HUMORAL AND CELLULAR-RESPONSE IN CALVES VACCINATED WITH BRUCELLA-ABORTUS RB51

The humoral and cellular response to a Brucella abortus RB51 vaccine i n calves was studied. The results show that after vaccination with B. abortus RB51, the animal remained seronegative for rose-bengal test, i ndirect ELISA and gel immunodiffusion test. However, the calves showed a strong T cell sensitization: when their lymphocytes were confronted in vitro with protein extracted from Brucella abortus strain RB51 an important increase of DNA synthesis was induced. The vaccinated animal s also gave a positive skin test to the antigen, with great mononuclea r infiltration. It was also observed that the polymorphonuclear leukoc ytes obtained from vaccinated animals showed a stronger capacity to el iminate Brucella as compared with non vaccinated controls.