Human cytomegalovirus is a species of the Cytomegalovirus genus of viruses, which in turn is a member of the viral family known as Herpesviridae or herpesviruses. It is typically abbreviated as HCMV or, commonly but more ambiguously, as CMV. CMV Virus Envelope Glycoportein B (CMV-GB) can be cleaved into glycoprotein GP55. Envelope glycoprotein that plays a role in host cell entry, cell to-cell virus transmission, and fusion of infected cells. CMV-GB may be involved in the initial attachment via binding to heparan sulfate together with the gM/gN complex that binds heparin with higher affinity. Furthermore, CMV-GB can interact with host integrin ITGB1, PDGFRA and EGFR that likely serve as postattachment entry receptors. Also, CMV-GB participates in the fusion of viral and cellular membranes leading to virus entry into the host cell. Membrane fusion is mediated by the fusion machinery composed at least of gB and the heterodimer gH/gL.