| Human cytomegalovirus (HCMV) can cause severe sight-threatening and/or life-threatening disease, particularly in immunocompromised hosts. A 92.5 kDa cell membrane protein was identified as a putative receptor for HCMV envelope glycoprotein H (gH) that mediates virus/cell fusion. Four steps were taken to identify this protein and verify its function: (1) identification of a fusion-negative cell line, (2) isolation of cDNA clones that encode the receptor, (3) isolation of receptor peptides, and (4) transfection of fusion-negative cells with receptor cDNA.;Identification of fusion-incompetent cells was performed using immunofluorescence (IFA) and immunoblot assays employing anti-idiotypic antibodies that mimic gH, and a fusion assay with R;Clones containing cDNA of the receptor were identified from HEL ;Transfection of fusion-incompetent MOLT-4 cells with a eucaryotic expression vector containing the partial receptor cDNA rendered these cells susceptible to HCMV/cell fusion. In addition, fusion blocking studies using synthetic receptor peptides indicated the HCMV binding domain is contained within an 18 amino acid segment from the extracellular region in the middle of the protein. This work not only identifies a novel cell membrane protein, but provides additional evidence for the role of the 92.5 kDa cell membrane protein in HCMV/cell fusion. |
