[Characterization and bioactivity of interferon induced by Streptococcus faecalis preparation, TH69]

It was demonstrated that TH69, an lyophylized preparation of streptococcus faecalis TH001 (ATCC No. 31663) induced interferon gamma (IFN gamma) in spleen cell cultures. The IFN activity was found in 8 hrs and reached to the peak of 120-240 U/ml 24-48 hrs after incubation in every concentration of 4, 20, and 100 micrograms/ml of TH69. TH69-induced IFN (TH69-IFN) was produced by T cells assisted by macrophages which were stimulated with TH69, and the activity was neutralized by 80-90% with anti-IFN gamma serum but hardly neutralized with anti-IFN alpha, beta serum. Therefore, TH69-IFN was found to be mostly gamma type. The elution profile of TH69-IFN activity on a column with Toyopearl HW-55S showed that molecular weight of IFN was estimated at 18,000-28,000. Sequential purification on this column of TH69-IFN increased the specific activity to approximately 2.5 X 10(4) U/mg protein (partially purified TH69-IFN: TH69-IFNp). A small amount of TH69-IFNp (5-50 U/ml) augmented NK activity and induced cytotoxic macrophages in vitro. Growth of Meth-A tumor cells exposed to TH69-IFNp of 100 U/ml in vitro declined to 50% and three times injection of TH69-IFN (200 U/50 microliters) into the tumor sites of mice given implants of Meth-A suppressed the tumor growth.