Induction of interferon gamma in mouse spleen cells by culture supernatants of mycoplasma arthritidis.

Factor(s) in the supernatant of cultured mycoplasma arthritidis (MAS) represented potent inducers of interferon (IFN) in cultures of mouse spleen cells. Responding mouse strains included A/J, BALB/c, CBA, C3H, and DBA/2 whereas spleen cells of C57BL/6 and C57BL/10 mice were nonresponders. Interferon production was controlled by the I region of the H-2 locus. Treatment of CBA spleen cells by anti-thy-1 antibody plus C abolished IFN production. A similar effect was seen when CBA spleen cells were freed of macrophages by passage through Sephadex G-10 columns. Pure macrophages themselves, however, were not producing IFN when treated by MAS. Macrophage-depleted CBA spleen cells could be reconstituted to produce IFN by the addition of 2-ME. Interferon induction by CBA spleen cells was independent of lymphoproliferation as evidenced by experiments utilizing mitomycin C. The IFN induced by MAS represented IFN gamma (gamma), since it was acid-labile and neutralized by a specific antiserum.