Modification by adoptive humoral immunity of murine cytomegalovirus infection

The effects of specific antiviral antibody on several aspects of infection with murine cytomegalovirus (CMV) were examined. Administration of immune serum 24 hr before subcutaneous inoculation of 10(5) plaque-forming units of murine CMV prevented detectable viral replication in the tissues of 92% of animals. Protection was associated with the immune globulin fraction and not with normal serum or heterologous antiviral serum. However, the development of latent murine CMV infection was not prevented by prior administration of antibody since immunosuppression with antilymphocyte serum and cortisone 16 weeks later unmasked dormant virus in 17 of 20 animals. In normal animals murine CMV-immune serum administered six days after acute virus infection had been initiated did not influence the outcome; however, in immunosuppressed mice, virus dissemination during acute infection was substantially reduced by specific antibody. These results demonstrate a significant effect of humoral immunity on the course of experimental CMV infection.