Formalin-Inactivated Venezuelan Equine Encephalomyelitis (Trinidad Strain) Vaccine Produced in Rolling-Bottle Cultures of Chicken Embryo Cells,
ARMY MEDICAL RESEARCH INST OF INFECTIOUS DISEASES FORT DETRICK MD
Pagination or Media Count:
Formalin-inactivated Venezuelan equine encephalomyelitis vaccine was prepared from virus grown in rolling-bottle cultures of chicken embryo cells. Trinidad strain virus was propagated in these cultures with a maintenance medium consisting of serum-free medium 199 containing 0.25 human serum albumin USP and antibiotics. Manipulation of multiplicity of inoculum 0.06 to 0.00006 and maintenance medium volume 100 to 300 ml resulted in high-titered virus yields and only moderate cell destruction when fluids from infected cultures were harvested at 18 to 24 hr. The virus was inactivated at 37 C by 0.05 Formalin within 8 to 10 hr and with 0.1 Formalin within 6 to 8 hr. Single dose, antigen extinction tests in mice performed with 30 small-scale vaccine lots showed excellent potency at either Formalin concentration with inactivation periods ranging from 24 to 96 hr.