Intracellular glycosylation of influenza hemagglutinin: the effect of glucosamine.

The intracellular glycosylation of influenza virus hemagglutinin has been studied in calf kidney primary cultures infected with influenza virus A/NWS (H0N1). Intermediate glycosylated forms were obtained by the addition of glucosamine to the culture medium; they were characterized after [35S]-methionine labelling by their precursor relationship, by immunoprecipitation and peptide mapping. The underglycosylated hemagglutinins were distributed in classes of discrete molecular weight indicating that glycosylation occurred in a stepwise manner. A total of 8 different bands, suggesting 7 glycosylation sites, was obtained under conditions of both complete and incomplete glycosylation.