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The COVID-19 pandemic has profoundly affected societies around the world. Although the emergency phase of coronavirus disease 2019 (COVID-19) has ended, the threat it poses remains persistent. This review aims to clarify the mechanisms of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection to support effective management of the disease. A central focus is the host cellular response to the viral infection, with particular emphasis on the role of cytokines. Cytokines play a dual role in antiviral defense: they contribute to the inhibition of viral replication and facilitate the clearance of pathogens, yet dysregulated cytokine responses can result in severe immunopathology. Interferons (type I, type II, and type III) and other cytokines are pivotal in activating intracellular antiviral mechanisms and in orchestrating the recruitment of immune cells through extracellular signaling. Effective immune responses to viral infections are governed not only by primary immune cells—such as dendritic cells, T lymphocytes, and B lymphocytes—but also by the local cytokine milieu shaped by infected and neighboring cells. Given the presence of endogenous inhibitors and autoantibodies in vivo, it is essential to evaluate the functional activity of cytokines in clinical samples. We propose a novel approach to quantify biologically active cytokine levels. Full article

During the Coronavirus Disease 2019 (COVID-19) pandemic, global awareness of infectious diseases increased markedly. Many infectious diseases are transmitted through direct or indirect contact with biological fluids containing pathogens such as viruses and bacteria. This risk is particularly pronounced in environments used by large numbers of unspecified individuals. Public restrooms, therefore, raise significant hygienic concerns, as toilet seats may serve as vectors for indirect transmission. To mitigate this risk, this study proposes a novel toilet seat equipped with an automatic cleaning function. Specifically, after use, the seat surface is automatically wiped by a cleaning cloth, eliminating the need for manual cleaning by staff. A fundamental operational concept is established, emphasizing the determination of an appropriate cleaning initiation timing that allows the cleaning sequence to be completed without compromising user convenience. Based on this concept, a belt–pulley type prototype is developed, and the effectiveness of the proposed cleaning sequence is verified. Subsequently, the prototype is further improved through the introduction of a flexible-rack mechanism. The control methodology, including the design of the electronic circuitry, is described in detail. Using the improved prototype, extensive simulations and experimental evaluations were conducted. The results showed that battery capacity declined at an approximately constant rate of 3% per 10 cycles, with about 70% remaining after 100 cycles. In addition, a single reciprocating cleaning cycle removed over 95% of artificially applied stains across the entire toilet seat. Additional evaluation results are presented in detail. Full article

Background/Objectives: Notwithstanding the declaration by the World Health Organization in May 2023 regarding the conclusion of the COVID-19 pandemic, new cases of this potentially lethal infection continue to be documented globally, exerting a sustained influence on the worldwide economy and social structures. Contemporary SARS-CoV-2 variants, while associated with a reduced propensity for severe acute pathology, retain the capacity to induce long-term post-COVID syndrome, including in ambulatory patient populations. This clinical phenomenon may be attributable to potential autoimmune reactions hypothetically triggered by antiviral antibodies, thereby underscoring the need for developing novel, universal vaccines against COVID-19. The nucleocapsid protein (N), being one of its most conserved and highly immunogenic components of SARS-CoV-2, presents a promising target for such investigative efforts. However, the protective role of anti-N antibodies, generated during natural infection or through immunization with N-based vaccines, alongside the potential adverse effects associated with their production, remains to be fully elucidated. In the present study, we aim to identify potential sites of homology in structures or sequences between the SARS-CoV-2 N protein and human antigens detected using hyperimmune sera against N protein obtained from mice, rabbits, and hamsters. Methods: We employed Western blot analysis of lysates from human cell lines (MCF7, HEK293T, THP-1, CaCo2, Hep2, T98G, A549) coupled with mass spectrometric identification to assess the cross-reactivity of polyclonal and monoclonal antibodies generated against recombinant SARS-CoV-2 N protein with human self-antigens. Results: We showed that anti-N antibodies developed in mice and rabbits exhibit pronounced immunoreactivity towards specific components of the human proteome. In contrast, anti-N immunoglobulins from hamsters showed no non-specific cross-reactivity with either hamster or human proteomic extracts because of the lack of autoreactivity or immunogenicity differences. Subsequent mass spectrometric analysis of the immunoreactive bands identified principal autoantigenic targets, which were predominantly heat shock proteins (including HSP90-beta, HSP70, mitochondrial HSP60, and HSPA8), histones (H2B, H3.1–3), and key metabolic enzymes (G6PD, GP3, PKM, members of the 1st family of aldo-keto reductases). Conclusions: The results obtained herein highlight the differences in the development of anti-N humoral responses in humans and in the Syrian hamster model. These data provide a foundational basis for formulating clinical recommendations to predict possible autoimmune consequences in COVID-19 convalescents and are of critical importance for the rational design of future N protein-based, cross-protective vaccine candidates against novel coronavirus infections. Full article

Importance: The coronavirus disease 2019 (COVID-19) was the third leading cause of mortality in the United States for three years in a row. The genetic contributions to disease severity remain unclear and many previously identified single nucleotide polymorphisms (SNPs) have not been replicated nor linked with functional significance. Objective: To identify SNPs associated with mortality among hospitalized COVID-19 patients supplemented by expression quantitative trait loci (eQTL) evidence to infer plausible functional mechanisms related to COVID-19 severity. Design: A quality-controlled genome-wide association study (GWAS) supported by robust gene-level omnibus kernel association tests (SKAT-O), functional prediction, and eQTL analyses of the top GWAS signal. Setting: Massachusetts General Hospital (MGH). Participants: 370 adult ICU patients with SARS-CoV-2 infection and acute hypoxemic respiratory failure and floor patients with mild hypoxemia managed with supplemental oxygen consecutively admitted to MGH between March and June 2020 (Surge 1), and January and March 2021 (Surge 2) with baseline clinical characteristics and demographics collected. Exposures: Low-pass genotyped SNPs from whole blood and aggregated SNP-sets of potential disease susceptibility loci with $\pm$500 kb flanking regions. Main Outcomes & Measures: Genome-wide individual SNP associations and SNP-set associations with mortality outcomes from 370 severe COVID-19 cases. Results: After LD pruning (<0.8) and false discovery rate adjustment (<0.05), we identified rs7420371 G>A of the receptor transporter protein 5 (RTP5) gene as the top independent signal significantly associated with 30- and 60-day mortality among severe COVID-19 patients (OR, 2.32; 95% CI, 1.59–3.39; p = 4.92 × 10⁻⁹ and OR, 2.06; 95% CI, 1.43–2.97; p = 5.43 × 10⁻⁸, respectively). SKAT-O analyses on the RTP5 SNP-set showed associations with both mortality outcomes (p = 5.90 × 10⁻⁵ and 6.17 × 10⁻⁵, respectively). eQTL analysis showed rs7420371 A allele significantly upregulated the mRNA expression of RTP5 in 266 cerebellum tissues, in 277 cerebellar hemisphere tissues, and in 270 cerebral cortex samples. Conclusions & Relevance: We discovered a novel, independent, and potentially functional SNP RTP5 rs7420371 G>A to be significantly associated with COVID-19 mortality. The A allele is significantly associated with elevated mRNA expression of RTP5 in the brain, an important protein coding gene that modulates olfactory binding and taste perceptions in response to SARS-CoV-2 infection. Full article

Background: Adjuvants enhance the immune response to antigens incorporated in vaccine formulations. Given that the majority of infectious agents enter the body through mucosal surfaces, efficacious vaccines must generate protective immunity at these sites, which serve as the first line of defense. There is a need for mucosal adjuvants; hence, we explored the potential of repurposing existing drugs with established safety profiles in humans. Polymyxins are a class of clinically used antibiotics. They are cationic peptides and mast cell activators, which are a novel class of vaccination adjuvants. The goal was to assess the adjuvant properties of Polymyxin B microparticles in combination with vaccine candidates previously developed in our laboratory, such as microparticulate gonorrhea, influenza, measles, Zika, and canine coronavirus vaccines, and to compare their performance with FDA-licensed adjuvants, such as MF59 and Alum. Methods: Polymyxin microparticles were formulated using a double emulsion method, and the toxicity profile and autophagosome generation of Polymyxin B microparticles were assessed. The immunogenic potential of Polymyxin B in these vaccines was studied using multiple parameters such as nitric oxide release using Griess assay and immune profiling using flow cytometry for markers such as MHC I, MHC II, CD40, and CD80. Results: Polymyxin B microparticles were found to be non-cytotoxic to dendritic cells up to 500 μg/mL. Polymyxin B promoted autophagosome formation and nitric oxide release, and showed the upregulation of MHC I, MHC II, CD80, and CD40 pathways. Conclusions: The adjuvant activity of Polymyxin B across various vaccine platforms is significantly comparable to FDA-approved adjuvants, which is a critical requirement for generating T cell responses such as helper T cell and cytotoxic CD8+ T cell responses. Full article

Background: The minimized pan-coronavirus (CoV) vaccine-1 developed by our laboratory contained pDNA sequences of feline coronavirus serotype-1 (FCoV1) and SARS-CoV2 (SCoV2) spike B-cell epitopes plus FCoV/SCoV2-conserved, CoV-specific polymerase cytotoxic T-lymphocyte (CTL) epitopes formulated in lipid nanoparticle (LNP). Only FCoV2 infects feline cell lines needed for developing native challenge inoculum that causes feline infectious peritonitis (FIP). Hence, Pilot Study 1 evaluated the therapeutic efficacy and safety of the pan-CoV vaccine-1 in feline immunodeficiency virus (FIV)-infected cats, with or without FCoV1 coinfection. Pilot Study 2 evaluated the cross-protective effect of pan-CoV vaccines in specific-pathogen-free (SPF) cats against intranasal challenge with FIP virus serotype 2 (FIPV2). Methods: In Study 1, we vaccinated two FIV-infected cats (one negative and another positive for FCoV1 coinfection) intramuscularly twice with CTL epitopes-LNP vaccine and later twice with pan-CoV vaccine-1. Controls included two unvaccinated FIV-infected cats with or without FCoV1 coinfection. Study 2 assessed the sequential vaccinations of three pan-CoV vaccines in four SPF cats. The first two vaccinations were with pan-CoV vaccine-2, followed by pan-CoV vaccine-3 (twice), and lastly with pan-CoV vaccine-1 (once). Three SPF controls included two cats immunized with LNP and one lacking any immunization. Pan-CoV vaccine-2 contained pDNAs with modified FCoV1/SCoV2 B-cell epitopes plus CTL epitopes in LNP. Pan-CoV vaccine-3 contained only pDNAs with FCoV1 B-cell epitopes plus CTL epitopes in LNP. Results: Study 1 demonstrated no adverse effect with 25 μg and 50 μg CTL epitopes-LNP vaccine and 50 μg pan-CoV vaccine-1. However, 100 μg pan-CoV vaccine-1 caused fever 24 h later, which was resolved by a single Meloxicam treatment. Both vaccinees developed cross-FCoV2 neutralizing antibodies (XNAbs), immunoblot binding antibodies (bAbs) to FCoV1 receptor-binding domain (RBD), and T-cell responses to FCoV1 RBD, whereas one vaccinee also developed bAbs to SCoV2 RBD. Study 2 demonstrated no adverse effects after each vaccination. Three vaccinees developed low-titer XNAbs and bAbs to FCoV2 spike-2 by the fourth vaccination. Upon challenge, all cats developed FCoV2 NAbs and bAbs to FCoV2 nucleocapsid and RBD. High vaccine-induced T-cell responses to FCoV1 RBD and T-cell mitogen responses declined with an increase in responses to FCoV2 RBD at three weeks post-challenge. Two of the three controls died from FIP, whereas one vaccinee, with the lowest vaccine-induced immunity, died from skin vasculitis lesions and detection of FIPV2 infection by semi-nested RT-snPCR in feces. Conclusions: In Pilot Study 1, the pan-CoV vaccine-LNP dose of 50 μg had no adverse effects, but adverse effects were observed at 100 μg dose. In Pilot Study 2, the FCoV1-based B-cell vaccine(s) induced low levels of XNAbs against FIPV2 and delayed challenge infection against high-dose FIPV2. The high-dose FIPV2 infections in the vaccinated and control cats started to clear, by single housing at 23–26 weeks post-challenge, whereas two cats in Pilot Study 1 cleared natural FCoV1 transmission by 26 weeks post-infection. Full article

The utilisation of cardiopulmonary bypass (CPB) during cardiac surgery is often associated with complex haemostatic perturbations, frequently manifesting as a paradoxical risk of both bleeding and thrombosis. This is postulated to be driven by systemic inflammation, endothelial activation and contact activation of the coagulation cascade due to extracorporeal circulation. However, the coronavirus disease 2019 (COVID-19) pandemic revealed a unique hypercoagulable state, termed COVID-19-associated coagulopathy (CAC), also observed in those vaccinated against COVID-19. CAC displays similar physiological manifestations to those of disseminated intravascular coagulation (DIC), characterised by elevated fibrinogen and D-dimer values. The precise pathogenesis of CAC requires further elucidation though proposed mechanisms include: an exaggerated inflammatory response to COVID-19 infection or antibody proliferation due to vaccination, direct epithelial cell damage mediated by angiotensin converting enzyme 2, and ‘hypoxithrombosis’. CAC has since provided a unique framework to understand and potentially mitigate coagulation complications encountered during CPB in the post-pandemic era, as it is no longer sufficient to view COVID-19 as a transient influence on surgical risk. Rather, it must be recognized as a persistent modifier of the haemostatic environment across the population, with direct implications upon patient selection, intraoperative management and postoperative care in cardiac surgery. This review examines the pathological drivers behind CAC alongside the insights obtained from CAC management during ECMO deployment, to investigate the potential translation of such knowledge into improved anticoagulation strategies and monitoring during cardiac surgery. The use of alternative anticoagulants including factor XI inhibitors and the modulation of heparinase activity offers promising avenues to attenuate coagulopathies more commonly observed during CPB in the post-pandemic climate, whilst anti-Xa assays and viscoelastic testing have offered applicability to modern perfusion practices. By bridging the knowledge gained during the pandemic with that of conventional CPB, this review aims to inform future strategies for haemostasis management in cardiac surgery in a novel cohort of surgical patients. Full article

Implementation of novel antiviral coatings and textiles, which can be utilised in the production of personal protective equipment, has the potential to enhance public health security against future pandemic outbreaks. Respiratory viruses, particularly SARS-CoV-2, responsible for COVID-19, have emerged as a major global concern due to their rapid transmission and high mortality rates, leading to nearly seven million deaths worldwide between 2020 and 2025. This statistic underscores the necessity for the development and implementation of advanced antiviral materials to prevent viral infections. This research focused on the in vitro evaluation of the antiviral properties of three antibacterial compounds containing silver (Ag) that were functionalized with coatings. We assessed onsite synthesised Ag powder in comparison to commercially available antibacterial additives, which included nanosilver on colloidal silica (AgSiO₂) and silver sodium hydrogen zirconium phosphate (AgNaOPZr), as potential antiviral agents in coatings against human coronavirus (HCoV). Antiviral assessments revealed that coatings containing Ag at higher concentrations (2.5 and 5%) exhibited limited antiviral effectiveness, with a titer reduction in log < 2. In contrast, the functionalization of AgSiO₂ on coatings significantly suppressed viral replication resulting in a notable reduction in virus titer of log ≥ 2 for all tested concentrations. Full article

Background: Little is known about women’s contraceptive use in the United States during the novel coronavirus (“COVID-19”) pandemic and the risk of unintended pregnancy. Methods: We compared the weighted response rates on contraception use for female respondents aged 18–44 from the Behavioral Risk Factor Surveillance System (BRFSS) between 2019 and 2022. Results: Our study reveals a significant increase of 16.1% (CI = 0.145, 0.177) in the proportion of women using contraception in 2022 as compared to 2019. The largest increase in the use of non-reversible contraception was seen in the proportion of female sterilization, at 3.0% (CI = 0.017, 0.043), mostly attributed to non-Hispanic Black individuals with a 12% increase (CI = 0.046, 0.198). The largest decrease was seen in the use of condoms, at 7.4% (CI = −0.094, −0.055). This was driven by both non-Hispanic Black and multiracial groups, each experiencing a 19% decrease (CI = −0.251, −0.127; CI = −0.304, −0.068, respectively). The proportion of women at risk of unintended pregnancy increased by 3.7% (CI = 0.010, 0.063). These increases were observed among those with an income of less than USD 15k, showing a 14.9% increase (CI = 0.037, 0.262). Older females and those with Medicaid insurance were more likely to use female sterilization. Hispanics, college graduates, and those with Medicaid insurance were more likely to use condoms. Non-White females and those without annual checkups were more at risk of unintended pregnancy. Conclusions: Contraceptive methods shifted among females with slightly increased sterilization in the years 2019 to 2022. Full article

Merbecovirus, a subgenus of coronaviruses that includes the highly pathogenic Middle East respiratory syndrome coronavirus (MERSr-CoV), poses a significant zoonotic threat. To better understand its host adaptation and potential for cross-species transmission, we conducted a comprehensive analysis of codon usage patterns in 1967 Merbecovirus sequences. Phylogenetic analysis confirmed the division of Merbecoviruses into seven distinct clusters. Codon usage bias was found to be low and predominantly shaped by natural selection, with a consistent A/U-rich composition across the genome. Codon adaptation index (CAI) and relative codon deoptimization index (RCDI) analyses indicate that Merbecovirus exhibits potential host adaptation to Sus scrofa (pigs), Equus caballus (horses), and Oryctolagus cuniculus (rabbits), suggesting a risk of cross-species transmission. Strikingly, this genomic-level adaptation prediction is supported by emerging functional evidence: recent studies have demonstrated that key Merbecovirus lineages utilize diverse cell entry receptors (DPP4 or ACE2), a fundamental determinant of host tropism. For instance, the ability of the HKU5 lineage to utilize ACE2 receptors from mustelids like minks (Neogale vison) provides mechanistic support for the host adaptability trends inferred from our genomic analyses. By integrating existing receptor specificity data, this study provides the first systematic, large-scale analysis of codon usage across the Merbecovirus subgenus, elucidating key mechanisms of genomic adaptation and viral evolution. Our analytical framework provides a novel comparative perspective on host diversity and pinpoints specific surveillance priorities for mitigating future spillover risks. Full article

Viral zoonoses or viral pathogens transmitted from animals to humans—constitute a rapidly intensifying global health and economic challenge. They are responsible for an estimated 2.5 billion illnesses and 2.7 million deaths annually, representing nearly 60% of all infectious diseases and 75% of newly emerging infections. Recent outbreaks, including Coronavirus disease 2019 (COVID-19), Ebola, Nipah, and avian influenza, underscore their capacity to overwhelm health systems, with COVID-19 alone projected to reduce global Gross Domestic Product by USD 22 trillion by 2025 and impose annual healthcare costs of USD 2–3 trillion. Beyond mortality and morbidity, zoonotic events disrupt trade, depress rural livelihoods, and inflict agricultural losses exceeding USD 100 billion per outbreak, with impacts disproportionately borne by low- and middle-income countries. Hotspot regions across tropical North and South America, Asia, and Central Africa remain especially vulnerable due to accelerating land use change, climate variability, and intensified wildlife–human interfaces. While the Global One Health Index highlights high regional heterogeneity, with sub-Saharan Africa scoring lowest, a critical gap persists between the conceptual strength of One Health and its operationalization in resource-limited settings. This review synthesizes evidence on drivers, clinical manifestations, and socioeconomic burdens of viral zoonoses, while highlighting novel perspectives on equity gaps, co-infection dynamics, and limitations of global preparedness initiatives. We argue that current strategies remain over-reliant on donor-driven agendas and insufficiently integrated across sectors. Addressing future zoonotic threats requires prioritizing surveillance in high-risk geographies, integrating epidemiological and economic data for preparedness planning, and supporting context sensitive One Health approaches that confront political, financial, and structural barriers to implementation. Full article

In order to effectively control the spread of the 2019 novel coronavirus (COVID-19), China has undertaken relatively strict blockade measures, which can effectively reduce population mobility and eliminate transmission pathways at the source. Therefore, it is of great significance to understand the impact of urban blockades on the air quality before, during, and after COVID-19. This study uses data collected from monitoring stations in Xi’an, a typical city in northwestern China, from 2018 to 2023 to conduct an in-depth analysis of the changes in concentration of various pollutants in the atmosphere from a spatiotemporal perspective. The results showed that the average concentrations of particulate matter with aerodynamic diameters less than 2.5 µm (PM_2.5), particulate matter with aerodynamic diameters less than 10 µm (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), and carbon monoxide (CO) decreased during the epidemic lockdown (2020–2022) by 18.7%, 15.4%, 29.4%, 20.9%, 0.03%, and 28.1%, respectively. After the implementation of urban lockdown (2023), the annual average concentrations of the five major pollutants other than O₃ decreased, while the concentration of O₃ increased. The monthly changes in concentration of PM_2.5, PM₁₀, CO, SO₂, and NO₂ were similar during 2018–2023, being “higher in winter and lower in summer”. The monthly average concentration of O₃ changed in a “unimodal” manner. The concentrations of SO₂, NO₂, and PM₁₀ decreased the most in January, by 46.4%, 33.5%, and 26.4%, respectively. The concentration of CO decreased the most in April, by 37.3%. PM_2.5 decreased the most in May, with a decrease of 26.7%. O₃ showed the largest increase in November, by 28.6%. After taking relevant measures, the concentrations of various pollutants and their correlations decreased. However, after resuming work, the concentrations of pollutants were still relatively high, and long-term management of air quality in Xi’an is still needed. These results provide a scientific basis for formulating more precise and effective air pollution control strategies. Full article

Background/Objectives: Since its emergence, COVID-19—caused by the novel coronavirus SARS-CoV-2—has affected millions globally and led to over 1.2 million deaths in the United States alone. This global impact, coupled with the emergence of five new human coronaviruses over the past two decades, underscores the urgency of understanding its pathogenic mechanisms at the molecular level—not only for managing the current pandemic but also preparing for future outbreaks. Small non-coding RNAs (sncRNAs) critically regulate host and viral gene expression, including antiviral responses. Among the molecular regulators implicated in antiviral defense, the microRNA-processing enzyme Drosha has emerged as a particularly intriguing factor. In addition to its canonical role, Drosha also exerts a non-canonical, interferon-independent antiviral function against several RNA viruses. Methods: To investigate this, we employed q/RT-PCR, Western blot, and immunocytochemistry/immunofluorescence in an immortalized normal human lung/bronchial epithelial cell line (NuLi-1), as well as a human colorectal carcinoma Drosha CRISPR knockout cell line. Results: In this study, we observed a striking shift in Drosha isoform expression following infection with multiple SARS-CoV-2 variants. This shift was absent following treatment with the viral mimetic poly (I:C) or infection with other RNA viruses, including the non-severe coronaviruses HCoV-OC43 and HCoV-229E. We also identified a distinct alteration in Drosha’s cellular localization post SARS-CoV-2 infection. Moreover, Drosha ablation led to reduced expression of SARS-CoV-2 genomic and sub-genomic targets. Conclusions: Together, these observations not only elucidate a novel aspect of Drosha’s antiviral role but also advance our understanding of SARS-CoV-2 host–pathogen interactions, highlighting potential therapeutic avenues for future human coronavirus infections. Full article

Background/Objectives: Although the U.S. Food and Drug Administration (FDA) has approved one antiviral treatment and authorized others for emergency use, there is no fully effective antiviral therapy for coronavirus disease 2019 (COVID-19), which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Assays detecting virus-specific immunoglobulins (Ig) or nucleic acids in large-scale epidemiological, vaccine, and drug development studies remain limited due to high costs, reagent accessibility, and cumbersome protocols. Methods: A multiplex bead-based assay was developed to simultaneously detect human IgM, IgG, and IgA antibodies against the SARS-CoV-2 spike receptor binding domain (RBD) in serum using flow cytometry. Assay performance was evaluated for sensitivity, specificity, reproducibility, and cross-reactivity and compared to another immunoassay platform. Results: The assay enabled simultaneous measurement of three antibody isotypes across 624 samples within 2 h. Intra-plate coefficients of variation (CVs) ranged from 3.16 to 6.71%, and inter-plate CVs ranged from 3.33 to 5.49%, demonstrating high reproducibility. The platform also quantified background noise from nonspecific binding, facilitating straightforward data interpretation. Conclusions: This novel, flexible multiplex bead-based assay utilizing a well-established platform provides a rapid and reproducible approach for detecting SARS-CoV-2-specific antibodies. Its high throughput capacity and low variability make it well suited for large-scale epidemiological, vaccine, and therapeutic studies. The platform’s adaptability further supports application to other infectious diseases, offering an ideal tool for broad immunological surveillance. Full article

Background. To date, a number of human pathogenic viruses are still unaddressed by the current repertoire of approved antiviral drugs. In order to widen this spectrum of preventive measures against virus infections, we have focused on additional host targets that exert interesting virus-supportive functions. Inhibitors of cyclin-dependent kinase 8 (CDK8) have been found to exhibit highly pronounced and relatively broad antiviral activity. Objectives. The current research question concerning the potential for broad-spectrum antiviral drug activity should be addressed in detail to understand the mechanistic basis of the antiviral target function of CDK8. Materials and Methods. We established and specifically customized six assay systems, three of these newly developed for the present study, to corroborate the range of CDK8 inhibitors’ antiviral activity against four α-, β-, and γ-herpesviruses as well as two non-herpesviruses. Results. Similar to our earlier analysis of CDK7 and CDK9 inhibitors, the clinically relevant CDK8 inhibitors currently in use demonstrated antiherpesviral activity in cell-culture-based infection models. Interestingly, the antiviral efficacy against various human and animal cytomegaloviruses was particularly strong at nanomolar concentrations, whereas other herpesviruses or non-herpesviruses showed an intermediate or low sensitivity to CDK8 inhibitors. Thus, this approach provided novel insights into the inhibitory potential of the CDK8 inhibitors, such as CCT-251921, MSC-2530818, and BI-1347, when analyzed against equine herpesvirus 1 (EHV-1, α-herpesvirus), human herpesvirus 6A (HHV-6A, β), Epstein–Barr virus (EBV, γ), murine herpesvirus 68 (MHV-68, γ), vaccinia virus (VV, non-herpes DNA virus), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, non-herpes RNA virus). Conclusions. Our results confirm that drug sensitivity to CDK8 inhibitors, on the one hand, is very strong for certain viruses and, on the other hand, varies widely within the spectrum of viruses and host cell types analyzed. This suggests that CDK8 may play several different roles in viral replication. The option of a refined CDK8-specific antiviral drug targeting is discussed. Full article