抄録
Studies were made for the improvement of the potency test of Japanese B encephalitis vaccine. Results obtained are summarized in the following :
1. The new potency test proposed is to use 60 young mice 3-4 weeks of age. They are divided into 2 groups of one receiving the intraperitoneal inoculation of a test vaccine in a dose of 0.1 ml on two occasions with an interval of 4 days and the other to serve as control. Eight days after inoculation, animals of both groups are challenged with an intraperitoneal inoculation of the test virus with a virulence of 3, 000 LD50 in 0.2 ml of the inoculum and then the mortality rate is compared between the two groups.
2. The use of this method made it easy to perform the potency test of Japanese B encephalitis vaccine.
3. The use of this method made it possible to determine the expiration date of the same vaccine.
4. The use of this method facilitated the assay of the quality of this vaccine.
5. This method was adopted in 1953 as the routine procedure of the potency test of Japnese B encephlitis vaccine at the National Veterinary Assay Laboratory.
