Introducion. Ricin is a glycoprotein phytotoxin that is characterised by high toxicity and relatively simple extraction methods. Monoclonal antibodies (mAbs) against ricin represent a key component in the development of immunodiagnostic test systems and preparations for the specific prevention and treatment of toxin poisoning. The aim of the present study was to obtain and characterise mouse monoclonal antibodies specific to the ricin B subunit. Materials and methods. Monoclonal antibodies were produced using a hybridoma technology, with the recombinant ricin B subunit (RTB) having been used as the antigen for immunising BALB/c mice. Hybridisation was performed by electrofusion, using the Sp2/0-Ag14 myeloma cell line as the partner cells. The stable hybridoma production was then carried out in vivo in mice. The specificity of the obtained mAbs was then assessed by Western blotting against RTB and native ricin. The parameters of the affinity interaction between the obtained antibodies and RTB were determined by surface plasmon resonance. The selection of the optimal antibodies pair for RTB detection was determined using a sandwich-format enzyme-linked immunosorbent assay (ELISA). In order to assess the neutralising activity of the antibodies against ricin, in vitro tests were carried out using the Vero В cell line, and in vivo tests were conducted using a mouse model. Results. Consequently, 13 mAbs specific to RTB and ricin were obtained and characterised. Following a thorough evaluation of the strength of affinity interaction and the selection of optimal antibody combinations for RTB detection, it was determined that four mAbs (RTB-F1-2, RTB-F1-16, RTB-F2-10 and RTB-F5-1) were identified as promising candidates for the purpose of developing diagnostic test systems. mAbs RTB-F1-15, RTB-F1-16, RTB-F2-10 and RTB-F5-1 demonstrated significant neutralising activity in in vitro tests against ricin at a dose of 8 × IC50. Intravenous administration of the mAbs RTB-F2-10 ensured 100% survival of mice following intraperitoneal ricin intoxication at a dose of 3 × LD50. Conclusion. The feasibility of utilising high-affinity mAbs (RTB-F1-2, RTB-F1-16, RTB-F2-10 and RTB-F5-1) for the design of diagnostic test systems has been demonstrated through experimental means. The data obtained on the neutralising properties of the mAb RTB-F2-10 in in vitro and in vivo tests allows it to be considered as a basis for the development of a therapeutic agent using chimerisation and humanisation strategies.
The global monkeypox outbreak in 2022, which affected more than 120 countries, marked the transition of this disease from an endemic condition to a global public-health threat. A decline in herd immunity following cessation of routine smallpox vaccination, together with the insufficiency of existing vaccines, underscores the necessity for development of new immunoprophylactic measures against monkeypox. The aim of this review is to summarize the evidence on contemporary candidate vaccines against monkeypox developed using different approaches. To prepare this review, a literature search was conducted in PubMed, Scopus, Elsevier, Google Scholar, and RSCI up to August 2025. The following keywords were used: MPXV, Monkeypox, vaccine, monkeypox virus. The review addresses both classical live attenuated vaccinia virus-based vaccines, previously approved for prevention of monkeypox, and vaccines being developed using recombinant technologies, including DNA and mRNA vaccines. Their immunological characteristics, safety profiles, and potential for further clinical application are presented.
Introduction. Mycoses (fungal infections) represent a serious global health threat: more than 6.5 million severe invasive cases of such diseases are registered annually worldwide, accompanied by extremely high mortality (on average 68%). The high degree of threat determines the relevance of intensifying research into the mechanisms of fungal drug resistance, the pathogenesis of the fungal diseases, as well as the development of more effective therapeutic approaches. The implementation of methods that combine high analysis speed with accurate quantitative assessment of viable microorganisms is a key condition for obtaining reproducible research results both at the stage of culture preparation for in vivo infection modeling and when evaluating the efficacy of antifungal drugs. Aim of this study was to develop and evaluate the application of flow cytometry for rapid quantification of microorganisms using Candida albicans fungi as an example, both in pure culture and in multicomponent samples, in comparison with the CFU counting method. Materials and Methods. To model infection, female BALB/c mice were intravenously inoculated with C. albicans isolate GIMC100:CaMK2014SRP at doses of 0.5 × 10⁶, 1.0 × 10⁶, and 2.0 × 10⁶ CFU/animal. The number and viability of C. albicans cells were assessed by culture-based and flow cytometric methods using species-specific FITC-labeled antibodies and propidium iodide. Results. Flow cytometry allows rapid counting of C. albicans in samples, showing measurement accuracy comparable to the CFU counting method across a wide range of pathogen concentrations (from 100 to 1 million cells). The use of pathogen-specific fluorescently labeled antibodies and a viability dye makes it possible to reliably detect live C. albicans cells in samples regardless of the presence of impurities (debris, eukaryotic cells, dead C. albicans cells), without reducing counting accuracy. Conclusion. Having no alternatives with similar characteristics, the proposed method appears to be highly demanded for the standardization of C. albicans samples for modeling candidiasis in laboratory animals. Furthermore, this method is seen as a promising alternative to the conventional method of CFU counting on solid nutrient media for determining the number of live C. albicans cells when analyzing biological samples or evaluating the efficacy of antifungal drugs in culture.
Background. Streptococcus pyogenes (group A streptococcus, GAS) is a significant human bacterial pathogen causing a wide range of diseases, from upper respiratory tract infections to severe invasive forms. The increase in incidence in the post-COVID-19 period and the spread of hypervirulent clonal lineages, including M1UK (emm1 genotype), highlight the need for molecular genetic surveillance. Aim. To characterize the clonal structure, virulome and resistome of S. pyogenes strains isolated from hospitalized children and to assess their phenotypic antimicrobial susceptibility. Materials and methods. A total of 67 S. pyogenes strains isolated in 2023–2024 from hospitalized patients aged 0–17 years were studied. Identification was performed by MALDI-TOF mass spectrometry. Antimicrobial susceptibility testing was carried out by serial dilution methods. Whole-genome sequencing, genome assembly were performed. Bioinformatic analysis included emm typing, multilocus sequence typing, detection of virulence and antimicrobial resistance genes, and phylogenetic analysis. Results. Fourteen emm types and 19 sequence types were identified. The predominant clonal lineages were emm6/ST382 (16.4%), emm2/ST55 (14.9%), emm3/ST15 and emm75/ST49 (10.4% each). A strong association between emm and sequence types was observed (p 0.001; Cramer's V = 1.0). One strain of the M1UK lineage was identified among emm1/ST28 isolates. The virulence genes sagA, slo, mf/spd and speB were detected in all strains, while hylP was found in 86.6%. Among superantigen genes, speG (89.6%) and speC (68.7%) were most frequent. All strains were susceptible to β-lactams, clindamycin, linezolid, vancomycin. Resistance to erythromycin and tetracycline was detected in 4.5% and 14.9% of strains, respectively, and was predominantly associated with the mef(A)/msr(D) and tetM genes. Conclusion. S. pyogenes strains isolated from hospitalized children are characterized by genetic heterogeneity, a pronounced clonal structure, and genotype-specific distribution of superantigen genes. The results confirm the importance of whole-genome sequencing for monitoring the clonal structure, virulome and resistome of S. pyogenes within molecular epidemiological surveillance of GAS infections.
Introduction. COVID-19, caused by SARS-CoV-2, remains a significant global health issue. Since late 2021, the Omicron variant has become dominant, characterized by high transmissibility but reduced virulence. Studying the regional characteristics of the epidemic process during its circulation is essential for assessing the transformation of the COVID-19 epidemic process and the emergence of circulation patterns approaching endemicity. Objective. Analysis of the epidemiological situation of COVID-19 in the Northwestern Federal District of the Russian Federation during the period of dominance of the SARS-CoV-2 Omicron variant. Materials and methods. An analysis of Rospotrebnadzor statistical data on morbidity, case fatality rate, age structure, and severity of COVID-19 in the Northwestern Federal District (NWFD) for 2022–2024 was conducted. To study genetic diversity, S-gene sequencing was performed on 16,008 samples from COVID-19 patients across 11 subjects of the Northwestern Federal District to determine the genetic lineages of circulating strains. Results. A decrease in annual morbidity was observed, from 1,768,558 cases in 2022 to 145,482 in 2024. Morbidity exhibited a wave-like pattern with peaks associated with the succession of Omicron subvariants. A shift in morbidity towards the 65+ age group was noted (an increase in proportion from 12.0% to 22.7%). The proportion of severe forms has decreased significantly (from 3.7% to 0.2%), and case fatality rate decreased from 4.4% to 0.2%, while the proportion of mild and asymptomatic cases increased. Conclusion. The data suggest the emergence of features of SARS-CoV-2 circulation in the NWFD approaching an endemic pattern, accompanied by a decrease in severe cases and case fatality rate amid the continued replacement of Omicron subvariants. At the same time, the decline in reported morbidity should be interpreted with caution because it may have been affected by changes in testing coverage, case ascertainment, and registration practices. The results confirm the need to maintain molecular epidemiological surveillance; expanded genomic monitoring, including whole-genome sequencing, is required for the detection and detailed characterization of new potentially significant variants.
