Type I and II Interferons and Migration Inhibitory Factor: Production in Mycobacterium Bovis BCG-infected Mice Desensitized with Old Tuberculin or Lipopolysaccharide

Mice with delayed hypersensitivity induced by infection with Mycobacterium bovis strain BCG were desensitized by a single large dose of specific antigen (old tuberculin, OT) or a nonspecific interferon stimulus (bacterial lipopolysaccharide, LPS). Subsequent challenge of the desensitized animals revealed only a homologous hyporeactivity, that is, mice desensitized with OT showed decreased type II and migration inhibitory factor (MIF) responses to the specific antigen, which were unaffected by desensitization with LPS. Conversely, mice desensitized with LPS showed a decreased type I interferon and MIF response to LPS, which was unaffected by desensitization with OT. These results suggest that type I interferon and its accompanying low-titered MIF activity are produced by cell populations different from those that produce type II interferon and its accompanying high-titered MIF activity.