Virus In Cell Culture Research Articles

STRAIN SELECTION AND CULTIVATION OF FOOT-AND-MOUTH DISEASE VIRUSES FOR THE DEVELOPMENT OF A TRIVALENT INACTIVATED VACCINE

Foot-and-mouth disease is a well-known transboundary animal disease and has been recognised as a priority disease by the Steering Committee of the Global Framework for the Progressive Control of Transboundary Animal Diseases in Europe. The territory of the Republic of Kazakhstan is generally free of foot-and-mouth disease, however, sporadic cases of foot-and-mouth disease occur in various regions of the country as a result of importation from unfavorable countries. Epizootic safety in the Republic of Kazakhstan is maintained by vaccinating animals in the border areas of the southern and eastern regions. Inactivated vaccines against serotypes A, O, Asia produced by the All-Russian Research Institute of Animal Health (Russia) are used for vaccination. Continuous seromonitoring is carried out to maintain the level of post-vaccination antibodies at a high level, ensuring the immunity of animals to foot-and-mouth disease. However, despite all the measures taken, sporadic outbreaks of foot-and-mouth disease cause damage to livestock farming in the Republic of Kazakhstan. The effectiveness of preventive measures using vaccination depends on the strain used in the vaccine. The closer the strain used in the vaccine is genetically to the viruses circulating in that area, the more effective the preventive measures will be and the research conducted to create the most immunogenic domestic anti-foot-and-mouth disease vaccines have scientific and practical significance. This article presents the results of the selection of foot-and-mouth disease virus strains previously circulating in the territory of the Republic of Kazakhstan and studies their cultural and biological properties. Studies of the above-mentioned strains on adaptation to a transplantable cell culture line were conducted, the stability of cultural properties was studied over 10 generations and the stability was confirmed by the PCR method. Also, based on the studies, it was found that the maximum accumulation of the virus in cell culture occurs at a multiplicity of infection of 0.01-0.1 TCID50/cell. The reproductive activity of the studied isolates was within 6.5-7.25 lg TCID50/cm3 when cultivated for 16 hours.

Antiviral Activity of Plant-Based Additives Against African Swine Fever Virus (ASFV) in Feed Ingredients.

African swine fever (ASF) is one of the deadliest swine diseases with haemorrhagic symptoms and a high mortality rate. Plant-derived additives are potential antiviral agents against viruses due to their environmental and user-friendly properties. This study aims to evaluate the efficacy of plant-based additives (Phyto.A04 and Phyto.B) compared to an organic acid blend (OAB) in inactivating ASF virus (ASFV) in cell culture and feed. ASFV-spiked feed was treated with individual or combined additives such as OAB, Phyto.A04 and Phyto.B. The viability of ASFV after treatment of ASFV-spiked feed with additives was then confirmed by both methods, real-time PCR and cell culture. The results of the in vitro test with cell cultures showed that all three additives (OAB, Phyto.A04 and Phyto.B) exerted a strong virucidal effect on ASFV in porcine alveolar macrophage cells. OAB at a concentration of 0.3% reduced the virus concentration from 4.48 log10 HAD50/mL after 1 day of treatment (day 1) to 3.29 log10 HAD50/mL after 3 days of treatment (day 3) and remained undetected after 7 days of treatment (day 7). In Phyto.A04 with 1%, the virus was only detectable on day 1 (3.53 log10 HAD50/mL). Phyto.B with 0.01% and 0.05% both showed good efficacy in completely inhibiting virus presence on days 3 and 7. All additives, OAB, Phyto.A04 and Phyto.B, were able to inactivate ASFV in a dose-dependent manner, as confirmed by cell culture and PCR methods. The combination of additives at different concentrations consistently improved the virucidal results.

Elasticity of the HIV-1 core facilitates nuclear entry and infection.

HIV-1 infection requires passage of the viral core through the nuclear pore of the cell, a process that depends on functions of the viral capsid. Recent studies have shown that HIV-1 cores enter the nucleus prior to capsid disassembly. Interactions of the viral capsid with the nuclear pore complex are necessary but not sufficient for nuclear entry, and the mechanism by which the viral core traverses the comparably sized nuclear pore is unknown. Here we show that the HIV-1 core is highly elastic and that this property is linked to nuclear entry and infectivity. Using atomic force microscopy-based approaches, we found that purified wild type cores rapidly returned to their normal conical morphology following a severe compression. Results from independently performed molecular dynamic simulations of the mature HIV-1 capsid also revealed its elastic property. Analysis of four HIV-1 capsid mutants that exhibit impaired nuclear entry revealed that the mutant viral cores are brittle. Adaptation of two of the mutant viruses in cell culture resulted in additional substitutions that restored elasticity and rescued infectivity and nuclear entry. We also show that capsid-targeting compound PF74 and the antiviral drug Lenacapavir reduce core elasticity and block HIV-1 nuclear entry at concentrations that preserve interactions between the viral core and the nuclear envelope. Our results indicate that elasticity is a fundamental property of the HIV-1 core that enables nuclear entry, thereby facilitating infection. These results provide new insights into the role of the capsid in HIV-1 nuclear entry and the antiviral mechanisms of HIV-1 capsid inhibitors.

Novel Abietane type Sugar Triazole Hybrids and Amides against SARS‐CoV‐2 Spike Glycoprotein and Influenza A Virus

Abietane type diterpenic (dehydroabietic, 2,3‐dihydroquinopimaric and maleopimaric) acids were converted by the acid chloride method into a series of aliphatic and heterocyclic amine spacered conjugates. A number of structurally novel derivatives holding 1,2,3‐triazole moieties were designed and synthesized by treating of the propargylated amides and esters with a sugar azides using the Cu(I)‐catalyzed click chemistry approach. The synthesized N‐containing diterpene derivatives were tested for their potential inhibition of influenza A/PuertoRico/8/34 (H1N1) virus in MDCK cell culture and SARS‐CoV‐2 pseudovirus in BHK‐21‐hACE2 cells. Among tested forty‐five compounds ten derivatives were the most efficacious against influenza virus A with IC50 0.7‐63.4 μM together with high selectivity index SI value from 11 from 94. Dihydroquinopimaric acid N‐ethylpiperazine‐amide and dehydroabietic acid 1,2,3‐triazoles spacered with glucose and lactose showed anti‐SARS‐CoV‐2 pseudovirus activity with EC50 values of 1.79‐25.46 µM. Molecular docking and dynamics modeling investigated the binding mode of the lead compounds into the binding pocket of influenza A virus M2 protein and the RBD domain of SARS‐CoV‐2 spike glycoprotein.

A Comparative Evaluation of Three Diagnostic Assays for the Detection of Human Monkeypox.

Accurate and early diagnosis of monkeypox virus (MPXV) is crucial for controlling epidemics and treating affected individuals promptly. This study aimed to assess the analytical and clinical performance of the MolecisionTM Monkeypox Virus qPCR Assay, Biorain Monkeypox Virus ddPCR Assay, and MAGLUMI® Monkeypox Virus Ag (chemiluminescence immunoassay, CLIA) Assay. Additionally, it aimed to compare the clinical application of antigen and nucleic acid assays to offer insights into using commercial monkeypox assay kits. Specimens from 117 clinical patients, serial diluted virus cell culture supernatant, and artificially created positive samples were tested to evaluate the performance of these assay kits for MPXV diagnostics. The Biorain Monkeypox Virus ddPCR Assay had a limit of detection (LoD) of 3.89 CCID50/mL, while the MolecisionTM Monkeypox Virus qPCR Assay had an LoD of 15.55 CCID50/mL. The MAGLUMI® Monkeypox Virus Ag (CLIA) Assay had an LoD of 0.500 pg/mL. The accuracy of the MolecisionTM Monkeypox Virus qPCR Assay was comparable to the Biorain Monkeypox Virus ddPCR Assay, and the MAGLUMI® Monkeypox Virus Ag (CLIA) Assay demonstrated high sensitivity. The specificity of all three MPXV diagnostic assays for clinical specimens with potential cross-reacting substances was 100%. In conclusion, this study provides valuable insights into the clinical application of monkeypox assays, supporting efforts to mitigate and control the spread of monkeypox.

Synergistic activity of an RNA polymerase PA-PB1 interaction inhibitor with oseltamivir against human and avian influenza viruses in cell culture and in ovo

In search of novel therapeutic options to treat influenza virus (IV) infections, we previously identified a series of inhibitors that act by disrupting the interactions between the PA and PB1 subunits of the viral RNA polymerase. These compounds showed broad-spectrum antiviral activity against human influenza A and B viruses and a high barrier to the induction of drug resistance in vitro. In this short communication, we investigated the effects of combinations of the PA-PB1 interaction inhibitor 54 with oseltamivir carboxylate (OSC), zanamivir (ZA), favipiravir (FPV), and baloxavir marboxil (BXM) on the inhibition of influenza A and B virus replication in vitro. We observed a synergistic effect of the 54/OSC and 54/ZA combinations and an antagonistic effect when 54 was combined with either FPV or BXM. Moreover, we demonstrated the efficacy of 54 against highly pathogenic avian influenza viruses (HPAIVs) both in cell culture and in the embryonated chicken eggs model. Finally, we observed that 54 enhances OSC protective effect against HPAIV replication in the embryonated eggs model. Our findings represent an advance in the development of alternative therapeutic strategies against both human and avian IV infections.

Innovative fixed bed bioreactor platform: Enabling linearly scalable adherent cell biomanufacturing with real-time biomass prediction from nutrient consumption.

Scalable single-use adherent cell-based biomanufacturing platforms are essential for unlocking the full potential of cell and gene therapies. The primary objective of this study is to design and develop a novel fixed bed bioreactor platform tailored specifically for scaling up adherent cell culture. The bioreactor comprises a packed bed of vertically stacked woven polyethylene terephthalate mesh discs, sandwiched between two-fluid guide plates. Leveraging computational fluid dynamics modeling, we optimized bioreactor design to achieve uniform flow with minimal shear stress. Residence time distribution measurements demonstrated excellent flow uniformity with plug flow characteristics. Periodic media sampling coupled with offline analysis revealed minimal gradients of crucial metabolites (glucose, glutamine, lactate, and ammonia) across the bioreactor during cell growth. Furthermore, the bioreactor platform demonstrated high performance in automated cell harvesting, with ≈96% efficiency and ≈98% viability. It also exhibited linear scalability in both operational parameters and performance for cell culture and adeno-associated virus vector production. We developed mathematical models based on oxygen uptake rates to accurately predict cell growth curves and estimate biomass in real-time. This study demonstrates the effectiveness of the developed fixed-bed bioreactor platform in enabling scalable adherent cell-based biomanufacturing with high productivity and process control.

Virological characteristics of the SARS-CoV-2 Omicron EG.5.1 variant.

In middle to late 2023, a sublineage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron XBB, EG.5.1 (a progeny of XBB.1.9.2), is spreading rapidly around the world. We performed multiscale investigations, including phylogenetic analysis, epidemic dynamics modeling, infection experiments using pseudoviruses, clinical isolates, and recombinant viruses in cell cultures and experimental animals, and the use of human sera and antiviral compounds, to reveal the virological features of the newly emerging EG.5.1 variant. Our phylogenetic analysis and epidemic dynamics modeling suggested that two hallmark substitutions of EG.5.1, S:F456L and ORF9b:I5T are critical to its increased viral fitness. Experimental investigations on the growth kinetics, sensitivity to clinically available antivirals, fusogenicity, and pathogenicity of EG.5.1 suggested that the virological features of EG.5.1 are comparable to those of XBB.1.5. However, cryo-electron microscopy revealed structural differences between the spike proteins of EG.5.1 and XBB.1.5. We further assessed the impact of ORF9b:I5T on viral features, but it was almost negligible in our experimental setup. Our multiscale investigations provide knowledge for understanding the evolutionary traits of newly emerging pathogenic viruses, including EG.5.1, in the human population.

Kinetics of SARS-CoV-2 infection biomarkers in a household transmission study

SARS-CoV-2 is the causative agent of COVID-19. Timely and accurate diagnostic testing is vital to contain the spread of infection, reduce delays in treatment and care, and inform patient management. Optimal specimen type (e.g. nasal swabs or saliva), timing of sampling, viral marker assayed (RNA or antigen), and correlation with viral infectivity and COVID-19 symptoms severity remain incompletely defined. We conducted a field study to evaluate SARS-CoV-2 viral marker kinetics starting from very early times after infection. We measured RNA and antigen levels in nasal swabs and saliva, virus outgrowth in cell culture from nasal swabs, and antibody levels in blood in a cohort of 30 households. Nine household contacts (HHC) became infected with SARS-CoV-2 during the study. Viral RNA was detected in saliva specimens approximately 1–2 days before nasal swabs in six HHC. Detection of RNA was more sensitive than of antigen, but antigen detection was better correlated with culture positivity, a proxy for contagiousness. Anti-nucleocapsid antibodies peaked one to three weeks post-infection. Viral RNA and antigen levels were higher in specimens yielding replication competent virus in cell culture. This study provides important data that can inform how to optimally interpret SARS-CoV-2 diagnostic test results.

Hepatitis B Virus Neutralization with DNA Origami Nanoshells.

We demonstrate the use of DNA origami to create virus-trapping nanoshells that efficiently neutralize hepatitis B virus (HBV) in cell culture. By modification of the shells with a synthetic monoclonal antibody that binds to the HBV envelope, the effective neutralization potency per antibody is increased by approximately 100 times compared to using free antibodies. The improvements in neutralizing the virus are attributed to two factors: first, the shells act as a physical barrier that blocks the virus from interacting with host cells; second, the multivalent binding of the antibodies inside the shells lead to stronger attachment to the trapped virus, a phenomenon known as avidity. Pre-incubation of shells with HBV and simultaneous addition of both components separately to cells lead to comparable levels of neutralization, indicating rapid trapping of the virions by the shells. Our study highlights the potential of the DNA shell system to rationally create antivirals using components that, when used individually, show little to no antiviral effectiveness.

A potential candidate for Zika virus vaccine

Abstract Zika virus (ZIKV) caused a large outbreak in Brazil during 2015-2016 and sporadic cases globally. In light of the potential for the virus to reemerge, developing a potent Zika vaccine is crucial. In this study, we aimed to enhance the immunogenicity of ZIKV by isolating a single clone from clinical human isolates. Initial vaccination of Balb/c mice with inactivated clinical ZIKV (ZIKV-P0) failed to generate neutralizing antibodies. We turned to adapt the Virus in cell culture by serial passages in Vero cells and isolated a single clone by plaque purification. ZIKV-1_PP4, one of the purified clones, exhibited high titer and homogeneous morphology. Prime-boost immunization with inactivated ZIKV-1_PP4 antigen induced significant neutralizing antibody responses in Balb/c mice. Notably, when challenged with ZIKV, mice immunized with ZIKV-1_PP4 showed reduced susceptibility compared to those immunized with ZIKV-1_P0. Additionally, ZIKV-1_PP4 infection showed enhanced recruitment of innate immune cells, including neutrophils, monocytes, and DCs. Furthermore, DCs from ZIKV-1_PP4 infected mice expressed higher levels of costimulatory molecules, with elevated levels of IL-12, IFN-γ, IL-1β, and TNF-α. In summary, our study demonstrated that plaque-purified ZIKV-1_PP4 significantly triggered heightened activation of innate immune responses and improved the generation of neutralizing antibodies. These findings underscore the effectiveness of this vaccine candidate against ZIKV.

Assessment of the Impact of Polycyclic Derivatives of the Frame Series on the Replicative Properties of the SARS-CoV-2 Virus in an <I>in vitro</I> Experiment

The aim of the work was to determine the cytotoxicity and the influence of polycyclic derivatives of the framework series on the replicative properties of the SARS-CoV-2 virus in Vero-E6 cell culture in vitro. Materials and methods. The virus inhibiting effect of 50 adamantane and bicyclo[3.3.1]nonane derivatives with carbocyclic and heterocyclic substituents was investigated. The studies were carried out on Vero-E6 cell culture by assessing the cytopathic effect of the virus. The impact of the compounds on the replicative properties of the SARS-CoV-2 virus was estimated by the decrease in virus titer in the presence of the compounds compared to the control. Based on the virus titer values in the presence of a series of successively decreasing concentrations of the compound, the 50 % effective concentration was calculated.Results and discussion. A study of polycyclic derivatives of the framework series has identified two compounds with antiviral properties against the SARS-CoV-2 virus. Among bicyclo[3.3.1]nonane derivatives containing heterocyclic fragments, compound No. 15144 has showed an inhibitory effect against the SARS-CoV-2 virus. The protective effect of the compound was manifested in maximum tolerable concentration (MTC) (70.0 μg/ml) and ½ MTC (35.0 µg/ml). A decrease in virus titers under the influence of MTC by 0.95 lg TCD50/ml, in ½ MTC (35.0 μg/ml) – by 0.35 lg TCID50/ml has been detected. The effective concentration (EC50) value of the compound No. 15144 was 64.0 μg/ml, the MTC/EC50 ratio was 1.09. Compound No. 14838 (adamantane derivative containing carbocyclic fragments) had less pronounced antiviral activity. As a result of research, it has been established that sample No. 14838 at a dose of MTC (45.0 μg/ml) reduces the infectious titer by 0.78 lg TCD50/ml, in ½ MTC (22.5 μg/ml) by 0.15 lg TCD50/ml compared to the control. The EC50 value of compound No. 14838 was 37.0 μg/ml, the MTC/EC50 ratio was 1.22.

Dynamics of viral DNA shedding and culture viral DNA positivity in different clinical samples collected during the 2022 mpox outbreak in Lombardy, Italy

BackgroundMpox virus (MPXV) has recently spread outside of sub-Saharan Africa. This large multicentre study was conducted in Lombardy, the most densely populated Italian region accounting for more than 40% of Italian cases. The present study aims to: i) evaluate the presence and the shedding duration of MPXV DNA in different body compartments correlating the MPXV viability with the time to onset of symptoms; ii) provide evidence of MPXV persistence in different body compartment as a source of infection and iii) characterize the MPXV evolution by whole genome sequencing (WGS) during the outbreak occurred in Italy. Material and methodsThe study included 353 patients with a laboratory-confirmed diagnosis of MPXV infection screened in several clinical specimens in the period May 24th - September 1st, 2022. Viral isolation was attempted from different biological matrices and complete genome sequencing was performed for 61 MPXV strains. ResultsMPXV DNA detection was more frequent in the skin (94.4%) with the longest median time of viral clearance (16 days). The actively-replicating virus in cell culture was obtained for 123/377 (32.6%) samples with a significant higher viral quantity on isolation positive samples (20 vs 31, p < 0.001). The phylogenetic analysis highlighted the high genetic identity of the MPXV strains collected, both globally and within the Lombardy region. ConclusionSkin lesion is gold standard material and the high viral load and the actively-replicating virus observed in genital sites confirms that sexual contact plays a key role in the viral transmission.

Single-Dose Immunogenic DNA Vaccines Coding for Live-Attenuated Alpha- and Flaviviruses.

Single-dose, immunogenic DNA (iDNA) vaccines coding for whole live-attenuated viruses are reviewed. This platform, sometimes called immunization DNA, has been used for vaccine development for flavi- and alphaviruses. An iDNA vaccine uses plasmid DNA to launch live-attenuated virus vaccines in vitro or in vivo. When iDNA is injected into mammalian cells in vitro or in vivo, the RNA genome of an attenuated virus is transcribed, which starts replication of a defined, live-attenuated vaccine virus in cell culture or the cells of a vaccine recipient. In the latter case, an immune response to the live virus vaccine is elicited, which protects against the pathogenic virus. Unlike other nucleic acid vaccines, such as mRNA and standard DNA vaccines, iDNA vaccines elicit protection with a single dose, thus providing major improvement to epidemic preparedness. Still, iDNA vaccines retain the advantages of other nucleic acid vaccines. In summary, the iDNA platform combines the advantages of reverse genetics and DNA immunization with the high immunogenicity of live-attenuated vaccines, resulting in enhanced safety and immunogenicity. This vaccine platform has expanded the field of genetic DNA and RNA vaccines with a novel type of immunogenic DNA vaccines that encode entire live-attenuated viruses.

Current trends and new approaches for human norovirus replication in cell culture: a literature review.

Human norovirus (HuNoV) is one of the world's leading causes of acute gastroenteritis. At present, effective reproduction of the virus in cell cultures remains a challenge for virologists, as there is a lack of a permissive cell line that allows the entire viral life cycle to be reproduced. This is a barrier to the study of the HuNoV life cycle, its tropism, and virus-host interactions. It is also a major hurdle for the development of viral detection platforms, and ultimately for the development of therapeutics. The lack of an inexpensive, technically simple, and easily implemented cultivation method also negatively affects our ability to evaluate the efficacy of a variety of control measures (disinfectants, food processes) for human norovirus. In the process of monitoring this pathogen, it is necessary to detect infectious viral particles in water, food, and other environmental samples. Therefore, improvement of in vitro replication of HuNoV is still needed. In this review, we discuss current trends and new approaches to HuNoV replication in cell culture. We highlight ways in which previous research on HuNoV and other noroviruses has guided and influenced the development of new HuNoV culture systems and discuss the improvement of in vitro replication of HuNoV.

Inhibition of Cellular Factor TM6SF2 Suppresses Secretion Pathways of Hepatitis B, Hepatitis C, and Hepatitis D Viruses.

Chronic viral hepatitis is caused by hepatitis B virus (HBV), hepatitis C virus (HCV), or hepatitis D virus (HDV). Despite different replication strategies, all of these viruses rely on secretion through the host endoplasmic reticulum-Golgi pathway, providing potential host targets for antiviral therapy. Knockdown of transmembrane 6 superfamily member 2 (TM6SF2) in virus cell culture models reduced secretion of infectious HCV virions, HDV virions, and HBV subviral particles. Moreover, in a cohort of people with hepatitis B, a TM6SF2 polymorphism (rs58542926 CT/TT, which causes protein misfolding and reduced TM6SF2 in the liver) correlated with lower concentrations of subviral particles in blood, complementing our previous work showing decreased HCV viral load in people with this polymorphism. In conclusion, the host protein TM6SF2 plays a key role in secretion of HBV, HCV, and HDV, providing the potential for novel pan-viral agents to treat people with chronic viral hepatitis.

Investigating vulnerability of the conserved SARS-CoV-2 spike's heptad repeat 2 as target for fusion inhibitors using chimeric miniproteins

Inhibition of SARS-CoV-2 membrane fusion is a highly desired target to combat COVID-19. The interaction between the spike's heptad repeat (HR) regions 1 (HR1) and 2 (HR2) is a crucial step during the fusion process and these highly conserved HR regions constitute attractive targets for fusion inhibitors. However, the relative importance of each subregion of the long HR1-HR2 interface for viral inhibition remains unclear. Here, we designed, produced, and characterized a series of chimeric miniproteins that mimic two different half subdomains of HR1. The proteins were designed as single polypeptide chains that spontaneously fold into antiparallel trimeric helical bundles aimed at structurally imitate the molecular surface of each HR1 half subregion. All the miniproteins folded stably as helical structures and could bind complementary HR2 peptides with moderate affinity. However, only the miniproteins mimicking the N-terminal HR1 half subdomain, but not those imitating C-terminal one, could inhibit cell infection by SARS-COV-2 real viruses in cell cultures. Most interestingly, the inhibitory activity of the miniproteins correlated with their structural stability, but not with their relative binding affinity for HR2 peptides. These results are highly relevant for designing more focused and active fusion inhibitors targeting the highly conserved HR2 region of the Spike.

Antiviral effect of peptoids on hepatitis B virus infection in cell culture

Although antimicrobial peptides have been shown to inactivate viruses through disruption of their viral envelopes, clinical use of such peptides has been hampered by a number of factors, especially their enzymatically unstable structures. To overcome the shortcomings of antimicrobial peptides, peptoids (sequence-specific N-substituted glycine oligomers) mimicking antimicrobial peptides have been developed. We aimed to demonstrate the antiviral effects of antimicrobial peptoids against hepatitis B virus (HBV) in cell culture. The anti-HBV activity of antimicrobial peptoids was screened and evaluated in an infection system involving the HBV reporter virus and HepG2.2.15-derived HBV. By screening with the HBV reporter virus infection system, three (TM1, TM4, and TM19) of 12 peptoids were identified as reducing the infectivity of HBV, though they did not alter the production levels of HBs antigen in cell culture. These peptoids were not cytotoxic at the evaluated concentrations. Among these peptoids, TM19 was confirmed to reduce HBV infection most potently in a HepG2.2.15-derived HBV infection system that closely demonstrates authentic HBV infection. In cell culture, the most effective administration of TM19 was virus treatment at the infection step, but the reduction in HBV infectivity by pre-treatment or post-treatment of cells with TM19 was minimal. The disrupting effect of TM19 targeting infectious viral particles was clarified in iodixanol density gradient analysis. In conclusion, the peptoid TM19 was identified as a potent inhibitor of HBV. This peptoid prevents HBV infection by disrupting viral particles and is a candidate for a new class of anti-HBV reagents.

Experimental Medications Made with &lt;i&gt;Сetraria islandica&lt;/i&gt; Showing Antiviral Activity against Influenza A Virus

Background. To date, virologists have identified more than 25,000 influenza virus А serotypes, and their number will increase in the future. Therefore, the development of new antiviral drugs will always be relevant.The aim of the study is to obtain and test the chemical composition and antiviral activity of the lichen Cetraria islandica extracts against the influenza A virus.Material and methods. Samples of lichen Cetraria islandica (aqueous and ethanol extracts) were tested for toxic properties and antiviral activity against influenza A virus in MDCK cell culture.Results. Samples of aqueous and ethanol extracts of Cetraria islandica were obtained; their chemical composition was described. In MDCK cell culture, the extracts exhibited antiviral activity against human influenza virus А/H3N2 and avian influenza virus А/H5N1. When studying the mechanism of action of Cetraria islandica extracts, it was noted that Cetraria islandica samples possess pronounced antiviral properties against avian influenza A/chicken/Kurgan/05/2005 (H5N1) and human influenza A/Aichi/2/68 (H3N2) at the stage of their adsorption and reproduction.Conclusions. Samples of Cetraria islandica have antiviral activity at the stage of adsorption and reproduction of influenza A virus in MDCK cell culture. The ethanol extract shows a higher antiviral efficacy compared to the aqueous extract.

Detection of Human Adenovirus from Clinical Samples of Conjunctivitis by Real-time PCR: A Cross-sectional Descriptive Study

Introduction: Human Adenoviruses (HAdV) have been implicated in a variety of infections, including conjunctivitis, respiratory tract infections, genitourinary infections and gastroenteritis. Epidemic Keratoconjunctivitis (EKC) is a severe ocular surface infection strongly associated with HAdV, known to occur in widespread outbreaks. HAdV species B, D and E are associated with ocular manifestations ranging from simple follicular conjunctivitis (types 3, 4, 7) and pharyngoconjunctival fever (types 3, 7, 14) to the more severe EKC (types 8, 19, 37, 53, 54, 56 and 64). Viral cell cultures of conjunctival specimens help confirm adenovirus infection through the characteristic Cytopathic Effect (CPE) and Polymerase Chain Reaction (PCR) is the best standard method to diagnose viral conjunctivitis due to its sensitivity, accuracy and rapidity. Aim: To diagnose HAdV in clinically suspected cases of viral conjunctivitis using real-time PCR. To isolate HAdV in viral cell culture and confirm it by observing its characteristic CPE and performing adenoviral real-time PCR. Materials and Methods: A cross-sectional descriptive study was conducted from July 2023 to September 2023 at the state-level Virus Research and Diagnostic Laboratory (VRDL) at Bangalore Medical College and Research Institute (BMCRI), Bengaluru, Karnataka, India. A total of 45 conjunctival swab samples from patients with suspected viral conjunctivitis, who attended the Ophthalmology Outpatient Department (OPD) or were admitted to the wards, were included in the study. Conjunctival swab samples collected in Viral Transport Medium (VTM) were centrifuged at 3000 rpm for five minutes at 4°C. Real-time PCR was performed and samples positive for HAdV by real-time PCR were taken up for viral cell culture. Confirmatory PCR was conducted for samples showing CPEs in the cell line. The data collected were analysed using descriptive statistics. Results: The majority of patients in the present study were in the age group of 18-45 years, comprising 25 (56%) of the total patients. Out of 45 conjunctival samples tested, 8 samples were positive in adenovirus real-time PCR. All eight PCR-positive samples showed a CPE in viral cell culture on the A549 cell line. The study found PCR positivity in 8 samples (17.7%), while adenoviral recovery from cell culture was observed in 6 samples (13.3%). Conclusion: Real-time PCR has become the standard diagnostic procedure for detecting adenovirus conjunctivitis. Rapid and accurate diagnosis is key to interrupting the contagious spread of adenoviral conjunctivitis, along with timely treatment.