Anti-immunoglobulin Antibodies Induce Apoptosis in Immature B Cell Lymphomas

WEHI-231 and CH31 are phenotypically immature sIgM+ murine B cell lymphomas whose growth is inhibited by anti-immunoglobulin (Ig) antibodies. These lines have therefore been used as models for studying the role of surface Ig receptors in the induction of B cell tolerance. We show here that anti-mu antibodies induce DNA cleavage into oligonucleosomal fragments characteristic of programmed cell death (apoptosis) in both cell lines, although WEHI-231 cells are less susceptible than CH31. This effect was reversed by lipopolysaccharide, in agreement with the known effects of lipopolysaccharide on anti-Ig-induced growth inhibition. These results therefore indicate that these lymphomas afford a potentially interesting model to study the mechanisms of programmed cell death induced by ligation of the antigen receptors on normal B cells.