Immunogenic properties of soluble antigens or whole cells of Brucella abortus strain 45/20 associated with immunoadjuvants. II. Whole cells.

Whole cells of Brucella abortus strain 45/20 were combined with trehalose dimycolate or muramyl dipeptide. These preparations were tested in guinea pigs for immunogenic properties. Both trehalose dimycolate and muramyl dipeptide were found to be effective adjuvants to whole cells when combined in oil emulsions. Although saline suspensions of whole cells or whole cells-muramyl dipeptide did not significantly reduce splenic infections, oil emulsion or whole cells-trehalose dimycolate in oil droplet emulsion were both effective immunogens (P < 0.05). Oil emulsions of whole cells-muramyl dipeptide reduced mean splenic Brucella by 95.1% and those of whole cells-trehalose dimycolate reduced mean splenic Brucella by 99.3% as compared to the control animals.