Identification of a Chemokine Receptor Encoded by Human Cytomegalovirus as a Cofactor for HIV-1 Entry

Abstract
The human cytomegalovirus encodes a β-chemokine receptor (US28) that is distantly related to the human chemokine receptors CCR5 and CXCR4, which also serve as cofactors for the entry into cells of human immunodeficiency virus–type 1 (HIV-1). Like CCR5, US28 allowed infection of CD4-positive human cell lines by primary isolates of HIV-1 and HIV-2, as well as fusion of these cell lines with cells expressing the viral envelope proteins. In addition, US28 mediated infection by cell line–adapted HIV-1 for which CXCR4 was an entry cofactor.