Studies on the Immunization of Guinea Pigs and Mice to Brucella Infection by Means of the “Native Antigen”

Abstract

The “native antigen” of Brucella suis is capable of inducing immunity in guinea pigs and mice to 10–200 minimal infective doses. The degree of immunity conferred on both animal species was, under certain conditions, such that between 75 and 80 per cent of the animals subsequently cleared their tissues of cultivable Brucella within one month of infection. No single variable in the administration of the vaccine was specifically effective in altering the results. Hypotheses are offered to account for this. The bactericidal action of whole blood of vaccinated guinea pigs has not as yet served as a reliable index of the immune state of the animal. Vaccination with “native antigen” did not confer a state of cutaneous hypersensitivity on the guinea pigs.