Parainfluenza Virus Surface Projections: Glycoproteins with Haemagglutinin and Neuraminidase Activities

Abstract

The parainfluenza virus SV5 has been found to contain six proteins with mol. wts ranging from about 41,000 to 76,000 (Caliguiri, Klenk & Choppin, 1969; Mountcastle, Compans & Choppin, 1971). The nucleocapsid of the virus particle is composed of a single polypeptide chain with a mol. wt. of about 61,000 (Mountcastle et al. 1970); the other five proteins are presumably associated with the virus envelope. Two of the proteins are covalently linked to carbohydrate (Klenk, Caliguiri & Choppin, 1970). We report here that these glycoproteins comprise the spikes or projections on the surface of the SV5 virus particle. The w3 strain of SV5 (Choppin, 1964) was grown in MDBK cells (Choppin, 1969) in reinforced Eagle's medium (Bablanian, Eggers & Tamm, 1965) with 2% calf serum. Cells were inoculated at a multiplicity of about 10 p.f.u./cell.