IMMUNIZATION AGAINST BRUCELLA INFECTION. 10. THE RELATIVE IMMUNOGENICITY OF BRUCELLA ABORTUS STRAIN 19-BA AND BRUCELLA MELITENSIS STRAIN REV I IN CYNOMOLGUS PHILIPPINENSIS.

Continuing previous studies, the authors investigated the immunogenicity of low doses of Brucella melitensis strain Rev I in Cynomolgus monkeys challenged by the respiratory route and compared the efficacy of Rev I vaccine with that of vaccine from Br. abortus strain 19-BA.Challenge with the virulent Br. melitensis strain 6015 indicated that 19-BA vaccine was considerably more effective when administered intracutaneously than subcutaneously, whereas with Rev I vaccine the difference was slight, but Rev I conferred immunity in much lower doses. It was found that a dose as low as 260 cells of Rev I led to a high degree of immunity, although there was a very pronounced delay in the bacteriological response. The authors conclude that the results obtained justify trials of the safety of Rev I vaccine for man in the low dosage effective for cynomolgi.