Vol 70, No 4 (2025)

The review examines issues related to occult hepatitis B virus infection (OBI), which occurs at a late stage of chronic hepatitis B (CHB) after HBsAg clearance. In clinical practice, OBI is detected by the absence of HBsAg and the presence of antibodies to HBcAg in the blood serum and is often referred to as «past» or «resolved» hepatitis B. However, hepatitis B virus (HBV) DNA remains in liver cells, is poorly detected by routine diagnostic methods, and cannot be removed by existing therapies. Data on the prevalence of OBI vary, but it is found in all regions of the world, much more often in regions with a high prevalence of HBV. Data on the association of OBI with fibrosis, cirrhosis and hepatocellular carcinoma (HCC) have been obtained. It has been established that OBI is associated with an increased risk of HBV reactivation in patients with infections with other viruses, as well as in cancer patients whose treatment includes immunosuppressive therapy. HBV reactivation leads to severe consequences and, in the absence of treatment, death of patients. It can be concluded that to achieve the goal set by WHO for the eradication of viral hepatitis by 2030, it is necessary to solve the problem of OBI. In order to make this possible, it is essential to create new, more sensitive and informative diagnostic tests, effective methods of HBV DNA elimination, and to investigate the mechanisms of OBI development in more depth.

Introduction. Vpr is a multifunctional auxiliary HIV-1 protein. Oligomerisation is a prerequisite for the entry of Vpr into the virion and its subsequent participation in the early stages of HIV-infection. To date, natural amino acid substitutions in Vpr associated with disease progression were identified; the possibility of creating therapeutics based on Vpr is being considered.

The aim of the study is to investigate Vpr features in the most common genetic variants of HIV-1 circulating in the Moscow region in 2019–2020.

Materials and methods. HIV-1 samples obtained from 231 patients of the AIDS Prevention and Control Center in the period 2019–2020 were studied according to the scheme: proviral DNA extraction, amplification of the vpr gene, sequencing, and data analysis. Consensus Vpr sequences of the most common genetic variants in Russia and their spatial structures, variability of Vpr variants of HIV-1 sub-subtype A6 in patients with different stages of the disease were studied.

Results. Features of Vpr protein in different genetic variants of HIV-1 could influence the formation of their oligomeric forms. No sites with statistically significant differences in the frequency of amino acid substitutions were identified in patients with different stages of disease.

Conclusion. Vpr protein of HIV-1 genetic variants circulating in Russia may have differences in functional properties. Vpr-A6 variants had low variability in patients with different stages of the disease, and therefore Vpr-A6 can be considered as a target for the development of therapeutic agents.

Introduction. Severe influenza is characterized by damage and morphofunctional changes of the endothelium of blood vessels, which contributes to the development of hemorrhagic syndrome and can cause endothelial dysfunction. To optimize the pathogenetic therapy of influenza infection, a screening of medications with endothelial protective properties was carried out.

Aim. The aim of the study was to evaluate the endothelial protective properties of sacubitril/valsartan and drotaverine in influenza A(H1N1)pdm09 virus infection.

Materials and methods. The study was conducted on Wistar rats, which received sacubitril/valsartan and drotaverine (in treatment and prophylactic regimen) followed by intransal infection with influenza A/Saint-Petersburg/48/16 (H1N1)pdm09 virus. Rats without drug administration were included in the control group; rats received no medications followed by influenza virus infection – in challenge control group. The virus infectious activity was determined in pulmonary and mesenteric tissues. Vascular endothelium damage in lungs was assessed by three parameters (desquamation, morphological and dystrophic changes). Endothelial nitric oxide synthase (eNOS) expression level in endothelium of mesenteric blood vessels was determined as well as mesenteric arteries vasomotor activity.

Results. Drotaverine reduces the severity of histopathological changes in the pulmonary vascular endothelium; increases the maximal response of mesenteric blood vessels to acetylcholine compared to the infection control group; normalizes eNOS expression levels. Sacubitril/valsartan reduces the severity of desquamation in the pulmonary vascular endothelium; normalizes the response of mesenteric blood vessels to acetylcholine, while eNOS expression is decreased.

Conclusions. Drotaverine possesses more significant endothelial protective properties than sacubitril/valsartan when used in a treatment and prophylactic regimen in rats infected with influenza A(H1N1)pdm09 virus.

Introduction. Pharmacopoeial standard of activity, specificity and necrotic activity is used in testing of for smallpox vaccines. As a part of standard certification, an opportunity of using Pharmacopoeial standard for smallpox vaccine on new cell culture method (in vitro) for testing a new generation of smallpox vaccines was also defined.

The aim – certification of the Pharmacopoeial standard for smallpox vaccine to the main certified characteristics and defining an opportunity for using Pharmacopoeial standard for smallpox vaccine on new cell culture method (in vitro).

Materials and methods. Pharmacopoeial standard for smallpox vaccine (FSO 3.2.00113, series 130406) and pharmacopoeial biological methods described in the State Pharmacopoeia of the Russian Federation (S.Ph), the monograph 3.3.1.0033.15 Smallpox vaccine live were used in the study. For cell culture method, the technique from State Research Centre of Virology and Biotechnology «Vector» of the Federal Service for Surveillance in Consumer Rights Protection and Human Well-being, Novosibirsk Region, Koltsovo, Russian Federation was used. Statistical data were evaluated using Microsoft Excel software.

Results. The Pharmacopoeial standard for smallpox vaccine (FSO 3.2.00113) was certified. The possibility of using a new method of determining specific activity, specificity (identification) using the culture method was confirmed.

Conclusion. Along with the confirmation of certified characteristics, the possibility of using a new methodology for determining specific activity, specificity (identification) using the culture method was confirmed, and the main acceptance criteria were determined.

Introduction. Highly pathogenic for humans orthopoxviruses (OPV) – Variola virus (VARV) and Monkeypox virus (MPXV) can cause systemic diseases characterized by high contagiousness and often leading to death. In previous publications (https://doi.org/10.3390/v14112580), we reported on the development of a sensitive, rapid and easy-to-use immunochemical test potentially suitable for use in the infection foci and in laboratory conditions with a high level of biosecurity. The prototype of the diagnostic kit was tested on non-pathogenic and low-pathogenic for humans OPV and specifically detected them with a sensitivity within the range of 10³ to 10⁴ PFU/mL.

The aim of this work was to evaluate the sensitivity of this assay in detecting highly pathogenic for humans MPXV and VARV, as well as the applicability of the assay in a laboratory with a high level of biosafety (BSL-4).

Materials and methods. The efficiency of virus detection in cryolysates of CV-1 cell culture samples infected with VARV and MPXV was assessed using a one-step dot immunoassay method in a laboratory with biosafety level BSL-4.

Results. It was shown that the one-step dot assay allows detection of MPXV at a concentration of 2.5 × 10³ PFU/mL, and VARV at a concentration of 1.0 × 10⁴ PFU/mL. It was noted that vapors from disinfectants (hydrogen peroxide/formaldehyde) applied in biosafety cabinet decontamination may interfere with assay performance and affect result interpretation.

Conclusion. The one-step dot immunoassay can be performed in a BSL-4 laboratory. When limiting the contact of the detecting system with formaldehyde vapors, the sensitivity of the test for detection of VARV and MPXV falls within the previously declared range of 10³–10⁴ PFU/mL.