AN INACTIVATED EASTERN EQUINE ENCEPHALOMYELITIS VACCINE PROPAGATED IN CHICK-EMBRYO CELL CULTURE. 1. PRODUCTION AND TESTING
ARMY MEDICAL RESEARCH INST OF INFECTIOUS DISEASES FORT DETRICK MD
Pagination or Media Count:
A formalin-inactivated Eastern equine encephalomyelitis vaccine was prepared from the PE-6 strain virus, propagated in primary chick-embryo cell cultures maintained with Medium 199 containing 0.25 human serum albumin. To effect an increase in antigenic mass per unit volume of fluid harvest, we used the pooled fluids from the first tissue-culture passage as maintenance medium for two additional passages. A formalin concentration of 12,000 0.05 at 37C was used for inactivation of the virus suspension. Tests on the in-process and final vaccine documented the safety and sterlity. Tests of potency on the final lyophilized product in hamsters and guinea pigs yielded ED50 values of 0.009 ml and 0.012 ml, respectively. Recent assays have revealed no change in potency after storage of the final product for 17 months at -20C.
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