Cellular source of interferons in the circulation of mice with delayed hypersensitivity.

The cellular origins of type I and type II interferons released into the circulation of mice with delayed hypersensitivity were investigated. We determined the effect of treatment with various immunosuppressive agents, including cyclophosphamide, cycloheximide, antithymocyte serum, and whole-body X-irradiation, on the release of interferons after intravenous injection of specific (old tuberculin) or nonspecific (lipopolysaccharide) stimuli. The results suggest that (i) a heterogeneous population of lymphocytes (T and B cells) produces type II interferon, (ii) type I interferon is produced by a different cell population, and (iii) type II interferon is produced de novo after challenge with old tuberculin of mice sensitized with Mycobacterium bovis BCG.