Experimental study of brucella vaccines in mice and guinea pigs, with special references to serological diagnosis of workers in field of vaccine production

Abstract

In this study, groups of 150 brucella free white Swiss mice, were inoculated with different oily adjuvanated brucella melitensis subunit vaccines alone or both and then were challenged with Br. melitensis virulent strain for the evaluation of the immune response of each subunit vaccine which was judged by testing this potency through spleen to body weight ratio and the number of brucellae per gram spleen. Also two groups of brucella free guinea pigs were inoculated with a combination of different oily adjuvanated Brucella melitensis subunit vaccines combined with either live attenuated Br. abortus strain 19 vaccine, inoculated conjunctivally or RB51 vaccine injected subcutaneously. Then the animals were challenged with virulent Br. melitensis strain. Humeral and cell mediated immune responses were evaluated. The shedding of the vaccinal strains in the different body secretions was detected along the whole days of the experiment. Eighteen serum samples were collected from occupational group working in the vaccine production and application for serological examination. It was found that the protection level in the different mice animals groups was 70%, while in the vaccinated guinea pigs vaccinated with the combined oily adjuvanated Br. melitensis subunit vaccine combined with strain 19 vaccine, was 90%, while in those combined with RB51 vaccine, the protection level was 85%. In addition, no vaccinal strains were detected in the different body secretions of the vaccinated animals along the whole days of the experiments. Only two cases of the occupational group were positive.