The Effect of Calcium-Related Factors on the Predominance of IFN-γ or Interleukin-4 in Cultured Mononuclear Cells

Abstract

Certain factors have been studied that might influence whether interferon-γ (IFN-γ) or interleukin-4 (IL-4) will predominate in cultures of peripheral blood mononuclear cells (PBMC). ELISA was used to measure cytokine protein, and PCR was used to quantitate mRNA. It was found that induction with plant lectins produced greater yields of IFN-γ than induction with ionophores, but ionophores alone produced at least equal yields of IL-4 as did lectins. Phorbol myristate acetate (PMA) greatly enhanced IFN yields in the presence of ionophores but had no significant influence on IL-4 production. Calcium-independent cytokine induction using anti-CD28 and PMA resulted in production of both cytokines, whereas depletion of extracellular calcium and magnesium adversely influenced the yield of both IL-4 and IFN-γ Finally, calmidazolium, an inhibitor of calmodulin, had an enhancing effect on IFN-γ yields when phytohemagglutinin (PHA ) was the inducer and an adverse effect when A23187 was the inducer. In contrast, calmidazolium reduced IL-4 yields with both PHA and A23187 induction.