Viruses-Basel最新文献

This article investigates the role of local fauna in Western Kazakhstan as potential reservoirs of the camelpox virus (CMLV). The study emphasizes analyzing possible sources and transmission pathways of the virus using polymerase chain reaction (PCR) and serological methods, including virus neutralization tests and enzyme-linked immunosorbent assays (ELISA). Samples were collected from both young and adult camels, as well as rodents, ticks and blood-sucking insects in the Mangystau and Atyrau regions. The PCR results revealed the absence of viral DNA in rodents, ticks and blood-sucking insects; also, the ELISA test did not detect specific antibodies in rodents. These findings suggest that these groups of fauna likely do not play a significant role in the maintenance and spread of CMLV. Consequently, the primary sources of transmission are likely other factors, potentially including the camels themselves. The study's results indicate the need to reassess current hypotheses regarding infection reservoirs and to explore alternative sources to enhance strategies for the control and prevention of the camelpox virus.

Animal models that are susceptible to SARS-CoV-2 infection and develop clinical signs like human COVID-19 are desired to understand viral pathogenesis and develop effective medical countermeasures. The golden Syrian hamster is important for the study of SARS-CoV-2 since hamsters are naturally susceptible to SARS-CoV-2. However, infected hamsters show only limited clinical disease and resolve infection quickly. In this study, we describe development of human angiotensin-converting enzyme 2 (hACE2) transgenic hamsters as a model for COVID-19. During development of the model for SARS-CoV-2, we observed that different hACE2 transgenic hamster founder lines varied in their susceptibility to SARS-CoV-2 lethal infection. The highly susceptible hACE2 founder lines F0F35 and F0M41 rapidly progress to severe infection and death within 6 days post-infection (p.i.). Clinical signs included lethargy, weight loss, dyspnea, and mortality. Lethality was observed in a viral dose-dependent manner with a lethal dose as low as 1 × 10^0.15 CCID₅₀. In addition, virus shedding from highly susceptible lines was detected in oropharyngeal swabs on days 2-5 p.i., and virus titers were observed at 10^5.5-6.5 CCID₅₀ in lung and brain tissue by day 4 p.i.. Histopathology revealed that infected hACE2-hamsters developed rhinitis, tracheitis, bronchointerstitial pneumonia, and encephalitis. Mortality in highly susceptible hACE2-hamsters can be attributed to neurologic disease with contributions from the accompanying respiratory disease. In contrast, virus challenge of animals from less susceptible founder lines, F0M44 and F0M51, resulted in only 0-20% mortality. To demonstrate utility of this SARS-CoV-2 infection model, we determined the protective effect of the TLR3 agonist polyinosinic-polycytidylic acid (Poly (I:C)). Prophylactic treatment with Poly (I:C) significantly improved survival in highly susceptible hACE2-hamsters. In summary, our studies demonstrate that hACE2 transgenic hamsters differ in their susceptibility to SARS-CoV-2 infection, based on the transgenic hamster founder line, and that prophylactic treatment with Poly (I:C) was protective in this COVID-19 model of highly susceptible hACE2-hamsters.

Cervical cancer cases continue to rise despite all the advanced screening and preventative measures put in place, which include human papillomavirus (HPV) vaccination. These soaring numbers can be attributed to the lack of effective anticancer drugs against cervical cancer; thus, repurposing the human immunodeficiency virus protease inhibitors is an attractive innovation. Therefore, this work was aimed at evaluating the potential anticancer activities of HIV-PIs against cervical cancer cells. The MTT viability assay was used to evaluate the effect of HIV protease inhibitors on the viability of cervical cancer cells (HeLa) and non-cancerous cells (HEK-293). Further confirmation of the MTT assay was performed by confirming the IC₅₀s of these HIV protease inhibitors on cervical cancer cells and non-cancerous cells using the Muse™ Count and Viability assay. To confirm the mode of death induced by HIV protease inhibitors in the HPV-associated cervical cancer cell line, apoptosis was performed using Annexin V assay. In addition, the Muse™ Cell Cycle assay was used to check whether the HIV protease inhibitors promote or halt cell cycle progression in cervical cancer cells. HIV protease inhibitors did not affect the viability of non-cancerous cells (HEK-293), but they decreased the viability of HeLa cervical cancer cells in a dose-dependent manner. HIV protease inhibitors induced apoptosis in HPV-related cervical cancer cells. Furthermore, they also induced cell cycle arrest, thus halting cell cycle progression. Therefore, the use of HIV drugs, particularly HIV-1 protease inhibitors, as potential cancer therapeutics represents a promising strategy. This is supported by our study demonstrating their anticancer properties, notably in HPV-associated cervical cancer cell line.

Modified vaccinia Ankara (MVA) virus is a widely used vaccine platform, making accurate titration essential for vaccination studies. However, the current plaque forming unit (PFU) assay, the standard for MVA titration, is prone to observer bias and other limitations that affect accuracy and precision. To address these challenges, we developed a new flow cytometry-based quantification method using a highly specific monoclonal antibody (mAb) for the detection of MVA-infected cells, as a more accurate titration assay. Through previous work, we serendipitously identified three MVA-specific hybridoma antibody clones, which we characterized through ELISA, immunoblot, and flow cytometry, confirming their specificity for MVA. Sequencing confirmed that each antibody was monoclonal, and mass spectrometry results revealed that all mAbs target the MVA cell surface binding protein (CSBP, MVA105L). We next optimized the titration protocol using the most effective mAb, 33C7 by refining culture conditions and staining protocols to enhance sensitivity and minimize background. Our optimized method demonstrated superior sensitivity, reliability, and reduced processing time when compared with the traditional PFU assay, establishing it as a more accurate and efficient approach for MVA titration.

Erwinia amylovora, the causative agent of fire blight, causes significant economic losses for farmers worldwide by inflicting severe damage to the production and quality of plants in the Rosaceae family. Historically, fire blight control has primarily relied on the application of copper compounds and antibiotics, such as streptomycin. However, the emergence of antibiotic-resistant strains and growing environmental concerns have highlighted the need for alternative control methods. Recently, there has been a growing interest in adopting bacteriophages (phages) as a biological control strategy. Phages have demonstrated efficacy against the bacterial plant pathogen E. amylovora, including strains that have developed antibiotic resistance. The advantages of phage therapy includes its minimal impact on microbial community equilibrium, the lack of a detrimental impact on plants and beneficial microorganisms, and its capacity to eradicate drug-resistant bacteria. This review addresses recent advances in the isolation and characterization of E. amylovora phages, including their morphology, host range, lysis exertion, genomic characterization, and lysis mechanisms. Furthermore, this review evaluates the environmental tolerance of E. amylovora phages. Despite their potential, E. amylovora phages face certain challenges in practical applications, including stability issues and the risk of lysogenic conversion. This comprehensive review examines the latest developments in the application of phages for controlling fire blight and highlights the potential of E. amylovora phages in plant protection strategies.

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Nonhuman primate (NHP) studies that utilize simian immunodeficiency virus (SIV) to model human immunodeficiency virus (HIV-1) infection have proven to be powerful, highly informative research tools. However, there are substantial differences between SIV and HIV-1. Accordingly, there are numerous research questions for which SIV-based models are not well suited, including studies of certain aspects of basic HIV-1 biology, and pre-clinical evaluations of many proposed HIV-1 treatment, prevention, and vaccination strategies. To overcome these limitations of NHP models of HIV-1 infection, several groups have pursued the derivation of a minimally modified HIV-1 (mmHIV-1) capable of establishing pathogenic infection in macaques that authentically recapitulates key features of HIV-1 in humans. These efforts have focused on three complementary objectives: (1) engineering HIV-1 to circumvent species-specific cellular restriction factors that otherwise potently inhibit HIV-1 in macaques, (2) introduction of a C chemokine receptor type 5 (CCR5)-tropic envelope, ideally that can efficiently engage macaque CD4, and (3) correction of gene expression defects inadvertently introduced during viral genome manipulations. While some progress has been made toward development of mmHIV-1 variants for use in each of the three macaque species (pigtail, cynomolgus, and rhesus), model development progress has been most promising in pigtail macaques (PTMs), which do not express an HIV-1-restricting tripartite motif-containing protein 5 α (TRIM5α). In our work, we have derived a CCR5-tropic mmHIV-1 clone designated stHIV-A19 that comprises 94% HIV-1 genome sequence and replicates to high acute-phase titers in PTMs. In animals treated with a cell-depleting CD8α antibody at the time of infection, stHIV-A19 maintains chronically elevated plasma viral loads with progressive CD4+ T-cell loss and the development of acquired immune-deficiency syndrome (AIDS)-defining clinical endpoints. However, in the absence of CD8α+ cell depletion, no mmHIV-1 model has yet displayed high levels of chronic viremia or AIDS-like pathogenesis. Here, we review mmHIV-1 development approaches, the phenotypes, features, limitations, and potential utility of currently available mmHIV-1s, and propose future directions to further advance these models.

The virions of plant viruses and their structurally modified particles (SP) represent valuable platforms for recombinant vaccine epitopes and antitumor agents. The possibility of modifying their surface with biological compounds makes them a tool for developing medical biotechnology applications. Here, we applied a new type of SP derived from virions and virus-like particles (VLP) of Alternanthera mosaic virus (AltMV) and well-studied SP from Tobacco mosaic virus (TMV). We have tested the ability of SP from AltMV (AltMV SP_V) and TMV virions also as AltMV VLP to bind to and penetrate Ewing sarcoma cells. The adsorption properties of AltMV SP_V and TMV SP are greater than those of the SP from AltMV VLP. Compared to normal cells, AltMV SP_V adsorbed more effectively on patient-derived sarcoma cells, whereas TMV SP were more effective on the established sarcoma cells. The AltMV SP_V and TMV SP were captured by all sarcoma cell lines. In the established Ewing sarcoma cell line, the effectiveness of AltMV SP_V penetration was greater than that of TMV SP. The usage of structurally modified plant virus particles as a platform for drugs and delivery systems has significant potential in the development of anticancer agents.

According to the WHO, more than 90,000 cases of mpox have been reported since the 2022 worldwide outbreak, which resulted in 167 deaths, while a new outbreak in Africa since 2023 has resulted in over 18,000 cases and 617 deaths. Mpox is a zoonosis caused by the monkeypox virus, a double-stranded DNA virus belonging to the Orthopoxvirus genus, which causes smallpox-like illness. Until 2022, cases were predominately located in West and Central Africa, with only sporadic cases and outbreaks reported in other parts of the world. During the 2022 outbreak, the primary mode of transmission was sexual contact among men who have sex with men. The changing epidemiology of mpox resulted in new disease phenotypes and populations at risk, disproportionally affecting people who live with HIV. Commonly presenting as a mild, self-limiting illness, mpox can cause severe and protracted disease in people with HIV with a CD4 count < 200 cell/mm³. The global emergence of mpox that followed and intersected with COVID-19 mobilized the scientific community and healthcare stakeholders to provide accurate diagnostics, preventive vaccines and treatment to those most affected. Despite existing gaps, this rapid response helped to contain the outbreak, but challenges remain as new variants emerge. Preparedness and readiness to respond to the next outbreak is crucial in order to minimize the impact to the most vulnerable.

Adeno-associated viruses (AAV) are widely used as delivery vectors in clinical trials for in vivo gene therapy due to their unique features. Göttingen minipigs are a well-established animal model for several diseases and can be used for the efficacy and safety testing of AAV-based gene therapy. Pre-existing antibodies against AAV may influence the results of testing and, therefore, the animals should be tested for the presence of antibodies against relevant AAV serotypes. The detection of AAVs in pigs may be also important for the virus safety of xenotransplantation. In this study, we screened Göttingen minipigs from Ellegaard Göttingen Minipigs A/S, Denmark, and Marshall BioResources, USA, for antibodies against AAV1, AAV2, AAV6, AAV9 serotypes. Of the 20 animals tested, 18 had no neutralizing antibodies for all AAVs tested, none had antibodies against AAV9, only one had antibodies against AAV6, and the titers of antibodies against AAV1 and AAV2 were less than 1:100, with two exceptions. For total binding IgG, more individuals showed positivity for all the tested serotypes but, in general, the levels were low or zero. Three animals had no antibodies at all against the AAVs tested. Therefore, Göttingen minipigs could be considered an attractive animal model for gene therapy studies. Since some animals were negative for all AAVs tested, these may be selected and used as donor animals for xenotransplantation.