Development of a Reagent for Evaluation of Incipient Immune Response to the Live Plague Vaccine

Objective of the study is to develop a reagent for the detection of lymphocytes with Yersinia pestis F1 antigen receptors. Materials and methods. Utilized have been: live plague vaccine based on the strain of Yersinia pestis EV NIIEG, formalin killed suspensions of microorganisms - Y. pestis , 3123, Y. enterocolitica O9 H-383 serovar, Y. pseudotuberculosis O1 2841 serovar; acetaldehyde-immobilized capsular antigen of Y. pestis F1 (obtained applying Baker methodology), lipopolysaccharide of Y. pestis K1, and bovine erythrocytes. Bovine erythrocyte F1 sensibilization has been performed using rivanol. Lymphocytes from blood have been isolated in density gradient ficoll-verografin 1.077. Lymphocytes with Yersinia pestis F1 antigen receptors have been detected by means of reagent adhesion onto the isolated lymphocytes. F1-free erythrocytes serve as controls. After the exposition, 7 evaluations of specificity to F1 and the lymphocytes, binding control reagent, have been carried out. Deployed have been 8 rabbits, immunized with live vaccine EV, and 2 rabbits, immunized with inactivated vaccine EV. Examined have been EV-vaccinated 5 persons. Results and conclusions. Identified is optimum sensibilizing dose of F1 antigen (250 µg/ml). Specificity of lymphocytes with receptors to F1 is demonstrated in inhibition experiments applying homologous and heterogeneous antigens. Lymphocytes with receptors to F1 (LRs) have been detected in peripheral blood of all rabbits and humans, immunized with vaccine EV. LRs have been registered since day 2 till day 35 in the rabbits, and in humans - since day 2 till day 14 after vaccination. It is shown that in case of revaccination of humans, LRs emerge and disappear earlier, than in case of primary immunization