A SERUM MANNOSE-BINDING LECTIN MEDIATES COMPLEMENT-DEPENDENT LYSIS OFINFLUENZA VIRUS-INFECTED CELLS

The mechanism of lysis of influenza virus-infected BHK-21 cells by gui nea pig serum (GPS) was investigated. Lysis was shown to involve activ ation of the classical complement pathway and was dependent on the pre sence of a mannose-binding lectin in GPS. FAGS analysis demonstrated C a2+-dependent binding of the lectin to influenza virus-infected, but n ot uninfected, cells. Cells infected with mutant strains of virus lack ing a particular high-mannose oligosaccharide at the tip of the hemagg lutinin molecule showed reduced binding of the lectin and were corresp ondingly less sensitive to lysis by GPS than cells infected with the p arent viruses. The degree or pattern of glycosylation of influenza vir uses thus influences susceptibility to this mechanism of viral clearan ce. By interfering with the infectious process, lectin-dependent compl ement-mediated lysis of infected cells may be an important component o f innate immunity to influenza and other enveloped viruses. (C) 1995 A cademic Press. Inc.