Regulatory effects of IgG-BF on hybridoma B cells. molecular characterization of variant cell lines.

Immunoglobulin G-binding factors (IgG-BF) produced by mouse T cells or hybridoma T cells (T2D4) were used to manipulate in vitro mouse hybridoma B cells. Both IgG production by, and proliferation of, these cells was inhibited by IgG-BF, or during co-cultures with IgG-BF-producing T2D4 cells. Thus, treatment of tumor B cells, besides its potential therapeutic use, represents an invaluable model for studying the regulation of Ig production by IgG-BF at a molecular level. To further analyze the molecular events induced by IgG-BF in B cell hybridomas, a set of variant clones of a hybridoma cell line (UN2) was isolated and variants were characterized for their Ig production and their Fc gamma R expression.