MA 104 cells inoculated with Parainfluenza-3 virus, strain III v2932. The Parainfluenza-2 Virus was grown on monolayer of MA cells. When the cultures showed pronounced c.p.e. virus containing medium was purified from cell fragments by low speed centrifµgation (5000 rpm, 40 min). Virus was pelleted by high speed centrifµgation at 18000 rpm for 2.5 hours in the SW27 rotor for 20 min at + 4 oC, then the supernatant was collected and protein concentration was determined by Lowry method.
Parainfluenza virus, PIV, contains a group of four distinct serotypes of single-stranded RNA viruses belonging to the paramyxovirus family and two subtypes (4a and 4b). Parainfluenza viruse is a negative-sense, single-stranded RNA viruse that possess fusion and hemagglutinin-neuraminidase glycoprotein "spikes" on their surface. The virion varies in size (average diameter between 150 and 300 nm) and shape.