Enhancing effect of alpha-interferon on the C2 synthesis by cultured human monocytes.

C2 synthesis by human peripheral blood monocytes cultured in the presence of human alpha-interferon (IFN-alpha) was studied. IFN-alpha was added in different amounts (1-1000 IU/ml) to the cultures on day 3 and was removed on day 7. As control, mock interferon (m-IFN) was also tested. C2 content of the culture supernatants was measured by immunohaemolytic method. IFN-alpha was found to enhance C2 synthesis in a dose-dependent way. The enhancing effect could be observed even after the removal of IFN-alpha. C2 production by the cultured monocytes was increased by m-IFN as well; the extent of enhancement however, was found to be significantly lower than that induced by the corresponding amount of IFN-alpha. In contrast to the enhancing effect on C2 production, IFN-alpha did not influence total protein synthesis in the cultures, suggesting a selective stimulatory action on the C2 gene.