Characterization of interferon induction in mice of resistant and susceptible strains during murine cytomegalovirus infection.

Comparison of the induction of plasma interferon (IFN) by murine cytomegalovirus (MCMV) in BALB/c and CBA mice demonstrated similar kinetics of induction with maximum titres at 6 and 48 h after infection. Although neutralized by antibody to type I (alpha and beta) IFN, the IFN was predominantly acid-labile. The 6 h titre was markedly dependent upon the dose and method of preparation of MCMV and also the strain of mouse used. Higher plasma IFN titres were found in CBA than in BALB/c mice following both intraperitoneal or intravenous infection but this strain variation was not apparent in IFN levels in the spleen and liver. IFN induced by MCMV in CBA and BALB/c mice was equally effective at inhibiting MCMV replication in vitro. Cultured embryo fibroblasts derived from CBA and BALB/c mice produced similar levels of IFN, but it was not detected until 24 h after infection. Use of irradiation chimeras prepared from H-2-compatible high IFN producers (CBA) and low producers (B10.BR) showed that the level of IFN produced at 6 h was dependent upon bone marrow-derived cells.