Cytomegalovirus Production by Infected Astrocytes Correlates with Transforming Growth Factor‐β Release

Abstract

Cytomegalovirus (CMV) encephalitis is well documented in immunosuppressed persons, but its pathogenesis has received little investigative attention. The examination of brain tissue from 2 patients with acquired immunodeficiency syndrome who had CMV encephalitis showed colocalization of CMV inclusions and transforming growth factor (TGF)-beta in cells that contained astrocyte-specific glial filaments. To investigate the relationship between CMV and TGF-beta in the brain, an ex vivo murine model of CMV-infected astrocytes was established. Cultures of primary murine (strain FVB/N) astrocytes inoculated with murine (Smith strain) CMV expressed, over time, increasing amounts of infectious CMV in parallel with increasing levels of TGF-beta mRNA and peptide. Astrocyte release of CMV declined in the presence of antibody to TGF-beta and increased substantially after the addition of exogenous TGF-beta. These findings suggest that CMV infection of astrocytes induces the production of TGF-beta, which in turn enhances productive CMV expression.