Summary
In Venezuela, 1,012 cattle sera were screened for their ability to precipitate Brucella melitensis 16M smooth-lipopolysaccharide (s-lps), B melitensis B115 polysaccharide B (poly B), B abortus 1119-3 O-polysaccharide (ps), or B abortus 1119-3 cyclic 1,2 linked β-d-glucan (β-glucan) in an agar-gel immunodiffusion assay. These sera were previously classified as being Brucella abortus-infected, S-19-vaccinated, or negative after an assessment of historical records and results of 5 standard serologic tests. Most of the sera (85%) from infected cattle precipitated s-lps, poly B, and ps. Serologic results for poly B and ps were identical. On the other hand, 13% of the sera from vaccinated cattle precipitated s-lps, but none of these sera precipitated poly B or ps. It was concluded that purified ps can alternate with poly B as an antigen to differentiate sera of B abortus-infected from B abortus S-19-vaccinated cattle. None of these sera precipitated β-glucan.
