Production of interferon in human cell cultures by a new, potent viral inducer

A new discovered double-stranded RNA inducer of interferon, bluetongue virus (BTV), stimulates the production of large amounts of interferon in animals as well as in many types of mammalian cell cultures, including human leukocytes, and continuous cell lines. The exceptional pH lability of BTV and its lack of pathogenicity for man further recommend its use as an interferon inducer. Among several human cell lines tested, the most efficient producer of interferon was a continuous cell line designated HT-1376, derived from a bladder carcinoma. With infectious BTV as the inducer, the HT-1376 line produced more interferon per cell than did leukocytes; interferon yields ranged from 10,000 to 60,000 units per ml of crude, unconcentrated supernatant fluid. Noninfectious BTV, inactivated by ultraviolet irradiation, was as effective as infectious virions. The interferon produced in HT-1376 cells has physicochemical and antigenic properties resembling those of fibroblast interferon produced in diploid cells.