Specificity of a neuraminidase activity of Sendai virus

Selective extraction of haemagglutinin and matrix protein from Sendai virions by employing trifluoperazine as a detergent

Incubation of trifluoperazine, a local anaesthetic, at concentrations higher than the cmc with Sendai virus particles produces the selective solubilization of the haemagglutinin neuraminidase (HN) and matrix (M) proteins. This phenomenon involves aggregation of the Sendai virions and therefore the separation of HN and M from the rest of the particle can be performed by bench centrifugation. The supernatant contains the HN and M proteins and HN, once inserted into liposomes, elicits its own biological activities. Therefore, the method seems suitable for purifying large amounts of HN.

Variation of virulence and other properties among Sendai virus strains

The virulence of five Sendai virus strains (MN, Z, KN, Mol, and Hm) isolated from laboratory rodents was compared, using 3-week-old female Jcl-ICR mice. The virulence of the strains was Mol, MN, KN, Z, and Hm in decreasing order. The 50% lethal dose and 50% lung consolidation inducing dose of the highest virulent strain differed by the order of more than 10(3) and 10(6), respectively, from those of the lowest virulent one. Other properties such as the growth rate in LLC-MK2 cells, neuraminidase activities, and molecular weights of structural proteins also differed among the virus strains. These results indicate that Sendai virus prevailing in laboratory rodents is not homogenous with respect to virulence and some other properties.