Epstein-Barr virus infection of CR2-transfected epithelial cells reveals the presence of MHC class II on the virion.

Epithelial cell lines transfected with the Epstein-Barr virus (EBV) receptor CR2 are susceptible to infection by EBV. Following infection with certain EBV strains we found that these cells became positive for MHC class II. The class II was confirmed as being of viral and not target cell origin by immunostaining with HLA-specific monoclonal antibodies. Electron microscopic immunogold staining confirmed the presence of MHC class II on the surface of the virion. While some MHC class I was also found on the EB virion, other cell surface molecules were absent. Dual color immunofluorescence and confocal microscopy analysis demonstrated colocalization of class II with EBV-encoded structural proteins (MA and VCA) in infected epithelial cells. However, preincubation of EBV with antibodies against either MHC class I or MHC class II failed to affect either EBV binding or EBV infection. The presence of MHC on the surface of the EB virion may be a consequence of the intracellular pathways through which productive virus exits from the cell and may influence the target cell tropism of EBV.