Studies on the Inactivation Test of Japanese Encephalitis Vaccine : Proposal of a New Method Using Tissue Culture Cells

An improved method for the inactivation test of Japanese encephalitis vaccine is proposed. The principle lies in the detection of residual viruses by inoculating large amount of test samples into the tissue culture cells. The process consists of 3 parts. 1) The introduction of primary cell cultures of hamster kidney. 2) Removal of cytotoxic substances -formalin and thimerosal- from test samples by thorough dialysis. 3) Long period (4 weeks) observations of the primary inoculation bottles and two parallel passages for the appearance of cytopathic effects. The results covered the recovery of routine method and its efficiency is higher than that of the legally determined method of using intracerebral inoculation of mice.