EXPRESSION OF RECEPTORS UNDER THE INFLUENCE OF ATTENUATED VACCINE STRAINS AND WILD STRAINS OF VARICELLA ZOSTER VIRUS IN VIVO

Abstract

The prevention of diseases caused by the varicella zoster virus (VZV) through vaccination is a priority of the World Health Organization's program for the eradication of socially significant and demographically important infections, integrated into the Russian Federation's health development program, one of the directions of which is the inclusion of varicella zoster vaccination in the National Calendar of Preventive Vaccinations. A mathematical model based on epidemiological data predicts that vaccination coverage should be at least 60% in order to ensure a significant reduction in the incidence of chickenpox, and while maintaining an adequate level of coverage, the incidence of herpes zoster is likely to decrease in the long term. The successful use of live vaccines for the prevention of diseases associated with high-risk diseases is expanding the number of registered vaccines and countries that have included vaccination in national immunization programs. The development of a domestic vaccine is a prerequisite for the implementation of the import substitution program. The Mechnikov Research Institute of Vaccines and Sera has isolated and characterized wild strains of VZV that can be used to create vaccines. Standard methods for studying the effectiveness of live varicella zoster virus vaccines are the determination of adaptive immunity parameters based on such indicators as the total level of antibodies to varicella zoster (GMI), geometric mean antibody titers (GMT) at certain time intervals, geometric mean multiple increase (GMFI) of antibodies to VZV over the same time period, and the level of seropositivity (defined as the percentage of subjects with an antibody titer > 1:8). However, the assessment of the effect on innate immunity is not studied routinely, only within the framework of scientific research. To evaluate the innate immune response, as one of the options for investigating the effectiveness of vaccination, the expression of Toll-like receptor (TLR) genes in response to vaccine administration can be used. TLR genes encode receptors that recognize the structural components of RNA and DNA-containing viruses, including the varicella-zoster virus. The expression levels of TLR2, TLR4, and TLR9, in turn, are markers of innate immunity activity, which are extremely important in response to the introduction of vaccines. Due to the course of this scientific work, varicella zoster virus strains obtained in the laboratory of the I.I. Mechnikov Research Institute of Vaccines and Sera were evaluated for their ability to induce an innate immune response using TLR2, TLR4 and TLR9 markers. The results obtained made it possible to identify the optimal experimental sample for further study in the direction of obtaining an effective vaccine against infections caused by the varicella zoster virus.