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Goltsev, A., Fuller, B., Bondarovich, M., Babenko, N., Gaevska, Y., Buriak, I., Dubrava, T. ., Yampolska, K., Lutsenko, O., & Ostankov, M. (2020). COVID–19 – потенційна мішень для кріобіології і кріомедицини. Проблеми кріобіології і кріомедицини, 30(2), 107–131. https://doi.org/10.15407/cryo30.02.107 У огляді представлено дані щодо імунопатогенезу COVІD-19 і підходів до його профілактики та лікування. Низька ефективність противірусних засобів обумовлена здатністю вірусу SARS-CoV2 до зміни власних структурних і функціональних характеристик. Існуючі стратегії лікування COVІD-19 сфокусовані на застосуванні лікувальних засобів прямої противірусної дії, модуляції вродженої імунної відповіді, пригніченні «цитокінового шторму» та застосуванні плазми реконвалесцентів. Дизрегуляція взаємодії систем вродженого та адаптивного імунітету обумовлює запуск аутоімунного процесу в організмі вірусоносія, що потребує застосування альтернативних підходів до профілактики таких захворювань із використанням кріобіологічних технологій. Наведено результати вивчення імунобіологічної активності кріоконсервованого лейкоконцентрату кордової крові людини (кЛККЛ) і його компонентів за превентивного інтраназального введення. Ефективність застосування кЛККЛ пов’язана з можливістю перепрограмування генів, відповідальних за реалізацію імунних відповідей організму та індукцію «тренованого» імунітету. Така модифікація стану імунної системи може бути найбільш перспективною у забезпеченні захисту організму від вірусів, зокрема COVІD-19. __________________________________________________________________________________________ The review presents data on immune pathogenesis of COVID-19 and approaches to its prevention and treatment. The low effectiveness of antiviral drugs is caused by the ability of SARS-CoV2 virus to change its own structure and functions. Existing treatment strategies of COVID-19 are focused on applying the direct antiviral therapies, modulation of innate immune response, "cytokine storm" suppression and use of convalescent plasma. Deregulated interaction between innate and adaptive immune systems determines the start of autoimmune process in the virus carrier body, that requires the use of alternative ways to prevent such diseases using cryobiological technologies. The results of studying the immune biological activity of cryopreserved human cord blood leukoconcentrate (cHCBL) and its components by preventive intranasal administration have been presented. The effectiveness of cHCBL is related to the possible reprogramming of the genes responsible for the implementation of the body's immune responses and induction of the "trained" immunity. Such a modification of the immune system state can be the most promising in protecting the body against viruses, in particular COVID-19.

Reactivation of latent cytomegalovirus (CMV) endangers the therapeutic success of hematopoietic cell transplantation (HCT) in tumor patients due to cytopathogenic virus spread that leads to organ manifestations of CMV disease, to interstitial pneumonia in particular. In cases of virus variants that are refractory to standard antiviral pharmacotherapy, immunotherapy by adoptive cell transfer (ACT) of virus-specific CD8+ T cells is the last resort to bridge the “protection gap” between hematoablative conditioning for HCT and endogenous reconstitution of antiviral immunity. We have used the well-established mouse model of CD8+ T-cell immunotherapy by ACT in a setting of experimental HCT and murine CMV (mCMV) infection to pursue the concept of improving the efficacy of ACT by therapeutic vaccination (TherVac) post-HCT. TherVac aims at restimulation and expansion of limited numbers of transferred antiviral CD8+ T cells within the recipient. Syngeneic HCT was performed with C57BL/6 mice as donors and recipients. Recipients were infected with recombinant mCMV (mCMV-SIINFEKL) that expresses antigenic peptide SIINFEKL presented to CD8+ T cells by the MHC class-I molecule Kb. ACT was performed with transgenic OT-I CD8+ T cells expressing a T-cell receptor specific for SIINFEKL-Kb. Recombinant human CMV dense bodies (DB-SIINFEKL), engineered to contain SIINFEKL within tegument protein pUL83/pp65, served for vaccination. DBs were chosen as they represent non-infectious, enveloped, and thus fusion-competent subviral particles capable of activating dendritic cells and delivering antigens directly into the cytosol for processing and presentation in the MHC class-I pathway. One set of our experiments documents the power of vaccination with DBs in protecting the immunocompetent host against a challenge infection. A further set of experiments revealed a significant improvement of antiviral control in HCT recipients by combining ACT with TherVac. In both settings, the benefit from vaccination with DBs proved to be strictly epitope-specific. The capacity to protect was lost when DBs included the peptide sequence SIINFEKA lacking immunogenicity and antigenicity due to C-terminal residue point mutation L8A, which prevents efficient proteasomal peptide processing and binding to Kb. Our preclinical research data thus provide an argument for using pre-emptive TherVac to enhance antiviral protection by ACT in HCT recipients with diagnosed CMV reactivation.

Cytomegaloviruses (CMVs) are controlled by innate and adaptive immune responses in an immunocompetent host while causing multiple organ diseases in an immunocompromised host. A risk group of high clinical relevance comprises transiently immunocompromised recipients of hematopoietic cell transplantation (HCT) in the “window of risk” between eradicative therapy of hematopoietic malignancies and complete reconstitution of the immune system. Cellular immunotherapy by adoptive transfer of CMV-specific CD8 T cells is an option to prevent CMV disease by controlling a primary or reactivated infection. While experimental models have revealed a viral epitope-specific antiviral function of cognate CD8 T cells, the site at which control is exerted remained unidentified. The observation that remarkably few transferred cells protect all organs may indicate an early blockade of virus dissemination from a primary site of productive infection to various target organs. Alternatively, it could indicate clonal expansion of a few transferred CD8 T cells for preventing intra-tissue virus spread after successful initial organ colonization. Our data in the mouse model of murine CMV infection provide evidence in support of the second hypothesis. We show that transferred cells vigorously proliferate to prevent virus spread, and thus viral histopathology, by confining and eventually resolving tissue infection within nodular inflammatory foci.

Cytomegaloviruses (CMVs) are host species-specific and have adapted to their respective mammalian hosts during co-evolution. Host-adaptation is reflected by “private genes” that have specialized in mediating virus-host interplay and have no sequence homologs in other CMV species, although biological convergence has led to analogous protein functions. They are mostly organized in gene families evolved by gene duplications and subsequent mutations. The host immune response to infection, both the innate and the adaptive immune response, is a driver of viral evolution, resulting in the acquisition of viral immune evasion proteins encoded by private gene families. As the analysis of the medically relevant human cytomegalovirus by clinical investigation in the infected human host cannot make use of designed virus and host mutagenesis, the mouse model based on murine cytomegalovirus (mCMV) has become a versatile animal model to study basic principles of in vivo virus-host interplay. Focusing on the immune evasion of the adaptive immune response by CD8+ T cells, we review here what is known about proteins of two private gene families of mCMV, the m02 and the m145 families, specifically the role of m04, m06, and m152 in viral antigen presentation during acute and latent infection.

Interferons are a family of proteins that are released by a variety of cells in response to infections caused by viruses. Currently, we distinguish three types of interferons. They are classified based on the nucleotide sequence, interaction with specific receptors, chromosomal location, structure and physicochemical properties. The following interferons are classified as type I: α, β, ω, κ, ε, ζ, τ, δ, ν. They are recognized and bound by a receptor formed by two peptides, IFN-αR1 and IFN-αR2. Representative of type II interferons is interferon-γ. It binds to a receptor composed of chains IFNGR-1 and IFNGR-2. The recently classified type III interferons comprise IFN-λ1, IFN-λ2, and IFN-λ3. They act on receptors formed by λR1 IFN-and IL-10R2 subunits. A high level of antiviral protection is achieved by IFN-α, IFN-β and IFN-λ. Antiviral activity of interferons is based on the induction and regulation of innate and acquired immune mechanisms. By binding to transmembrane receptors, IFN interacts with target cells mainly by activating the JAK/STAT, but also other signaling pathways. This leads to induction and activation of many antiviral agents, such as protein kinase RNA-activated (PKR), ribonuclease 2-5A pathway, and Mx proteins, as well as numerous apoptotic pathways. As a result of the protective effect of interferons, the virus binding to cells and viral particles penetration into cells is stopped, and the release of the nucleocapsid from an envelope is suppressed. Disruption of transcription and translation processes of the structural proteins prevents the formation of virions or budding of viruses, and as a result degradation of the viral mRNA; the started processes inhibit the chain synthesis of viral proteins and therefore further stimulate the immune system cells.

Mosquito-borne viruses such as dengue, West Nile and chikungunya viruses cause significant morbidity and mortality in human populations. Since current methods are not sufficient to control disease occurrence, novel methods to control transmission of arboviruses would be beneficial. Recent studies have shown that virus infection and transmission in insects can be impeded by co-infection with the bacterium Wolbachia pipientis. Wolbachia is a maternally inherited endosymbiont that is commonly found in insects, including a number of mosquito vector species. In Drosophila, Wolbachia mediates antiviral protection against a broad range of RNA viruses. This discovery pointed to a potential strategy to interfere with mosquito transmission of arboviruses by artificially infecting mosquitoes with Wolbachia. This review outlines research on the prevalence of Wolbachia in mosquito vector species and the impact of antiviral effects in both naturally and artificially Wolbachia-infected mosquitoes.

For the rational design of vaccines capable of inducing CD8+ T cell responses knowledge of the identity of the antigen-presenting cell (APC) and the mechanism of antigen presentation is very important. Here, we address these issues for alphavirus-based immunization, in particular immunization with recombinant Semliki Forest virus (rSFV). Studies with dendritic cells (DCs) from various origins revealed that rSFV has a very limited capacity to transfect this cell type in vitro. To further investigate in vivo whether rSFV transfects professional antigen-presenting cells directly or whether the antigens reach APCs via a mechanism of cross-priming we compared the immunological effects of three different SFV-constructs encoding the influenza nucleoprotein (NP). These constructs differ in the amount of NP produced per cell or in the stability of the NP, respectively. Induction of cytotoxic T lymphocytes (CTLs) appeared to benefit from a large amount of stable antigen. In contrast, rapid antigen degradation, and thus availability of antigenic peptides in the transfected cell, was found to be disadvantageous. Based on these in vitro and in vivo results, we hypothesize that antigen presentation after SFV-based immunization proceeds via a mechanism in which APCs are not transfected directly but acquire antigen from other transfected cells and present it to CTLs in a process of cross-priming. (C) 2003 Elsevier Ltd. All rights reserved.