Obtaining and comprehensive evaluation of diagnostic serum to Yersinia pseudotuberculosis antigen, isolated using dimethyl sulphoxide

The aim of the study is to obtain hyperimmune blood sera of guinea pig and rabbit using an antigen isolated from Yersinia pseudotuberculosis cells using dimethyl sulfoxide, as well as to study the possibility of complex use of the obtained specific antibodies in indirect enzyme immunoassay (ELISA) for the detection of Yersinia. To obtain hyperimmune sera, a mixture of antigen and adjuvant was used in a ratio of 1:1. Proteins predominated in the composition of the antigen. It was administered to animals in the amount of 0.6 mg per guinea pig and 2 mg per rabbit. 1 % polyazolidinammonium modified with iodine hydrate ions was used as an adjuvant. Animals were immunized subcutaneously five times with an interval of 2 weeks. The resulting sera showed generic specificity in ELISA against Yersinia enterocolitica and Yersinia pseudotuberculosis (1:6400-1:25600). Their interaction with Escherichia coli, Salmonella typhimurium, Proteus vulgaris, Enterobacter aerogenes, Brucella abortus was insignificant (1:100-1:400). The complex use of specific hyperimmune blood sera from two animal species made it possible to conduct indirect ELISA for antigen detection. To do this, we adsorbed guinea pig antibodies on the surface of microplate wells. Then, with the help of rabbit serum, an indication of the antigen attached to the guinea pig antibodies adsorbed on the microplate was carried out. Rabbit antibodies were detected with a peroxidase antispecies conjugate. The complex use of experimental sera made it possible to detect enteropathogenic Yersinia in the accumulation medium even under conditions of significant fecal contamination of the test material already on the 3rd day of “cold enrichment”, provided that at least 50 Yersinia cells were added to 1 ml of the accumulation medium.