According to the results of ten kethes of 1yophili swine erysielas live vaccine, it was notad that the living kazteria nusncer bofore lyophilizing is 6.7 times (4.5 to 9.6 times) of that 1yophilil. In order to gepaxe a satisfactory vaccine, it is neressaq to adjust the living Inria numker (l:efccxe lyophilizing) to 10 times of that exp. Five groups of mice (10 of each group) were suboutansusly incculated with 0.1 ml dilution of 1yophiliI vaccine titered 5X1Ohnl, 10”Ohnl, SXlfl)ml, 1Ohnl, and 10” (S)ml, restive1y. Two weks aft vaccination, all the mice were challenged with virulent stain of the swine erysi1as ctia. Eighty rer cent of the mice vaccinated withvathnetitered5Xl(Y’(lsurvisvedofthechallenge, while 1(X)% ofthe mice vaccinatol with vaccine titererl SX1C$Ohnl showed no clinical signs and survived.
Using agglutination test antibcdy could Ire denl in the vaccinati. piglet one ummary week ptet-vaccination, and, the antibody level reached 40x or more when the vaccine titered 10’ Ohril was used. The antibcxly titer remained at 80x eight weeks postvaccination,
Four weeks aft vaccination, piglet with agglutination antibody level of 40x, 1 and EAOx, respeDtively together with unvaccinated contol were challenged with virulent erysielas Ictria. The challenged contol showed severe clinical signs, piglet, with antibody level 40x got sick slightly, while the other groups (titer lEOn and 640n) had no clinical signs at all. In conclusion, the mice can ke used for the bicessayofthe erysielas vaccine. The vaccine, which is effeetive in gotting mice from challenge is also effective in gotzting swine. The effective ji’otecting antibody level was maintained in pigs for only 3-4 months when the vaccine titered 1O”Ohnl was used.