A murine cell possessing a dominant mutation affecting the regulation of interferon production: characterization by intraspecific hybrids.

Using intraspecific hybrids, we have demonstrated the dominant nature of two phenotypic markers present in a mutant mouse 3T6 cell line, designated 3T6-VrB2. These are, resistance to virus infection (Vr) and semiconstitutive synthesis of interferon (IFsc). Hybrids were formed by polyethylene glycol-mediated fusion between 3T6-VrB2, or its parent 3T6, and 2TG0-13, a triply marked derivative of mouse 3T3 cells. When tested for the Vr marker, 3T6-VrB2 X 2TG0-13 hybrid clones displayed a level of resistance to virus infection which was equal to or greater than that of 3T6-VrB2. Similarly, when tested for the IFsc marker, these hybrid clones were found to possess the capacity to confer an interferon-induced antiviral state in mouse L929 cells upon cocultivation. By comparison, clones derived from 3T6 X 2TG0-13 fusions produced high levels of virus and failed to confer an interferon-induced antiviral state in L929 cells.