R9AP is a common receptor for EBV infection in epithelial cells and B cells.

Epstein-Barr virus (EBV) persistently infects more than 90% of the human population, causing infectious mononucleosis, susceptibility to autoimmune diseases and multiple malignancies of epithelial or B cell-origin. EBV infects epithelial cells and B cells through interaction between viral glycoproteins and different host receptors, but it has remained unknown whether a common receptor mediates infection of its two major host cell targets. Here, we establish R9AP as a crucial EBV receptor for entry into epithelial and B cells. R9AP silencing or knockout, R9AP-derived peptide and R9AP monoclonal antibody each significantly inhibit, whereas R9AP overexpression promotes, EBV uptake into both cell types. R9AP binds directly to the EBV glycoprotein gH/gL complex to initiate gH/gL-gB-mediated membrane fusion. Notably, the interaction of R9AP with gH/gL is inhibited by the highly competitive gH/gL-neutralizing antibody AMMO1, which blocks EBV epithelial and B cell entry. Moreover, R9AP mediates viral and cellular membrane fusion in cooperation with EBV gp42-human leukocyte antigen class II or gH/gL-EPHA2 complexes in B cells or epithelial cells, respectively. We propose R9AP as the crucial common receptor of B cells and epithelial cells and a potential prophylactic and vaccine target for EBV.