Functional changes in murine macrophages infected with cytomegalovirus relate to H-2-determined sensitivity to infection

Peritoneal macrophages were infected with murine cytomegalovirus in vitro, and indices of infection and macrophage function were monitored over 4 days. When the cells were assessed for the expression of viral antigen or for cytopathic effects, infection was found to be solely determined by the H-2 phenotype. Less than 10% of the macrophages from resistant H-2k strains were affected, whereas 90% of H-2d cells and approximately 80% of H-2b and H-2a cells became infected. Similar trends were demonstrable by the measurement of viral DNA. In H-2a cells (B10.A), Dd conferred sensitivity despite the resistant K and class II phenotype. The findings suggest a critical association between the class I antigens and an early stage in the infectious process. Indices of infection were paralleled by a loss of Fc receptor expression and optimal colloidal gold uptake, whereas most cells remained trypan blue negative, retained dehydrogenase and acid phosphatase activities, and did not release infectious virus during the period of study. This is consistent with a role for macrophages in the persistence of cytomegalovirus in the host.