Gamma-irradiated Venezuelan equine encephalitis vaccines.
The efficacy of Formalin-inactivated Venezuelan equine encephalitis (VEE) vaccine has been reported to be low for man. Although a live VEE vaccine has been shown to be highly effective for the protection of laboratory workers, local and systemic reactions have occurred in approximately 20% of inoculated individuals. Therefore, studies were initiated in an attempt to produce an inactivated vaccine of high potency with low toxicity. Inactivated VEE vaccines were prepared by exposing virus suspensions to 8 x 10(6) or 10 x 10(6) r of gamma radiation. Irradiated VEE vaccines prepared from virus suspensions produced in Maitland-type chick embryo (MTCE) cell cultures and in monolayer cultures of human diploid strain WI-38 cells were highly immunogenic for mice and guinea pigs. Guinea pigs vaccinated with a series of three inoculations of vaccine (MTCE) survived challenge with at least 10(8.4) mouse intracerebral 50% lethal doses of VEE virus. Irradiated vaccines induced high levels of serum-neutralizing and hemagglutinin-inhibiting antibodies in guinea pigs and rabbits. These findings suggest that ionizing radiation may be effective in the preparation of an inactivated VEE vaccine.
D000818:Animals; D000906:Antibodies / Q000032:analysis; D001681:Biological Assay; D002460:Cell Line; D002642:Chick Embryo; D003036:Cobalt Isotopes; D004660:Encephalitis / Q000517:prevention & control; D004668:Encephalitis Viruses / Q000276:immunology*; D004683:Encephalomyelitis, Equine; D005347:Fibroblasts; D005557:Formaldehyde; D006168:Guinea Pigs; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D008168:Lung; D051379:Mice; D009500:Neutralization Tests; D011817:Rabbits; D011830:Radiation Effects; D014687:Venezuela; D014765:Viral Vaccines / Q000494:pharmacology / Q000528:radiation effects*
D000906:Antibodies; D003036:Cobalt Isotopes; D014765:Viral Vaccines; D005557:Formaldehyde