Antigenic Relationship of the Gram-negative Organism Causing Canine Abortion to Smooth and Rough Brucellae

Abstract

The use of whole-cell antigens in agglutination and agglutinin-absorption tests showed that the organism causing abortion in dogs is similar to rough Brucella abortus, B. melitensis , and B. ovis , but different from smooth Brucella cultures. Water-soluble antigens obtained by ultrasonic treatment and examined by immuno-electrophoresis and gel diffusion show extensive cross-reactions within the genus Brucella , but little or no cross-reaction with similar antigens from other gram-negative genera in the family Brucellaceae . The dog organism showed near identity with rough and smooth Brucella cultures on the basis of immuno-gel diffusion tests with water-soluble antigens, but it lacked the lipopolysaccharide-endotoxin associated with the agglutinogen of smooth brucellae. These findings support the proposal of Carmichael and Bruner for the designation of a new species, “ Brucella canis .”