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The regulation of growth and differentiation of a murine B cell lymphoma. II. The inhibition of WEHI 231 by anti-immunoglobulin antibodies.

WEHI 231 is a murine B cell lymphoma, which from our previous studies is highly susceptible to a lipopolysaccharide (LPS) induced differentiation signal. In this paper we show that anti-immunoglobulin (Ig) antibody at low concentrations (0.1 micrograms/ml) inhibits cell proliferation and results in cell death. Heterologous sera specific for mu- and kappa-chains, and a monoclonal antibody (E4) developed in our laboratory and specific for mu-chain, profoundly suppressed the growth of WEHI 231 in both soft agar culture and liquid culture. The F(ab')2 fragments were as potent as intact Ig, indicating that neither Fc receptor binding nor complement activation were required for this inhibition of growth. Neither heterologous antibodies that bound to WEHI 231 but not to the Ig receptor, nor a monoclonal antibody that bound to non-Ig cell surface structures (a brain-associated antigen) inhibited the growth of WEHI 231. LPS did not prevent inhibition of growth by anti-Ig antibody, and even when addition of LPS preceded the addition of anti-Ig, profound inhibition occurred. WEHI 231 thus promises to be a convenient tool for investigating the mechanism of signal transmission by the Ig receptor.