Aim. A comparative study of serological methods for the detection of the causative agent of tularemia and their evaluation. Materials and methods. We used experimental diagnostic kits and test systems for the production of serological methods: indirect hemagglutination reaction (RGA); the reaction immunofluorescence (RIF); enzyme immunoassay (ELISA) using traditional microplate; IFA after selective concentration of the pathogen of tularemia in magnoimmunosorbents (MIS); microgravimetric analysis (MGA) based on piezoresistors (SP) and surface plasmon resonance (SPR). The experiments were carried out with homologous strains of tularemia microbe (test strains) and with strains of heterologous microorganisms in model experiments on tap water contaminated with different concentrations of the pathogen. Results. The parameters of each diagnostic method are determined and evaluated according to the following indicators: sensitivity (when working with pure cultures (test strains), contaminated samples of large volumes), specificity, time of setting and taking into account the results, informativeness, determining the modes of setting and accounting. Conclusion. The above diagnostic methods have their advantages and disadvantages. Therefore, when choosing a method, the researcher should be guided by the goals pursued. So, for screening studies it is advisable to carry out the formulation of ELISA, RIF, RGA, in identifying the pathogen in large volumes and contaminated samples, the effective use of selective concentration on MIS followed by the formulation of ELISA, to identify small amounts of samples and take into account the reaction in real time, it is possible to use MGA and SPR.

Regulatory framework and methodological approaches to evaluation of immunological effects of vaccination against brucellosis are not established, and the degree of immunological post-vaccinal rearrangement is not yet developed. Due to leading role of cellular immunity in formation of immune protection against brucellosis, evaluation the cellular response in response to antigenic stimulation may be considered the most informative and objective approach to analysis of immune changes in the body during vaccination. In order to develop the most diagnostically informative methods for design of antigen-stimulation cell tests in vitro, a careful selection of a stimulating agent (antigen) is required, which should have a sufficient activating potential, thus providing specificity of reaction under in vitro conditions. The aim of the present study is to study the in vitro specific activity of a protein-polysaccharide antigenic complex from the Brucella abortus 19 BA strain (BrAg), and an opportunity of its application in order to assess the formation of post-vaccinal cellular immunity against brucellosis.The study was performed with white laboratory mice (n = 50) immunized with the Brucella abortus 19 BA strain. The control group (n = 50) consisted of laboratory mice that received a sterile saline solution in a volume of 0.5 ml. Blood samples were taken from immunized and control animals before vaccination, and 7, 14, 21, and 30 days after immunization. By means of flow cytometry, the activation molecules CD25, CD69, MHC II and CD95, expressed on T lymphocytes (CD3+CD69+, CD3+CD25+, CD3+CD95+, CD3+MHC+) were determined. To observe the development of immunity, the intensity of expression of T lymphocyte activation markers was calculated using the stimulation quotient. BrAg was used for specific in vitro stimulation of T lymphocytes. The liquid brucellosis allergen (brucellin) was used as an antigen for comparison, when studying opportunity of BrAg usage for assessing the postvaccinal immunity development.The following results were obtained: BrAg has pronounced specific activity, it did not cause non-specific in vitro reactions (activation) of T lymphocytes, thus enabling its application as a test antigen when evaluating development of adaptive vaccine immunity against brucella.Experimental testing of brucellosis antigen for carrying out the in vitro antigen-stimulated cellular reactions, aiming for evaluation of post-vaccinal immunity development against brucellosis, showed that the usage of BrAg promotes increase in diagnostic sensitivity of cellular reactions under in vitro experimental conditions. The applied experimental antigen is a quite promising tool for development of laboratory algorithms for brucellosis diagnostics, and assessment of actual vaccination efficiency in cohorts previously vaccinated against brucellosis.

We described the results of studying the stability of the main indicators of medical product quality for in vitro diagnostics - diagnostic fluorescent tularemia dry immunoglobulins RIF-Tul-StavNIPCHI, developed on the basis of Stavropol Anti-Plague Institute of Rospotrebnadzor to justify the shelf life and recommended storage conditions when used on a real scale time and accelerated research methods. At the same time, one of the main criteria for the study of stability is its study during sample storage not only in the primary packaging of an industrial output, but also after the first opening of the package, during the use period of the reconstituted preparation. On the basis of data obtained in both long-term and accelerated trials, a shelf life of three years is recommended. It was experimentally proved that during this period of time, the quality indicators of the drug remain at a level one that complies with the requirements of technical and operational documentation. In the course of application the recovered product demonstrates stability of its biological and physical-and-chemical properties within 5 days at a storage temperature of 2 to 8°С.

The aim of the work was to implement the risk management strategies in the manufacturing and use of medical products for in vitro diagnostics by the example of the experimental series of the reagent kit “Lyophilized erythrocyte antigenic tularemia diagnosticum”.Materials and methods. We tested experimental series of the reagent panel “Lyophilized erythrocyte antigenic tularemia diagnosticum”. To carry out the identification, assessment and analysis of risks regarding the considered medical product, failure mode and effects analysis (FMEA) was proposed and adapted under production conditions. Identification of risks associated with manufacturing and control of medical products for in vitro diagnostics was carried out using technological regulations, standard operational procedures and manufacturing notes.Results and discussion. The main outcome of the study is the development of a corrective actions system aimed at reducing the risks and ensuring consistent monitoring. The proposed schemes for carrying out the risk management process can be used as standard ones in the design and development of medical products for in vitro diagnostics, taking into account the specifics of each individual manufacturing. The reporting documents developed within the framework of the system are applicable during the inspection of good manufacturing practice and in terms of completing the registration profile of a diagnostic product with subsequent registration in the healthcare system of the Russian Federation.

Anthrax poses a pressing issue for veterinary medicine and public health in many countries, including the Russian Federation, which necessitates the improvement and development of new, sensitive and specific diagnostic tools.The aim of the work was to create an experimental peroxidase conjugate for the detection of specific antibodies to the anthrax pathogen and to optimize the conditions for performing enzyme immunoassay (ELISA).Materials and methods. The peroxidase conjugate was constructed using horseradish peroxidase and Staphylococcus aureus protein A (Sigma-Aldrich, USA). Bacterial antigens isolated from strains of Bacillus anthracis 55ΔTPA-1Spo, B. anthracis Sterne 34 F2 were used as sensitizing agents. The developed experimental batches of the conjugate were tested in ELISA for the ability to bind antibodies in the blood sera of anthrax patients and vaccinated individuals. The sensitivity, specificity, and accuracy of the method were calculated using the built-in functions of the ROCR software package.Results and discussion. The peroxidase conjugate to detect specific antibodies to the anthrax pathogen in the study of clinical material has been developed; conditions for the ELISA performance have been optimized. To interpret the results of the study, a threshold value of the positivity coefficient was used, below which the result was considered negative, and at an equal or higher value, positive. The test demonstrated significant differences in the “positivity coefficient” indicator for the “Healthy”/“Sick” and “Healthy”/“Vaccinated” groups, while the differences between the “Sick”/“Vaccinated” groups were statistically insignificant. The maximum accuracy of the method was observed at blood serum dilutions of 1:250 and 1:500. 100 % intra-run, run-to-run and series-to-series reproducibility has been established for all positive samples. The sensitivity and specificity of the experimental peroxidase conjugates were 100 and 95.8 %, respectively, and the accuracy was 97.6 %.