High Yield Growth and Purification of Human Parainfluenza Type 3 Virus and Initial Analysis of Viral Structural Proteins

Abstract

Structural proteins from a large-plaque variant (LPV) of human parainfluenza type 3 virus were analyzed by electrophoresis on Laemmli-type polyacrylamide gels. High virus concentrations were obtained by growth in BS-C-1 [African green monkey kidney] cells cultivated on microcarrier beads. Purification of the virus in composite equilibrium gradients of potassium tartrate:glycerol resulted in 25% recovery of input infectivity and a preparation containing < 0.08% of input host cell protein and RNA. Parainfluenza type 3 virus equilibrated at a density of 1.20 g/ml in these gradients. Analysis by polyacrylamide gel electrophoresis of 3H-glucosamine-labeled virus taken from peak gradient fractions revealed 8 or 9 major virion peptides; these range in MW from 17 .times. 103-125 .times. 103 (17K-125K), 2 of which were glycoproteins. The sum of the estimated MW of these peptides, 501.5K-570.5K, does not exceed the estimated genomic potential of other paramyxoviruses.