Immune interferon production by TH69, a lyophilized preparation of Streptococcus faecalis, in murine spleen cell cultures

In mouse spleen cell cultures, TH69, a live Streptococcus faecalis (ATCC 31663) preparation, at a concentration of 20 micrograms/ml induced immune interferon (IFN gamma) with molecular weight ranging from 20,000 to 40,000 daltons together with a small amount of IFN alpha/beta. By using nonsensitized mouse spleen cells, the fact that both T-cells and macrophages are required for this IFN production was established. When these spleen cells were obtained from mice sensitized 12 days earlier with 4 mg of TH69, twice as much IFN was produced than in cells obtained from nonsensitized mice. This increase was explained by the presence of both sensitized macrophages and T-cells in a reconstitution experiment.