Targeting Extracellular Vesicles to Dendritic Cells and Macrophages.

Targeting protein therapeutics to specific cells and tissues is a major challenge in modern medicine. Improving the specificity of protein therapeutic delivery will significantly enhance efficiency in drug development. One of the promising tools for protein delivery is extracellular vesicles (EVs) that are enveloped by a complex lipid bilayer. EVs are secreted by almost all cell types and possess significant advantages: biocompatibility, stability, and the ability to penetrate the blood-brain barrier. Overexpression of the vesicular stomatitis virus protein G (VSV-G) was shown to promote EV formation by the producer cell. We have developed an EV-based system for targeted delivery of protein cargoes to antigen-presenting cells (APCs). In this study, we show that attachment of a recombinant llama nanobody α-CD206 to the N-terminus of a truncated VSV-G increases the selectivity of EV cargo delivery mainly to APCs. These results highlight the outstanding technological and biomedical potential of EV-based delivery systems for correcting the immune response in patients with autoimmune, viral, and oncological diseases.

Peculiarities of the Presentation of the Encephalitogenic MBP Peptide by HLA-DR Complexes Providing Protection and Predisposition to Multiple Sclerosis.

Predisposition to multiple sclerosis (MS), a chronic autoimmune disease of the central nervous system, is due to various factors. The genetic component is considered one of the most important factors. HLA class II genes contribute the most to the development of MS. The HLA-DRB1*15 allele group is considered one of the main genetic risk factors predisposing to MS. The group of HLA-DRB1*01 alleles was shown to have a protective effect against this disease in the Russian population. In this work, we compared the binding of the encephalitogenic fragment of the myelin basic protein (MBP) to two HLA-DR complexes that provide protection against and predisposition to MS: HLA-DR1 (HLA-DRB1*0101) and HLA-DR15 (HLA-DRB1*1501), respectively. We found that the myelin peptide MBP88-100 binds to HLA-DR1 at a rate almost an order of magnitude lower than the viral peptide of hemagglutinin (HA). The same was true for the binding of MBP85-97 to HLA-DR15 in comparison with viral pp65. The structure of the C-terminal part of the peptide plays a key role in the binding to HLA-DR1 for equally high-affinity N-terminal regions of the peptides. The IC50 of the myelin peptide MBP88-100 competing with viral HA for binding to HLA-DR1 is almost an order of magnitude higher than that of HA. As for HA, the same was also true for the binding of MBP85-97 to HLA-DR15 in comparison with viral pp65. Thus, autoantigenic MBP cannot compete with the viral peptide for binding to protective HLA-DR1. However, it is more competitive than viral peptide for HLA-DR15.

Production of Recombinant Protein Self-Assembly Nanocontainers in a Prokaryotic System.

We optimized a method for the preparation and purification of self-assembled protein nanocontainers EPN, the latest achievement in protein engineering. These nanocontainers are highly stable and provide the possibility of highly specific loading of a protein therapeutic drug. The described technique can be proposed as a tool for production of nanocontainers in a prokaryotic system. The obtained nanocontainers for the delivery of protein preparations can be used in the treatment of chronic, autoimmune, and oncological diseases.

[A new drug for serodiagnosis of listeriosis]. / Novyi preparat dlia serodiagnostiki listerioza.

Development and introduction into practical public health of new rapid methods for laboratory diagnosis of listeriosis, that will be characterized by a high sensitivity and specificity, is still a pressing problem. Listeriosis erythrocytic diagnosticum developed at the Omsk Research Institute for Natural Focal Infections permits the detection of species-specific antibodies in patients' sera and convalescents after this infection and is characterized by a sufficiently high diagnostic efficacy. Use of this agent appears to hold good promise in the diagnosis of listeriosis in the acute period of the disease, in retrospective diagnosis, and in screening of risk groups.

[The diagnostic effectiveness of an immunoenzyme test system for determining diphtheria toxin antigens in the blood serum in a clinical laboratory trial]. / Diagnosticheskaia éffektivnost' immunofermentnoi test-sistemy dlia opredeleniia antigenov difteriinogo toksina v syvorotke krovi pri kliniko-laboratornym ispytanii.

The data on the approbation of the diagnostic value of the enzyme immunoassay (EIA) system for the determination of diphtheria toxin in the blood sera of diphtheria patients and persons suspected for diphtheria are presented. The EIA system was prepared on the basis of F(ab)2 fractions of purified antidiphtheria antibodies. 240 serum samples from diphtheria and tonsillitis patients and from healthy persons were studied. Diphtheria toxin was determined in all patients with the toxic form of diphtheria and in 41.3% of patients with its localized forms. Blood was taken mainly of the first week of the disease. In healthy persons the results of EIA were negative. Thus, the trial of the assay system in a clinical laboratory showed its good diagnostic effectiveness. The use of this EIA system in medical practice is believed to be quite promising.

[Diagnostic meningococcal sera and their quality]. / Diagnosticheskie meningokokkovye syvorotki i ikh kachestvo.

The findings evidence that preparation of highly active specific meningococcal sera depends on the selection of production strains and reference cultures for the assessment of their conformity to technological requirements. Meningococcal cultures selection conditions may be unified if standard immune sera are developed, characterized by stable titres of antibodies to group capsule antigens. Employment of such sera will improve the quality of commercial agglutinating sera.