[Investigation of the Tsix gene regulatory region in vole Microtus rossiaemeridionalis]

The Tsix regulatory region was examined in vole Microtus rossiaemeridionalis. The minimal promoter region, three potential enhancer regulatory elements and one transcription suppressor element were identified. The enhancer regions contained potential binding sites of transcription activators, while in the region of putative silencer contained potential binding site of the ARP1 (NR2F2) protein. This protein can play the role of either activator or repressor depending on the promoter context.

[Electron microscopy as a diagnostic method in the epidemiological surveillance of poxvirus infections]

The materials of work lasting for 11 years and including the study of 3,425 samples collected at different periods after the eradication of smallpox from patients suspected for orthopoxvirus infection indicate high effectiveness of electron microscopy and especially immune electron microscopy as an integral part of diagnostic examination.

Monkey pox in humans: current results

The presented studies were performed at the WHO Collaboration Center for Smallpox in Moscow in the framework of the WHO monkey pox project. The authors recommend improved methods for rapid detection of orthopoxvirus antigen, namely passive haemagglutination (PHA) using dried stable red blood cells and ELISA in order to provide more rapid and efficient laboratory diagnosis under field conditions. Independent serologic diagnosis of monkey pox by ELISA-adsorption (ELISA-A) was proved of value for epidemiological studies and for detection of inapparent infections. The application range of the latter technique and its limitations were also determined.

[Laboratory-confirmed case of human infection with ratpox (cowpox)]

The present work describes a case of human disease resulting from the bite of a white rat and caused by a biological variant of cowpox virus. The isolates obtained from the sick man and the white rats which had been the source of this infection proved to be identical and did not differ from the biological variants of cowpox virus, isolated earlier from white rats and carnivorous animals of the family Felidae. Thus, the possibility of ratpox (cowpox) transmission from sick rodents to man was established.

Experimental infection of domestic cats by cowpox virus

Infection of young domestic cats by cowpox virus isolated from sick rodents (family Muridae) revealed their high susceptibility to the virus; a severe disease with 100% lethality developed after oral inoculation as well as upon skin scarification. The disease in dermally infected animals was accompanied by eruptions on the site of inoculation. High concentration of the virus was detected in lungs of animals infected by either of inoculation routes. The data testify the possible participation of domestic cats as intermediate hosts in the circulation of cowpox virus.

[The development and use of an immunoenzyme test system for detecting and the species identification of the monkey pox virus]

An enzyme immunoassay (EIA) system for the species-specific diagnosis of monkeypox, based on the use of monoclonal antibodies (McAb) to monkeypox virus, has been developed. Immunoglobulins, isolated from McAb-containing cultural and immune ascitic fluids, have been conjugated with horse-radish peroxidase and used as detector antibodies. For immunosorption, rabbit polyclonal antibodies to the vaccine virus have been used. The specificity and sensitivity of the EIA system thus obtained have been tested on animals and humans having monkeypox and confirmed by traditional diagnostic methods (the isolation of the virus on chick embryo chorioallantoic membranes and in cell culture).

[The biotype and genetic characteristics of an isolate of the cowpox virus causing infection in a child]

A virus, identified as cowpox virus by its biological properties and the results of the analysis of its DNA, was isolated from a sick 4-year-old child with a clinical picture of pox, though having had no contacts with known natural carriers of the causative agent of this infection. At the same time the isolated virus was found to differ from the reference strain, as well as from other isolates of vaccinia virus by some biological markers (and in particular by the structure of cytoplasmic inclusions of type A) and by the restriction profile of DNA. The Hind III maps indicating the location of restriction sites made it possible to localize the genome differences established in this study. The specific feature of this case was the previous close contact of the child with a mole which was probably the source of infection.

Novel B-Cell Epitopes of Non-Neutralizing Antibodies in the Receptor-Binding Domain of the SARS-CoV-2 S-Protein with Different Effects on the Severity of COVID-19

Antibodies against the receptor-binding domain of the SARS-CoV-2 spike protein (RBD S-protein) contribute significantly to the humoral immune response during coronavirus infection (COVID-19) and after vaccination. The main focus of the studies of the RBD epitope composition is usually concentrated on the epitopes recognized by the virus-neutralizing antibodies. The role of antibodies that bind to RBD but do not neutralize SARS-CoV-2 remains unclear. In this study, immunochemical properties of the two mouse monoclonal antibodies (mAbs), RS17 and S11, against the RBD were examined. Both mAbs exhibited high affinity to RBD, but they did not neutralize the virus. The epitopes of these mAbs were mapped using phage display: the epitope recognized by the mAb RS17 is located at the N-terminal site of RBD (348-SVYAVNRKRIS-358); the mAb S11 epitope is inside the receptor-binding motif of RBD (452-YRLFRKSN-459). Three groups of sera were tested for presence of antibodies competing with the non-neutralizing mAbs S11 and RS17: (i) sera from the vaccinated healthy volunteers without history of COVID-19; (ii) sera from the persons who had a mild form of COVID-19; (iii) sera from the persons who had severe COVID-19. Antibodies competing with the mAb S11 were found in each group of sera with equal frequency, whereas presence of the antibodies competing with the mAb RS17 in the sera was significantly more frequent in the group of sera obtained from the patients recovered from severe COVID-19 indicating that such antibodies are associated with the severity of COVID-19. In conclusion, despite the clear significance of anti-RBD antibodies in the effective immune response against SARS-CoV-2, it is important to analyze their virus-neutralizing activity and to confirm absence of the antibody-mediated enhancement of infection by the anti-RBD antibodies.