STUDIES ON IMMUNITY TO HEMOPHILUS-PLEUROPNEUMONIAE INFECTIONS IN MICE

  • 1 January 1982
    • journal article
    • research article
    • Vol. 43  (10) , 1793-1798
Abstract
A murine model of experimentally induced H. pleuropneumoniae respiratory tract infections was developed and used to evaluate the efficacy of bacterins. Various doses of 3 H. pleuropneumoniae strains (serotype 1 and 5) were administered intranasally (i.n.) to groups of anesthetized Swiss White mice. The accumulated mortality per group at 5 days after they were inoculated was used to calculate the LD50, which ranged between 1.4 .times. 106 and 5.4 .times. 107 bacteria. There was correlation between dose administered, incubation period of the disease and mortality. The induction of H. pleuropneumoniae disease in the mouse was reproducible and resembled that of naturally occurring porcine H. pleuropneumonia. The murine model of exposure was used to evaluate the efficacy of H. pleuropneumoniae serotype 5 (strain B78-3760) bacterins administered s.c. and i.n. Vaccination by s.c. route induced slightly higher titers of specific seroagglutinins, compared with the response induced by the i.n. route, and the former was effective in protecting mice against i.n. challenge with H. pleuropneumoniae. Vaccination was not efficacious in mice given a challenge dose > 1.2 LD50. The percentage survival rates in the s.c. and i.n. vaccinated mice were significantly greater than in the control groups at P. < 0.01 and P < 0.05, respectively.