Integrating signals from IFN-γ and IL-4 by B cells: Positive and negative effects on CD40 ligand-induced proliferation, survival, and division-linked isotype switching to IgG1, IgE, and IgG2a

Abstract

IL-4 and IFN-γ each have potent effects on B cell responses as well as strong mutual antagonism. Here we have examined the quantitative effects of these cytokines on CD40 ligand-induced B cell proliferation, cell survival, and division-linked isotype switching. Both IL-4 (strongly) and IFN-γ (weakly) enhanced the number of B cells found in culture by reducing the average time cells take to enter the first division cycle and by promoting B cell survival. When added in combination, the net effect of IL-4 and IFN-γ on time to division and survival was a response intermediate between that of the two cytokines alone, indicating a partial antagonism of IL-4 by IFN-γ. By modulating both time to div..