Involvement of bovine lactoferrin metal saturation, sialic acid and protein fragments in the inhibition of rotavirus infection

Although the antiviral activity of lactoferrin is one of the major biologic al functions of this iron binding protein, the mechanism of action is still under debate. We have investigated the role of metal binding, of sialic ac id and of tryptic fragments of bovine lactoferrin (bLf) in the activity tow ards rotavirus (intestinal pathogen naked virus) infecting enterocyte-like cells. The antiviral activity of bLf fully saturated with manganese or zinc was slightly decreased compared to that observed for apo- or iron-saturate d bLf. The antiviral activity of differently metal-saturated bLf towards ro tavirus was exerted during and after the virus attachment step. The removal of sialic acid enhanced the antirotavirus activity of bLf. Among all the p eptidic fragments obtained by tryptic digestion of bLf and characterised by advanced mass spectrometric methodologies, a large fragment (86-258) and a small peptide (324-329: YLTTLK) were able to inhibit rotavirus even if at lower extent than undigested bLf. (C) 2001 Elsevier Science B.V. All rights reserved.