COMPARATIVE-ANALYSIS OF THE IMMUNOPROTECTIVE ABILITIES OF GLYCOSYLATED AND DEGLYCOSYLATED PARAINFLUENZA VIRUS TYPE-3 SURFACE GLYCOPROTEINS

The role of carbohydrate moieties on the immunoprotective ability of p arainfluenza virus type 3 (PIV-3) haemagglutinin-neuraminidase (HN) an d fusion (F) glycoproteins was tested in hamsters. HN and F proteins w ere purified from detergent-solubilized virus by lentil-lectin affinit y chromatography and deglycosylated by treatment with endoglycosidase F (endo F). Immunization of hamsters with either 1 or 5 mug of mock-tr eated (glycosylated) affinity-purified proteins elicited strong haemag glutination inhibition and neutralizing antibody responses 4 weeks aft er the primary injection. In contrast. titres were significantly lower with endo F-treated (deglycosylated) proteins. However, following the booster doses with at least 5 mug of antigen, glycosylated and deglyc osylated proteins induced comparable antibody titres. There was no sig nificant difference in the ability of the glycosylated or deglycosylat ed proteins to protect either the upper or lower respiratory tracts of immunized hamsters against PIV-3 challenge. These results suggest tha t the carbohydrate moieties of the HN and F proteins are not necessary for eliciting a protective response in hamsters.