The production of hyperimmune pseudotuberculosis sera

Background . Pseudotuberculosis remains a serious public health problem, which dictates the need to develop simple and rapid diagnostic methods for this disease. The effectiveness of the latter largely depends on the activity and specificity of the diagnostic sera. Currently, in our country, a diagnostic serum for Yersinia pseudotuberculosis O-monovalent (serotype I, III) is produced with a regulated area of application: for an approximate agglutination reaction on glass (Pasteur NIIEM, St. Petersburg). Preparation of pseudotuberculosis sera for a wider scope of their use, in particular, as a  source of specific antibodies in the design of diagnostic immunobiological preparations and test systems for pseudotuberculosis, is relevant and in demand in healthcare practice. Aims . To obtain hyperimmune pseudotuberculosis sera, promising for use in the practice of laboratory studies for pseudotuberculosis. Materials and methods. Chinchilla rabbits aged 3–6 months, weighing 2.5–3.0 kg served as animal producers of pseudotuberculosis sera. As immunogens, we used a corpuscular antigen (CAg) - a suspension of cells of the epidemically significant Yersinia pseudotuberculosis 3704 O: 1b strain isolated by an outbreak of pseudotuberculosis in the town of Zima, Irkutsk region, inactivated by boiling, and a preparation obtained from the outer membranes, containing the main surface immunogen of the strain. For the adsorption of experimental sera, in order to minimize the nonspecific response, we used heterologous microorganisms Escherichiacoli, Salmonella typhimurium, Shigella flexneri and Y. enterocolitica O:3, which have a similarity of surface antigenic structures with the causative agent of  pseudotuberculosis. The presence of specific antibodies in experimental pseudotuberculosis sera was determined in a volumetric agglutination reaction. Results . Optimal schemes of rabbit immunization were selected, which made it possible to obtain hyperimmune sera against Y. pseudotuberculosis 3704 O:1b antigens with an agglutination activity of 1:3200-1:6400. In low dilutions of experimental sera (1:100–1:400), obtained against corpuscular antigen and outer membrane antigens (Escherichia coli, Salmonella typhimurium, Shigella flexneri , Y. enterocolitica О:3, S . enteritidis Gartnery) was observed in the agglutination reaction (AR). After the adsorption of experimental pseudotuberculosis sera by cells of heterologous strains, there was no cross-reaction with the indicated microorganisms in the  agglutination reaction. Conclusions . The obtained hyperimmune adsorbed sera against the boiling-inactivated Y. pseudotuberculosi s 3704 O: 1b corpuscular antigen and outer membrane antigens can be used as a source of specific antibodies in the design of diagnostic immunobiological preparations for the detection of pseudotuberculosis microbe, as well as in the monitoring of the epidemic situation.