Parainfluenza 3--Assay and Growth in Tissue Culture.

Abstract

Various parameters involved in assay and growth of HA1 virus in tissue culture have been examined. Variation in occurrence of cytopathic changes in different cell systems led to development of a new plaque assay technique utilizing hemadsorption properties of the virus. HA1 is adsorbed rapidly to cell monolayers from small volumes (0.1 ml) so that a 1 hr. adsorption period is adequate for routine plaque work. The thermal inactivation curve showed a half-life at 37[degree]C of 10 hrs. Antibody was found in normal human and calf sera and in serum from guinea pigs inoculated intranasally. Growth curves showed that at the end of logarithmic increase (11 hrs.), the concentration of virus in the supernatant fluid was less than 0.1% that in the cells. An average of approximately 50 pfu was produced per cell.