Entry of herpes simplex virus 1 in BJ cells that constitutively express viral glycoprotein D is by endocytosis and results in degradation of the virus.

The BJ cell line which constitutively expresses herpes simplex virus 1 glycoprotein D is resistant to infection with herpes simplex viruses. Analysis of clonal lines indicated that resistance to superinfecting virus correlates with the expression of glycoprotein D. Resistance was not due to a failure of attachment to cells, since the superinfecting virus absorbed to the BJ cells. Electron microscopic studies showed that the virions are juxtaposed to coated pits and are then taken up into endocytic vesicles. The virus particles contained in the vesicles were in various stages of degradation. Viral DNA that reached the nucleus was present in fewer copies per BJ cell than that in the parental BHKtk- cells infected at the same multiplicity. Moreover, unlike the viral DNA in BHKtk- cells which was amplified, that in BJ cells decreased in copy number. The results suggest that the glycoprotein D expressed in the BJ cell line interfered with fusion of the virion envelope with the plasma membrane but not with the adsorption of the virus to cells and that the viral proteins that mediate adsorption to and fusion of membranes appear to be distinct.