Studies of antibody affinity in plasmacytoma-bearing mice: Evidence for a maturational defect of B lymphocytes

The antibody response of plasmacytoma-bearing mice (PC-mice) is severely reduced. In order to understand the nature of the effect of the tumor on the cells making antibody, quantitative and qualitative studies of the humoral response of PC-mice were undertaken. In these studies, the affinity of the antibody produced by tumor-bearing and normal mice was compared to determine whether the small amount of antibody produced by PC-mice is the product of a normal or an altered population of B cells. Antibody to TNP-Ficoll made by PC-mice 3 days after immunization was less heterogeneous and of an affinity lower than that of antibody made by normal mice. However, at 7 days, the antibody made by PC- and normal mice did not differ significantly. These data suggest that, prior to antigenic stimulation, the B cells of PC-mice are relatively immature, reflecting a possible retardation in the generation and turnover of B lymphocytes. The process of antigen-driven selection of high-affinity antibody-producing cells, however, appears to function normally in PC-mice. These studies, then, reveal a qualitative as well as quantitative defect in the primary humoral response of PC-mice which may reflect an abnormality in the development and differentiation of B cells in these mice.