Experimental approach to immunomodulatory drug selection to improve plague vaccination efficacy

Goncharova A.Y., Bugorkova S.A.

Russian Research Anti-Plague Institute "Microbe" of the Federal Service for Surveillance on Consumer Rights Protection and Human Well-Being, Saratov, Russia

Introduction. The unification of the approach to immunomodulatory drug (ID) selection to increase the efficacy of existing and developing vaccines for infectious diseases, in particular the live plague vaccine (LPV), reduces labor costs and risks when conducting studies using biomodels of the infectious process.

The aim is to develop and test an experimental and methodological approach to the selection of commercial ID in order to potentiate the action of LPV.

Materials and methods. Vaccine strain Yersinia pestis EV line NIIEG, ID – azoximer bromide (PO), recombinant human interferon gamma (RHI), and the low molecular weight oligopeptide gepon (GP) were used in plague vaccination schemes. Predictors of the specific immune response of the plague microbe were determined by enzyme-linked immunosorbent assay. The protective effectiveness of the tested vaccination regimens was evaluated against the virulent Y. pestis 231(708) test strain in experiments on BALB/c mice.

Results. According to the results of the evaluation of the effectiveness of the combined use of LPV with ID, it was found that PO and RHI, but not GP, contribute to the activation of humoral and cellular responses, as well as increase the protective effectiveness of the EV vaccine strain, contributing to a decrease in ED50, an increase in survival and average life expectancy of animals, depending on the immunization regimens used, selected based on the potentiating mechanism of ID action. Thus, the effectiveness of the proposed methodological approach to the selection of ID for inclusion in the schemes of specific plague prevention has been experimentally substantiated.