Immunoregulatory Action of Type I Interferon in the Mouse*

The effect of type I interferon production on immunity to the interferon-inducing virus was examined using the Newcastle disease virus [NDV]-mouse model and comparing If-1h and If-1l animals. The degree of cell-mediated immunity, as measured by delayed hypersensitivity [DH] to NDV, was influenced by the levels of interferon produced. Anti-interferon globulin given immediately after immunization decreased sensitization to NDV, whereas additional, exogenous, interferon, given to low interferon producers, stimulated sensitization to NDV. The alleles at the If-1 locus influenced the extent of DH to NDV, in that If-1h mice developed much stronger DH than did If-1l mice. However, results from recombinant inbred strains, F2 and backcross generations showed that for interferon production to stimulate DH to NDV, other genes, present in the C57BL/6 background but as yet not characterized, are required. Thus DH to NDV is determined on the one hand by the alleles at If-1, influencing interferon production, and on the other hand by a combination of several genes affecting the interaction of interferon with cells of the immune system.