Expression of biologically active and antigenically authentic parainfluenza type 3 virus hemagglutinin-neuraminidase glycoprotein by a recombinant baculovirus.

The hemagglutinin-neuraminidase (HN) gene of human type 3 parainfluenza virus has been inserted into a baculovirus expression vector under the control of the polyhedrin promoter. HN protein produced in insect cells by the recombinant baculovirus appeared to be glycosylated, was transported to the cell surface, and was biologically active. All of the HN epitopes previously mapped functionally to a region(s) involved in neuraminidase and/or hemagglutination activities were conformationally unaltered on the recombinant protein. The HN produced in this system also induced a protective immune response in immunized cotton rats. From these studies we conclude that the HN expressed in insect cells represents a source of authentic HN glycoprotein suitable for structural analysis and immunization.