Herpes simplex virus type 1 glycoprotein H binds to alpha v beta 3 integrins

Glycoprotein H (gH) homologues are found in all members of the herpes virus family, and gH is one of the virion envelope glycoproteins that is essential for virus entry. In this study, a recombinant soluble form of Herpes simplex virus type 1 (HSV-1) gH, in which the ectodomain is fused to the Fc-binding region of IgG, has been generated. This was expressed in mammalian cells together with gL and the resulting gHFc-gL heterodimer was purified using Protein A Sepharose. Low-affinity cell binding assays showed that gHFc-gL bound specifically to Vero cells and mutation of a potential integrin-binding motif, Arg-Gly-Asp (RGD), in gH abolished binding. CHO cells failed to bind in this assay. However, CHO cells expressing the human alphavbeta3 integrin bound efficiently to gHFc-gL, suggesting that HSV-1 gH can bind to cells using alphavbeta3 integrins and that this binding is mediated by the RGD motif in the gH ectodomain.