抄録
Immunity in chickens with killed organisms of Mycoplasma gallisepticumwas evaluated according to the lesion grade of airsacculitis, the retention of M. gallisep-ticum in organs and histopathological findings. Killed M. gallisepticum did not provideany resistance when intramuscularly administered either alone or in admixture withadjuvants. An increased resistance to infection, however, was observed when it was administered into the respiratory tract in a form of aerosol or by intratracheal injection.A partial immunity was maintained at a significant level for at least 3 months. Theseresults suggest that protection of chickens against M. gallisepticum infection may be pos-sible when the killed vaccine is applied directly to the lower respiratory tract of thechickens. The suggestion is supported by the histopathological findings of specimens col-lected from immunized birds. Little correlation was seen between serological serum titerand resistance to challenge.
