抄録
The effect and mechanism of the non-ionic detergent, polyethylene sorbitan mono-oleate (Tween 80), on Japanese encephalitis virus (JEV) was examined and following results were obatined.
1. Owing to the action of Tween 80 (0.01v/v%), JEV reduced remarkably in immunogenicity. When Tween 80 was added to the virus fluid not less than 30 days after formalin inactivation, the virus did not lose its immunogenicity and the potency of vaccine was maintained stably.
2. The infectivity of the virus was reduced about 5 logs in four hours and almost completely lost in ten hours after Tween 80 (0.2v/v%) treatment at 30C.
3. Tnterated virus showed infectivity, hemagglutination (HA) and complement fixation (CF) activites in the fraction with a buoyant density of 1.24-1.26g/ml, while non-infectious HA and CF activites were detected with a buoyant density of 1.19g/ml.
On the other hand, Tween 80 treated virus had only non-infectious HA and CF activities in the fraction with a buoyant density of 1.17-1.19g/ml.
4. In gel diffusion test, the untreated virus showed two precipitation bands, while the Tween 80 treated virus presented at least three precipitation bands. Of the three precipitation bands, two were common to those of the untreated virus and one of the two which was situated near the antigen well and considered to be related with infectivity became fainter.
From these results, it is clarified that JEV was disrupted by few molecules of polyethylene oxide which is a component of Tween 80 and viral infectivity and immunogenicity was reduced remarkably, while its HA and CF activities were maintained.
The action of formalin seemed to play a first role and that of Tween 80 is supposed to be suppressed in proportion to the degree of formalin fixation.
