Dynamics of Changes in the cAMP/cGMP Concentration Ratio in the Thymus and Spleen of Laboratory Mice during Vaccination against Plague and Tularemia against the Background of Immunomodulation.

Vaccine strains Yersinia pestis EV NIIEG at a dose of 103 CFU and Francisella tularensis 15 NIIEG at a dose of 102 CFU induced changes in the concentration of cyclic nucleotides in the thymus and spleen of white mice. Antigen-induced changes in the cAMP/cGMP ratio in immunocompetent organs had a phase or oscillatory character, which seems to be related to the regulation of postvaccination immunoreactivity in the body. Synthetic organoselenium compound 974zh stimulated an increase in the amplitude of cAMP/cGMP oscillations, indicating its stimulating effect on the immunogenic properties of vaccine strains at doses an order of magnitude below the standard doses.

The Influence of the Synthetic Organoselenium Preparation 974zh on the Immunogenic Activity of Yersinia pestis EV Vaccine Strain NIIEG.

In the present study, a stimulating effect of a new synthetic organoselenium compound 2,6-dipyridinium-9-selenabicyclo[3.3.1]nonandibromide (974zh) on the immunogenic activity of the vaccine strain Yersinia pestis EV NIIEG was revealed. After infection with the virulent plague strain, the survival rate of laboratory mice immunized with the vaccine strain grown on Hottinger's agar in the presence of 974zh (300 µg/ml) increased in comparison with control animals immunized with the Y. pestis EV NIIEG culture grown on agar without the studied compound. Plasmid screening of cultures grown on medium with and without 974zh showed that plasmid DNA of Y. pestis EV culture grown in the presence of 974zh had broader bands in the control grown without 974zh. This phenomenon can indicate activation of replication of plasmid DNA of Y. pestis EV under the influence of the experimental compound.

Peculiarities of Humoral Immunity Formation in Medical Institution Employees Recovered from or Vaccinated against COVID-19 in Irkutsk.

We performed a seroepidemiological survey of the level and structure of population immunity to SARS-CoV-2 among employees of medical institution in the Irkutsk region during the COVID-19 pandemic. Seroprevalence assessment was organized from May 2020 to April 2021. The level of antibodies to SARS-CoV-2 was measured by ELISA. It was found that 139 (46%) of 299 examined workers were seropositive, including 50 (36%) vaccinated against COVID-19, 75 (54%) patients diagnosed with COVID-19, and 14 (10%) asymptomatic cases of SARS-CoV-2. The results obtained should be taken into account when predicting the dynamics of the epidemic process and organizing preventive (antiepidemic) measures, including vaccination.

Effect of a Synthetic Organoselenium Compound on Post-Vaccination Immunopoiesis in the Red Bone Marrow and Cell Composition of Peripheral Blood of White Mice Vaccinated with Yersinia pestis EV.

We studied the effect of an experimental synthetic organoselenium compound 2,6-dipyridinium- 9-selenabicyclo[3.3.1]nonane dibromide (974zh) on the cell composition of the red bone marrow and peripheral blood in white mice. The study drug co-administered with Yersinia pestis EV vaccine strain (103 CFU) potentiated maturation and migration of mature neutrophils from the bone marrow into the circulation. Reducing the dose of the live vaccine and the anti-inflammatory properties of the study drug made it possible to reduce the allergic reaction during the vaccination process.

Antigen-Specific Activation of Blood Lymphocytes in Mice Immunized with Brucella abortus 19 BA.

We studied the expression of activation markers CD25 and CD69 by blood lymphocytes in white mice vaccinated with Brucella abortus 19 BA in antigen-specific tests in vitro. During incubation of blood lymphocytes with brucellosis polysaccharide-protein antigen, a statistically significant increase in the expression of CD25 by B cells and CD69 by T cells was observed; brucellin increased the expression of CD25 by B and T cells. Comparative analysis of the action of antigen preparations B. abortus showed that only brucellin has antigen-specific activity against CD19+CD25+ cells. The used method can be considered as a promising test for evaluation of the effectiveness of brucellosis immunoprophylaxis, which substantiates the need for further research.

Effects of Thermoextracts of Brucella S and L Forms on Lipid Peroxidation and Antioxidant Defense in Organs of Laboratory Animals.

The dynamics of LPO marker malondialdehyde formation and peroxidase-destroying activity was studied in homogenized organs of guinea pigs, immunized with thermoextracts from S and L forms Brucella abortus I-206. The L form brucella thermoextract exhibited a lower reactogenicity and adequately activated the antioxidant system, due to which the destructive effects of ROS could be partially neutralized during the vaccinal process.