[Immunochemical studies of antigen K 88 from E. coli strains isolated from pigs]

Experiments were carried out to isolate, purify, and concentrate the K 88 antigen of Escherichia coli organisms. Employed were two purification methods --isoelectric precipitation, and immunoadsorption. The content of protein and carbohydrates was determined. The amino acid analysis revealed that the antigen contained 17 amino acids, mostly represented being asparagic acid, glutamic acid, and alanine. It was found that antigen K 88 obtained by the two methods was purified up to the state of homogeneity: in electrophoresis a band strip was produced, and in immunodiffusion and immunoelectrophoresis the antigen produced a precipitation arc against the homologous complete antiserum. In the elimination of K 88 in DEAE-Sefadex A-50 one peak only was present. The purified K 88 antigen was shown to possess good immunogenic properties. Sera obtained after hyperimmunization were with titres ranging from 1:640 to 1:1280, and they produced agglutination only with strains containing antigen K 88.