Copyright © 1997, American Society for Microbiology Direct Interaction between Human Cytomegalovirus

Cellular annexin II has been shown to specifically bind human cytomegalovirus (HCMV) and be a compo-nent of highly purified virions. In this report, we characterize the interaction of annexin II with HCMV. We found that the binding of annexin II to the HCMV envelope occurs partially through the calcium-dependent phospholipid-binding ability of annexin II since some annexin II was dissociated from virions with chelating agents. However, a substantial proportion of virion-associated annexin II was resistant to chelation, which suggested a calcium-independent interaction between annexin II and an HCMV envelope component. The search for a nonphospholipid component to account for this binding led to the discovery that HCMV glyco-protein B (gpUL55) (gB) can physically interact with annexin II. We present three lines of evidence to support the conclusion that HCMV gB can bind host cell annexin II. The betaherpesvirus human cytomegalovirus (HCMV) is a pathogen that is responsible for serious disease and death among immunocompromised populations and is the leading cause of infectious birth defects in the United States (2). As with most other herpesviruses, the mechanism whereby HCMV gains access to the interior of host cells to begin it