Demonstration of Immune Response to Foot-and-Mouth Disease Vaccine In Protection Test in Young Adult Mice

Abstract

Current techniques for potency testing of foot-and-mouth disease vaccines requiring the use of a number of cattle are so expensive and difficult as to be almost impractical. Studies for a substitute test using small laboratory animals are thus warranted and this report describes experiments performed to evaluate the protection produced in young adult mice by foot-and-mouth disease vaccines prepared from virus of different sources and to determine if the protection afforded was type specific. Vaccines of the Frenkel type using viruses of the 3 strains (i.e., A, O, and C) of foot-and-mcuth disease were inoculated subcutaneously in mice 3 to 6 weeks of age weighing 9-13g at time of vaccination. Foot-and-mouth disease viruses adapted to growth in adult mice were used for challenge. The mice were observed for a period of 15 days, titration end-points were calculated by the method of Reed and Muench and the difference between end-points obtained in vaccinated and in control mice provided an indication of degree of protection produced. The experimental results presented in table form show that foot-and-mouth disease vaccines induce immunity in young adult mice. This work may lead to the development of a practical potency test.