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Introduction: Varicella-Zoster virus (VZV) is a highly contagious alpha-herpes virus. The diagnosis of chickenpox remains a difficult task especially in cases of breakthrough chickenpox, so the development of reliable laboratory tests is necessary. The simplest and most sensitive serological test for detecting antibodies in human and animal sera is the passive hemagglutination reaction (PHAR)., The Aim: To develop of a simple, highly sensitive and specific serological tests for the detection of antibodies to VZV in human and animal blood sera., Materials and Methods: Human and animal cell cultures; various strains of VZV; human and animal immune sera; monoclonal antibody to VZV glycoprotein (GP) E. Formalin-treated erythrocytes of sheep, chickens and goats, sensibilised with GP of VZV from a virus-containing supernatant were used for PHAR., Results: Cell cultures with the maximum cytopathic effect at VZV infection were selected. A simple original method for obtaining virus-specific VZV GPs using lectins has been developed. Purified GPs were obtained by their elution from sheep erythrocytes after adsorption. The activity of VZV GP was confirmed in PHAR by an antibody diagnostic assay using formalin-treated sheep erythrocytes sensibilised using monoclonal antibodies to GP E of the "vOka" VZV strain (USA). Using GPs from different VZV strains, PHAR test and GP-based enzyme-linked immunosorbent assay (gpELISA) have been developed to detect antibodies in human and animal immune sera. These tests have high sensitivity, specificity and lack of cross-reactivity., Conclusion: A highly specific, sensitive and reproducible tests for the detection of antibodies to VZV have been developed.

Introduction: Polymerase proteins PB1 and PB2 determine the cold-adapted phenotype of the influenza virus A/Krasnodar/101/35/59 (H2N2), as was shown earlier., Objective: The development of the reporter construct to determine the activity of viral polymerase at 33 and 37 °C using the minigenome method., Materials and Methods: Co-transfection of Cos-1 cells with pHW2000 plasmids expressing viral polymerase proteins PB1, PB2, PA, NP (minigenome) and reporter construct., Results: Based on segment 8, two reporter constructs were created that contain a direct or inverted NS1-GFP-NS2 sequence for the expression of NS2 and NS1 proteins translationally fused with green fluorescent protein (GFP), which allowed the evaluation the transcriptional and/or replicative activity of viral polymerase., Conclusion: Polymerase of virus A/Krasnodar/101/35/59 (H2N2) has higher replicative and transcriptional activity at 33 °C than at 37 °C. Its transcriptional activity is more temperature-dependent than its replicative activity. The replicative and transcriptional activity of polymerase A/Puerto Rico/8/34 virus (H1N1, Mount Sinai variant) have no significant differences and do not depend on temperature.

Influenza A virus is a serious human pathogen that assembles enveloped virions on the plasma membrane of the host cell. The pleiomorphic morphology of influenza A virus, represented by spherical, elongated, or filamentous particles, is important for the spread of the virus in nature. Using fixative protocols for sample preparation and negative staining electron microscopy, we found that the recombinant A/WSN/33 (H1N1) (rWSN) virus, a strain considered to be strictly spherical, may produce filamentous particles when amplified in the allantoic cavity of chicken embryos. In contrast, the laboratory WSN strain and the rWSN virus amplified in Madin-Darby canine kidney cells exhibited a spherical morphology. Next-generation sequencing (NGS) suggested a rare Ser126Cys substitution in the M1 protein of rWSN, which was confirmed by the mass spectrometric analysis. No structurally relevant substitutions were found by NGS in other proteins of rWSN. Bioinformatics algorithms predicted a neutral structural effect of the Ser126Cys mutation. The mrWSN_M1_126S virus generated after the introduction of the reverse Cys126Ser substitution exhibited a similar host-dependent partially filamentous phenotype. We hypothesize that a shortage of some as-yet-undefined cellular components involved in virion budding and membrane scission may result in the appearance of filamentous particles in the case of usually "nonfilamentous" virus strains.