[Use of specific antibodies, labeled with colloidal gold particles, for the detection of Brucella antigens using dot-immunoassay].

The method of dot immunoassay with the use specific antigens, labeled with colloidal gold particles, for the detection of brucellar antigens was developed and tested under laboratory and field conditions. In this work soluble antigens isolated from different Brucella species and corpuscular antigens (13 strains belonging to 7 species of the genus Brucella, most pathogenic for humans and animals in the S- and R-forms) were used. The method was tested in the study of pathological material obtained from sick animals and humans in a farm with unfavorable situation for brucellosis in the Irkutsk Region. The sensitivity of the proposed assay system was found to be high and constituted 10 pg/ml to 1 ng/ml for soluble brucellar antigens and 200 CFU/ml to 13.5 x 10(6) CFU/ml for corpuscular antigens of Brucella S- and R-forms. The specificity of the method was tested with the use of 10 heterologous microorganisms. False positive results were observed only with Yersinia enterocolitica 0:9 at a concentration of 1 x 10(6) CFU/ml due to similarity of their polysaccharide-containing surface antigens. The newly developed dot immunoassay is simple for use, rapid and does not require expensive reagents and equipment.