Growth regulation of the B lymphoma cell line WEHI-231 by anti-immunoglobulin, lipopolysaccharide, and other bacterial products

The growth of WEHI-231, a murine immature B lymphoma cell line, was inhibited by anti-IgM antibodies. The inhibition of proliferation, as measured by [3H]thymidine incorporation, occurred between 16 and 28 hr after addition of anti-IgM. Moreover, the growth arrest was irreversible: cells that were cultured with anti-IgM for 18 hr and then recultured without it failed to recover the ability to proliferate, even though cells treated for up to 30 hr with anti-IgM remained viable, as measured by trypan blue exclusion. Three polyclonal B cell activators obtained from bacteria, lipopolysaccharide (LPS), peptidoglycan from Staphylococcus aureus, and gliding bacterial adjuvant from Cytophaga (GBA), were able to protect WEHI-231 cells from anti-IgM-induced growth arrest. The protection was transient, ending after approximately 56 hr. This transience was shown to be due to desensitization of the cells to the bacterial products. Interestingly, pretreatment of WEHI-231 cells with any of the bacterial products desensitized the cells to all of the bacterial products. The heterologous nature of this desensitization suggests that all three of these bacterial products may act through a common signaling pathway despite their diverse chemical natures.