDL) and low density lipoprotein (LDL) fractions of sera from the plasmacytoma bearing mice contained immunosuppressive activity that was absent in VLDL and LDL fractions of normal serum LP fractions. The suppressive activity did not correlate with cholesterol or triglyceride content. Crossed-immunoelectrophoresis and polyacrylamide gel electrophoresis revealed components of the suppressive VLDL and LDL fractions which were not present in normal serum LP fractions, suggesting a modification of serum LPs by the plasmacytoma.