Contributions of the Four Essential Entry Glycoproteins to HSV-1 Tropism and the Selection of Entry Routes

Herpes simplex viruses (HSV-1 and HSV-2) contain up to 16 different proteins in their envelopes. Four of these, glycoproteins gB, gD, gH, and gL, are termed essential with regard to entry, whereas the rest are typically referred to as nonessential based on the entry phenotypes of the respective single genetic deletions.