Introduction. Enterovirus (nonpolio) infection is widespread all over the world, registered as sporadic cases and large-scale outbreaks and can cause severe lesions such as serous meningitis. Epidemiological studies have shown that enterovirus (Picornaviridae; Enterovirus) variant Echovirus 30 (E30) is the most frequently detected variant in patients with enterovirus meningitis in the Russian Federation. However, no vaccines to prevent the disease caused by this pathogen have been developed so far. One of the promising modern trends in terms of creating vaccine preparations is the use of virus-like particles (VLPs), including chimeric ones containing the biological structures of viruses belonging to different species. The aim of this work was to obtain norovirus (Caliciviridae; Norovirus) VLPs displaying enterovirus Echovirus E30 full-length VP1 on the surface. Material and methods. The nucleotide sequences of VP1 protein of norovirus genotype GII.4 and VP1 E30 of genotype h circulating in Russia were used. The SN-VP1E30 protein was constructed, in which the shell (S) and the hinge regions of the norovirus VP1 are fused into one molecule with the full-length VP1 of the E30 virus. The protein was expressed in E. coli, purified using affinity chromatography, and characterized by polyacrylamide gel electrophoresis (PAGE) and immunoblotting. VLPs were visualized by electron microscopy. Results. The S N-VP1E30 protein expressed in E. coli as insoluble form, so the conditions for SN-VP1E30 solublisation were defined. Sucrose has been shown to significantly increase the efficiency of renaturation. Electrophoretic mobility comparison of denatured and non-denatured SN-VP1E30 demonstrated that most monomers form high molecular weight compounds. Electron microscopy showed that renatured SN-VP1E30 spontaneously forms empty virus-like particles about 50 nm in diameter. Conclusion. Chimeric protein SN-VP1E30 self-assemble into VLPs displaying the VP1 protein of E30 variant that is highly prevalent in Russia. Further immunological research is necessary to characterize VLPs potential for development of the vaccine for enteroviral meningitis prevention.

Introduction. Enterovirus (nonpolio) infection is widespread all over the world, registered as sporadic cases and large-scale outbreaks and can cause severe lesions such as serous meningitis. Epidemiological studies have shown that enterovirus (Picornaviridae; Enterovirus) variant Echovirus 30 (E30) is the most frequently detected variant in patients with enterovirus meningitis in the Russian Federation. However, no vaccines to prevent the disease caused by this pathogen have been developed so far. One of the promising modern trends in terms of creating vaccine preparations is the use of virus-like particles (VLPs), including chimeric ones containing the biological structures of viruses belonging to different species.The aim of this work was to obtain norovirus (Caliciviridae; Norovirus) VLPs displaying enterovirus Echovirus E30 full-length VP1 on the surface.Material and methods. The nucleotide sequences of VP1 protein of norovirus genotype GII.4 and VP1 E30 of genotype h circulating in Russia were used. The SN-VP1E30 protein was constructed, in which the shell (S) and the hinge regions of the norovirus VP1 are fused into one molecule with the full-length VP1 of the E30 virus. The protein was expressed in E. coli, purified using affinity chromatography, and characterized by polyacrylamide gel electrophoresis (PAGE) and immunoblotting. VLPs were visualized by electron microscopy.Results. The S N-VP1E30 protein expressed in E. coli as insoluble form, so the conditions for SN-VP1E30 solublisation were defined. Sucrose has been shown to significantly increase the efficiency of renaturation. Electrophoretic mobility comparison of denatured and non-denatured SN-VP1E30 demonstrated that most monomers form high molecular weight compounds. Electron microscopy showed that renatured SN-VP1E30 spontaneously forms empty virus-like particles about 50 nm in diameter.Conclusion. Chimeric protein SN-VP1E30 self-assemble into VLPs displaying the VP1 protein of E30 variant that is highly prevalent in Russia. Further immunological research is necessary to characterize VLPs potential for development of the vaccine for enteroviral meningitis prevention.

The virologists’ attention to bats (Сhiroptera) changed in the late 20th century as the concept of emerging infections grew in popularity. Since the beginning of the COVID-19 pandemic, the number of publications on bat viruses has increased profoundly. History of the problem; biodiversity of Chiroptera and related viruses; medical and veterinary significance of some viral genera and subgenera (Lyssavirus, Henipavirus, Marburgvirus, Ebolavirus, Sarbecovirus, Merbecovirus), as well as problems of bat protection, are addressed in a concise form. Literature search was carried out in electronic databases, mainly for the period of 2000–2021. Publications in Russian that are poorly represented in English-language reviews are also included. The purpose of the review is to substantiate the importance of an interdisciplinary approach in the context of increased interest in the study of viral infections in bats. This review was written for researchers who have not previously dealt with this problem. Since the beginning of this century, the number of known virus species associated with bats has increased by an order of magnitude (>200). The families Rhabdoviridae, Coronaviridae, Paramyxoviridae are in the first ranks according to the number of findings, and the highest diversity of viruses has been established for the families Vespertilionidae, Pteropodidae, Molossidae. Interdisciplinary cooperation positively influences the efficiency, biological safety and practical significance of the ongoing research. The best results were achieved by multidisciplinary teams with good cross-training in several specialties. Many papers emphasize the need to balance health and conservation interests. The analysis of scientific publications indicates a change in research approaches in this area: from collecting individual facts within the framework of narrow specialties to a comprehensive assessment of new knowledge from ecological, evolutionary and socio-economic positions. Results of the research emphasize the need to maintain complex approaches addressing public health needs and environmental protection. The importance of bat-borne viral infections determines the necessity for correction and interdepartmental coordination of scientific research and surveillance of wildlife zoonoses in the Russian Federation.

Introduction. Enterovirus (nonpolio) infection is widespread all over the world, registered as sporadic cases and large-scale outbreaks and can cause severe lesions such as serous meningitis. Epidemiological studies have shown that enterovirus (Picornaviridae; Enterovirus) variant Echovirus 30 (E30) is the most frequently detected variant in patients with enterovirus meningitis in the Russian Federation. However, no vaccines to prevent the disease caused by this pathogen have been developed so far. One of the promising modern trends in terms of creating vaccine preparations is the use of virus-like particles (VLPs), including chimeric ones containing the biological structures of viruses belonging to different species. The aim of this work was to obtain norovirus (Caliciviridae; Norovirus) VLPs displaying enterovirus Echovirus E30 full-length VP1 on the surface. Material and methods. The nucleotide sequences of VP1 protein of norovirus genotype GII.4 and VP1 E30 of genotype h circulating in Russia were used. The S N -VP1 E30 protein was constructed, in which the shell (S) and the hinge regions of the norovirus VP1 are fused into one molecule with the full-length VP1 of the E30 virus. The protein was expressed in E. coli, purified using affinity chromatography, and characterized by polyacrylamide gel electrophoresis (PAGE) and immunoblotting. VLPs were visualized by electron microscopy. Results. The S N -VP1 E30 protein expressed in E. coli as insoluble form, so the conditions for S N -VP1 E30 solublisation were defined. Sucrose has been shown to significantly increase the efficiency of renaturation. Electrophoretic mobility comparison of denatured and non-denatured S N -VP1 E30 demonstrated that most monomers form high molecular weight compounds. Electron microscopy showed that renatured S N -VP1 E30 spontaneously forms empty virus-like particles about 50 nm in diameter. Conclusion. Chimeric protein S N -VP1 E30 self-assemble into VLPs displaying the VP1 protein of E30 variant that is highly prevalent in Russia. Further immunological research is necessary to characterize VLPs potential for development of the vaccine for enteroviral meningitis prevention.

Spatial organization and conformational changes of antibodies may significantly affect their biological functions. We assessed the effect of mutual organization of the two VHH domains within bispecific antibodies recognizing human TNF and the surface molecules of murine myeloid cells (F4/80 or CD11b) on TNF retention and inhibition. TNF‐neutralizing properties in vitro and in vivo of MYSTI‐2 and MYSTI‐3 antibodies were compared with new variants with interchanged VHH domains and different linker sequences. The most effective structure of MYSTI‐2 and MYSTI‐3 proteins required the Ser/Gly‐containing ‘superflexible’ linker. The orientation of the modules was crucial for the activity of the proteins, but not for MYSTI‐3 with the Pro/Gln‐containing ‘semi‐rigid’ linker. Our results may contribute toward the development of more effective drug prototypes.

Известно, что белок норовируса VP1 способен самостоятельно собираться в вирусоподобные частицы (ВПЧ), на которые развивается достаточно сильный иммунный ответ. Нами получен рекомбинантный VP1 эпидемического варианта норовируса генотипа GII.4, доминировавшего на территории Нижегородской области в 2018 г. Показана способность VP1 к самосборке, его безопасность и иммуногенность. ВПЧ на основе VP1 норовируса использованы в качестве молекулярной платформы для разработки вакцины против коронавирусной инфекции. Для этого проведена замена части белка VP1, экспонированной на поверхности ВПЧ, на аминокислотную последовательность SARS-CoV-2, кодирующую сайты связывания с рецепторами (RBD). Для увеличения растворимости и корректного фолдинга N-концевая часть рекомбинантной химеры VP1 норовируса с RBD SARS-CoV-2 слита с периплазматическим мальтозосвязывающим белком E.coli с включением сайта для специфичного гидролиза. Проведена оптимизация экспрессии, растворения и очистки слитого белка VP1 норовируса с RBD SARS-CoV-2. Полученная химерная структура может быть использована в составе вакцины для профилактики COVID-19, применимой для интраназальной вакцинации.

— The aim of this work was to evaluate novel three-domain antibodies consisting of two domains specific for human tumor necrosis factor (hTNF), and of the third domain responsible for binding to myeloid cells. The additional hTNF-binding domain should serve to increase the biological activity of new antibodies. Capacity of these proteins to bind hTNF on the macrophage surface and to neutralize its biological activity in vitro was assessed.

Systemic TNF neutralization can be used as a therapy for several autoimmune diseases. To evaluate the effects of cell type-restricted TNF blockade, we previously generated bispecific antibodies that can limit TNF secretion by myeloid cells (myeloid cell-specific TNF inhibitors or MYSTIs). In this study several such variable domain (VH) of a camelid heavy-chain only antibody-based TNF inhibitors were compared in relevant experimental models, both in vitro and in vivo. Pretreatment with MYSTI-2, containing the anti-F4/80 module, can restrict the release of human TNF (hTNF) from LPS-activated bone marrow-derived macrophage (BMDM) cultures of humanized TNF knock-in (mice; hTNFKI) more effectively than MYSTI-3, containing the anti-CD11b module. MYSTI-2 was also superior to MYSTI-3 in providing in vivo protection in acute toxicity model. Finally, MYSTI-2 was at least as effective as Infliximab in preventing collagen antibody-induced arthritis. This study demonstrates that a 33 kDa bispecific mini-antibody that specifically restricts TNF secretion by macrophages is efficient for amelioration of experimental arthritis.

In spite of successful therapeutic neutralization of proinflammatory cytokines in several autoimmune diseases, such therapy is not entirely free of side effects. The main reason relates to the fact that cytokine signaling may have protective components that need to be spared. Several approaches to achieve a less damaging cytokine inhibition are being explored. In our experimental studies we are using bispecific reagents based on VHH-modules from the heavy-chain-only antibodies to limit bioavailability of TNF and IL-6 produced by myeloid cells. After evaluation of their properties in vitro and in vivo we argue that these types of reagents may have an advantage over systemic blockers.

Upregulation of the expression of tumor necrosis factor (TNF-α, TNF) has a significant role in the development of autoimmune diseases. The fluorescent antibodies binding TNF may be used for personalized therapy of TNF-dependent diseases as a tool to predict the response to anti-TNF treatment. We generated recombinant fluorescent proteins consisting of the anti-TNF module based on the variable heavy chain (VHH) of camelid antibodies fused with the far-red fluorescent protein Katushka (Kat). Two types of anti-TNF VHH were developed: one (BTN-Kat) that was bound both human or mouse TNF, but did not neutralize their activity, and a second (ITN-Kat) that was binding and neutralizing human TNF. BTN-Kat does not interfere with TNF biological functions and can be used for whole-body imaging. ITN-Kat can be evaluated in humanized mice or in cells isolated from humanized mice. It is able to block human TNF (hTNF) activities both in vitro and in vivo and may be considered as a prototype of a theranostic agent for autoimmune diseases.

Bispecific antibodies capable of simultaneously binding two targets have been studied for many years with a view to their implementation in clinical practice. Unique biological and pharmacological properties, as well as the diversity of their formats, make it possible to consider bispecific antibodies as promising agents for use in various procedures: from visualization of intracellular processes to targeted anticancer therapy. Bispecific antibodies help to determine more precisely the therapeutic target, thereby increasing the efficiency of therapy and reducing the probability of side effects. The present review describes the main formats of bispecific antibodies, methods for their generation, and possibilities for practical application.

Binding of native bacterial protein SlyD to metal affinity matrices remains a major problem in affinity purification of His-tagged recombinant proteins from Escherichia coli cells. In this study, four novel E. coli strains that lack the expression of SlyD/SlyX, were engineered using λ-red mediated chromosomal deletion. The resultant mutant E. coli strains allow us to obtain SlyD-free proteins immediately after metal affinity chromatography, and eliminate additional purification processes. As a model protein, bispecific antibodies composed of anti-F4/80 VHH module and anti-TNF VHH module (MYSTI-2) were used. Using this protein we have shown that the SlyD/SlyX-deficient E. coli strains allow us to obtain a fully functional protein.

Proinflammatory cytokines, such as TNF, IL-6, and IL-1, play pathogenic roles in multiple diseases and are attractive targets for biologic drugs. Because proinflammatory cytokines possess non-redundant protective and immunoregulatory functions, their systemic neutralization carries the potential for unwanted side effects. Therefore, next-generation anti-cytokine therapies would seek to selectively neutralize pathogenic cytokine signaling, leaving normal function intact. Fortunately, the biology of proinflammatory cytokines provides several such opportunities. Here, we discuss various applications of bispecific antibodies targeting cytokines with specific focus on selective TNF neutralization targeted directly to the surface of specific populations of monocytes and macrophages. These bispecific antibodies combine an anti-TNF VHH with VHHs or scFvs directed against abundant surface molecules on myeloid cells and serve to limit the bioavailability of TNF produced by these cells. Such reagents may become prototypes of a novel class of anti-cytokine biologics.

Overexpression of TNF contributes to pathogenesis of multiple autoimmune diseases, accounting for a remarkable success of anti-TNF therapy. TNF is produced by a variety of cell types, and it can play either a beneficial or a deleterious role. In particular, in autoimmunity pathogenic TNF may be derived from restricted cellular sources. In this study we evaluated the feasibility of cell-type-restricted TNF inhibition in vivo. To this end, we engineered MYSTI (Myeloid-Specific TNF Inhibitor)--a recombinant bispecific antibody that binds to the F4/80 surface molecule on myeloid cells and to human TNF (hTNF). In macrophage cultures derived from TNF humanized mice MYSTI could capture the secreted hTNF, limiting its bioavailability. Additionally, as evaluated in TNF humanized mice, MYSTI was superior to an otherwise analogous systemic TNF inhibitor in protecting mice from lethal LPS/D-Galactosamine-induced hepatotoxicity. Our results suggest a novel and more specific approach to inhibiting TNF in pathologies primarily driven by macrophage-derived TNF.

Abstract Proinflammatory cytokines, in particular IL-6 and TNF, are crucial factors in the development of autoimmune immune response. Their systemic inhibition has been successfully used as a therapy of multiple autoimmune and inflammatory diseases. However, recent data from murine genetic models suggest that the cellular source of proinflammatory cytokines may significantly affect their biological effects. Cytokines derived from particular cellular sources may be pathogenic while the same cytokine produced by other cell may play a protective role. Thus, systemic cytokine inhibition may be far from the optimal therapeutic approach. To independently confirm these findings and to evaluate potentially more effective therapeutic approaches we are developing bispecific antibodies, which may serve as inhibitors of proinfllammatory cytokines targeted to specific cells. Using myeloid-specific TNF inhibitor we have demonstrated that limiting TNF inhibition to macrophages and monocytes results in superior neutralization activity in the TNF-induced hepatotoxicity model. This approach could lower both the required dose and potentially the incidence of side effects. Currently we are developing the similar approach for IL-6. Our bispecific reagents are based on two different VhH antibodies, thus we immunized the lama with recombinant IL-6 and selected high affinity single-domain antibodies by phage display. Funding: Russian Scientific Fund grant 14-25-00160 (anti-IL6 antibodies), RFBR grant 14-04-01656 (anti-TNF).

Zbed4, a member of the BED subclass of Zinc-finger proteins, is expressed in cone photoreceptors and glial Müller cells of human retina whereas it is only present in Müller cells of mouse retina. To characterize structural and functional properties of Zbed4, enough amounts of purified protein were needed. Thus, recombinant Zbed4 was expressed in E. coli and its refolding conditions optimized for the production of homogenous and functionally active protein. Zbed4’s secondary structure, determined by circular dichroism spectroscopy, showed that this protein contains 32% α-helices, 18% β-sheets, 20% turns and 30% unordered structures. CASTing was used to identify the target sites of Zbed4 in DNA. The majority of the DNA fragments obtained contained poly-Gs and some of them had, in addition, the core signature of GC boxes; a few clones had only GC-boxes. With electrophoretic mobility shift assays we demonstrated that Zbed4 binds both not only to DNA and but also to RNA oligonucleotides with very high affinity, interacting with poly-G tracts that have a minimum of 5 Gs; its binding to and GC-box consensus sequences. However, the latter binding depends on the GC-box flanking nucleotides. We also found that Zbed4 interacts in Y79 retinoblastoma cells with nuclear and cytoplasmic proteins Scaffold Attachment Factor B1 (SAFB1), estrogen receptor alpha (ERα), and cellular myosin 9 (MYH9), as shown with immunoprecipitation and mass spectrometry studies as well as gel overlay assays. In addition, immunostaining corroborated the co-localization of Zbed4 with these proteins. Most importantly, in vitro experiments using constructs containing promoters of genes directing expression of the luciferase gene, showed that Zbed4 transactivates the transcription of those promoters with poly-G tracts.

An attenuated Australian strain of West Nile virus (WNV), Kunjin (KUN), shares ~98% amino acid homology with the pathogenic New York 99 NY99 strain (NY99). To investigate the viral factors involved in NY99 virulence we generated an infectious cDNA clone of the WNV NY99 4132 isolate from which virus was recovered and was shown to be indistinguishable from the parental isolate. We then introduced the regions of the NY99 non-structural (NS) proteins and/or untranslated regions (UTRs) into the KUN backbone. Chimeric KUN viruses containing NY99 5′UTR and the parts of NS coding region were more virulent in mice than parental KUN virus. Chimeric NY99 viruses, containing KUN NS2A protein with alanine 30 to proline substitution were significantly less cytopathic in cells and less virulent in mice. Our results identify the 5′UTR and NS proteins as WNV virulence determinants and confirm a role for the NS2A in WNV cytopathicity and virulence.