Abstract: A method is disclosed for discriminating between cattle vaccinated against and those infected with Brucella spp. The method involves immunoassay using a purified polysaccharide containing 4,6-dideoxy-4-acylamido-D-mannopyranosyl units obtained from B. abortus or from cross-reacting organisms, and results in improved differentiation between vaccinated and infected animals. Test kits are also disclosed for performing the assay and a process is disclosed for obtaining the O-chain polysaccharides in high purity and yield.

Abstract: The antigenic O-chain polysaccharides from Brucella abortus and Yersinia enterocolitica serotype 0:9 have similar structure, i.e. 1-2 linked 4,6-dideoxy-4-formamido-.alpha.-D-mannopyranosyl units. The antigen is more readily isolated from the Yersinia and may be chemically modified to have a hydrophobic moiety attached thereto. The antigen can be adsorbed or coupled to carriers suitable for immunoassay use such as ELISA and RIA. A monoclonal antibody capable of specifically binding to B. abortus and Y. enterocolitica, has been produced. Assay procedures and kits therefor, are described.

Abstract: Monoclonal antibodies specific to Neisseria gonorrhoeae lipopolysaccharide components having no cross-reactivity with N. meningitidis have been produced and found useful in the diagnosis of the presence of N. gonorrhoeae.

Abstract: A reagent and test for the identification of the bacterium Neisseria gonorrhoeae. Lipopolysaccharide antigen, found to be common to N. gonorrhoeae strains, is used to inoculate fowl, and serum from the fowl recovered containing antibodies causing agglutination of cells of all N. gonorrhoeae strains. The identification test comprises adding the recovered antibody reagent to a suspension of bacterial cells, the occurrence of cell agglutination being a positive test for N. gonorrhoeae.