LACTOFERRIN INHIBITS HERPES-SIMPLEX VIRUS TYPE-1 ADSORPTION TO VERO CELLS

This paper describes the ability of human and bovine lactoferrins (HLf ; BLf), iron-binding proteins belonging to the non-immune defense syst em, to interfere with herpes simplex virus type 1 (HSV-1) infection. S ince lactoferrins are known to bind to heparan sulphate proteoglycans and to low density lipoprotein receptor, which in turn act as binding sites for the initial interaction of HSV-1 with host cells, we tested the effect of these proteins on HSV-1 multiplication in Vero cells. Bo th HLf and BLf are found to be potent inhibitors of HSV-1 infection, t he concentrations required to inhibit the viral cytopathic effect in V ero cells by 50% being 1.41 mu M and 0.12 mu M, respectively. HLf and BLf exerted their activity through the inhibition of adsorption of vir ions to the cells independently of their iron withholding property sho wing similar activity in the apo- and iron-saturated form. The binding of [S-35]methionine-labelled HSV-1 particles to Vero cells was strong ly inhibited when BLf was added during the attachment step. BLf intera cts with both Vero cell surfaces and HSV-1 particles, suggesting that the hindrance of cellular receptors and/or of viral attachment protein s may be involved in its antiviral mechanism.