Lymphokines produced by herpesvirus-transformed marmoset monkey lymphoid cell lines. I. Characterization of a constitutively produced interferon

Conditioned media from cultures of marmoset monkey T-lymphoid cell lines transformed by Herpesvirus saimiri or Herpesvirus ateles were found to contain interferon (IFN) activity. Titers between individual cell lines varied by a factor of 100; large amounts (up to 10(5) units/ml, assayed on human cells) were produced in one of the cell lines. IFN production was enhanced by the diterpene tumor promoters, TPA and mezerein, but not by classical T-cell mitogens. The IFN resembles human IFN-gamma by the following criteria: lability at pH 2, stability against 2-mercaptoethanol, cross-species activity, shape of dose-response curves, and molecular weight determined by size-exclusion chromatography (50,000-55,000). Its activity was not inhibited, however, by antiserum against human IFN-gamma or antisera against human IFN-alpha or IFN-beta.