Viruses-Basel最新文献

Human immunodeficiency virus type 1 (HIV-1) continues to be a major global health burden. Combination antiretroviral therapy (cART) effectively abrogates HIV-1 replication and has transformed HIV-1 infection from a fatal to chronic disease. While ART can suppress viremia to undetectable levels in people living with HIV-1 (PWH), a small reservoir of cells infected with replication-competent HIV-1 persists and can lead to viral rebound upon ART interruption. This persistent HIV-1 reservoir can be quantified and characterized by measuring replication of infectious HIV-1 using a quantitative viral outgrowth assay (qVOA), or by measuring HIV-1 DNA, RNA, or protein levels as a proxy for the reservoir. Tools to quantify the reservoir in these distinct molecular compartments have been developed for HIV-1 subtype B, which is predominant in the Global North. However, non-B subtypes constitute the majority of HIV-1 infections worldwide. Here, we discuss the wide range of reservoir quantitation and characterization tools, explore their limitations, and, where applicable, their adaptations to non-B subtypes. We conclude that standardized tools should be used to characterize reservoir dynamics of HIV-1 B and non-B subtypes. These tests should be well-validated and accessible to all laboratories world-wide to be able to draw conclusions about subtype-specific reservoir dynamics.

Interferons (IFNs) are essential mediators of the innate immune response to viral infections. Among the type III IFNs, the role of IFN-λ4 in respiratory viral infections remains largely understudied. Respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) are clinically significant pneumoviruses that elicit divergent IFN responses in epithelial cells. Here, we investigate the virus-specific induction and antiviral activity of IFN-λ4 by HMPV and RSV infections. We demonstrate that RSV induces a limited expression of IFN-λ4, which is regulated by the expression of the NS1 protein. Furthermore, RSV and HMPV rely primarily on RIG-I for IFN-λ4 induction. Finally, we show that IFN-λ4 exerts antiviral activity against both viruses, with RSV displaying greater sensitivity. These findings highlight the antiviral role of IFN-λ4 to clinically relevant respiratory viruses.

The SARS-CoV-2 nucleocapsid protein (Np) is essential for viral RNA replication and genomic RNA packaging. Phosphorylation of Np within its central Ser-Arg-rich (SRR) linker is proposed to modulate these functions. To gain mechanistic insights into these distinct roles, we performed in vitro biophysical and biochemical studies using recombinantly expressed ancestral Np and phosphomimetic SRR variants. Limited-proteolysis showed minor cleavage differences between wild-type (WT) and phosphomimetic Np, but no major structure or stability changes in the N- and C-terminal domains were observed by circular dichroism spectroscopy and differential scanning fluorimetry, respectively. Mass photometry (MP) revealed that WT Np dimerized more readily than phosphomimetic variants. Crosslinking-MP showed that WT Np formed discrete complexes on viral 5' UTR stem-loop (SL) 5 RNA, whereas phosphomimetic Np assembled preferentially on SL1-4. WT Np bound non-specifically to all RNAs tested primarily via hydrophobic interactions, whereas phosphomimetic Np showed selectivity for SARS-CoV-2-derived RNAs despite binding more electrostatically. A major difference was observed in the binding kinetics; WT Np compacted and irreversibly bound single-stranded DNA, whereas phosphomimetic Np displayed reduced compaction and fast on/off binding kinetics. These mechanistic insights support a model where phosphorylated Np functions in RNA replication and chaperoning, while non-phosphorylated Np facilitates genomic RNA packaging. The findings also help to explain infectivity differences and clinical outcomes associated with SRR linker variants.

Tick-borne encephalitis virus (TBEV) causes tick-borne encephalitis (TBE), a severe disease of the human central nervous system. Currently, the data on the genetic variants of TBEV in Kyrgyzstan are practically absent. Therefore, the aim of this study was to analyze and describe the genetic diversity of TBEV in this region. The complete genome sequences of seven TBEV strains from the collection of the Scientific Centre for Family Health and Human Reproduction Problems (Irkutsk, Russia) were determined. These strains, isolated from Ixodes persulcatus ticks from Kyrgyzstan, were sequenced using the next generation sequencing approach on a MiSeq high-performance sequencer (Illumina, San Diego, CA, USA). A molecular genetic analysis of the obtained sequences, along with sequences of two previously isolated TBEV strains from Kyrgyzstan available in the GenBank database, demonstrated that the Siberian subtype of three genetic lineages (Zausaev, Vasilchenko and Bosnia) is predominantly distributed in Kyrgyzstan. The Far Eastern subtype of TBEV is also present. To date, this location probably represents the southernmost boundary of these TBEV subtypes' ranges.

Filoviruses, including Ebola (EBOV) and Marburg (MARV) viruses, are zoonotic pathogens that cause severe hemorrhagic fever in humans, with mortality rates reaching up to 90%. Filovirus egress and spread are driven by the viral matrix protein VP40 and regulated both positively and negatively by a growing number of specific host interactors. Here, we identify tetraspanin protein CD9, a plasma membrane organizing and scaffolding protein, as playing a role in facilitating efficient egress of EBOV and MARV. Indeed, we observed a significant decrease in viral egress of VLPs and live filoviruses from CD9-KD cells as compared to that from WT cells. Moreover, exogenous expression of CD9 rescued egress of VP40 VLPs close to WT levels in the CD9-KD cells. These findings identify tetraspanin CD9 as a positive regulator of filovirus egress, and thus CD9 may represent a potential new target for antiviral therapies targeting the late stage of the filovirus lifecycle.

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Mammarenaviruses (MaAv) cause persistent infection in their natural rodent hosts across the world and, via zoonotic events, can cause severe disease in humans. Thus, the MaAv Lassa virus (LASV) in Western Africa and the Junin virus (JUNV) in the Argentinean Pampas cause hemorrhagic fever diseases with significant case fatality rates in their endemic regions. In addition, the globally distributed MaAv lymphocytic choriomeningitis virus (LCMV) is an underrecognized human pathogen of clinical significance capable of causing devastating infections in neonates and immunocompromised individuals. Despite their impact on human health, there are currently no FDA-approved vaccines or specific antiviral treatments for MaAv infections. Existing anti-MaAv therapies are limited to the off-label use of ribavirin, whose efficacy remains controversial; hence, the development of novel therapeutics to combat human pathogenic MaAv is vital. We employed a high-throughput cell-based infection assay to screen the Pandemic Response Box, a collection of 400 diverse compounds with established antimicrobial activity, for MaAv inhibitors. We identified Ro-24-7429, an antagonist of the HIV-1 Tat protein and RUNX family transcription factor 1 inhibitor; WO 2006118607 A2, a dihydroorotate dehydrogenase inhibitor; and verdinexor, a novel selective inhibitor of nuclear export (SINE) targeting the XPO1/CRM1, as potent anti-MaAv compounds. Consistent with their distinct validated targets, verdinexor and WO 2006118607 A2 exhibited very strong synergistic antiviral activity when used in combination therapy. Our findings pave the way for the development of verdinexor as a potent host-directed antiviral against MaAv, which could be integrated into the development of combination therapy with direct- or host-acting antivirals to combat human pathogenic MaAv.

The limited ability of the immune system to infiltrate solid tumors, attributed to the immunosuppressive tumor microenvironment (TME), remains a significant challenge in cancer therapy oncolytic adenovirus (OAd) that can directly kill tumor cells in addition to inducing both innate and adaptive immune responses. Therefore, the use of OAd to treat tumors is an appealing approach. In this study, we engineered an OAd armed with a human granulocyte-macrophage colony-stimulating factor (GM-CSF), controlled by the E2F promoter, Ad5/3-E2F-d24-GM-CSF (named OAd-Z1). The antitumor activity of OAd was tested in vitro and in vivo. These findings demonstrated that OAd expressed GM-CSF, replicated effectively in tumor cells, inhibited tumor growth, activated the de novo antitumor response, promoted apoptosis and immunogenic cell death in tumor cells, and increased cytokine and chemokine production both in vitro and in vivo. Additionally, OAd demonstrated an abscopal effect and stimulated T lymphocyte infiltration in vivo. Our findings demonstrate that OAd-Z1 represents promising immunotherapeutic candidates for lung cancer, with the potential to enhance systemic antitumor immunity.

Human papillomavirus (HPV) vaccination may eventually eradicate oncogenic vaccine-targeted HPVs but only with a strategy that also protects unvaccinated individuals. We compared the impact of gender-neutral and girls-only vaccination strategies on the indirect and direct protection of unvaccinated and vaccinated young women against HPV16/18 infection using HPV16/18 seropositivity and PCR positivity 3-7 years post vaccination as the outcome measure. A total of 33 Finnish communities were randomized to one of three vaccination strategies: bivalent gender-neutral HPV vaccination (Arm A), girls-only HPV vaccination (Arm B), or control hepatitis B vaccination (Arm C). All individuals born between 1992 and 1995 and residing in these communities (n = 80,272) were invited to participate. Overall, 11,662 males and 20,513 females consented, corresponding to vaccination coverages of 25% and 45%, respectively, in 2007-2009. Between 2010 and 2014, 11,396 cervical samples were collected from 18-year-old participants and subjected to high-throughput PCR-based HPV genotyping. In addition, serum samples were obtained from 8022 unvaccinated women under 23 years of age residing in Arm A (n = 2657), Arm B (n = 2691), or Arm C (n = 2674) communities during the pre-vaccination (2005-2010) and post-vaccination (2011-2016) periods. To assess indirect vaccine effects using PCR and serological outcomes in unvaccinated women, we compared reductions in HPV16/18 prevalence from baseline within the gender-neutral and girls-only vaccination arms, using the control arm as a reference. A significant decrease in seroprevalence between the pre- and post-vaccination periods was detected in the gender-neutral communities for both HPV16 (seroprevalence ratio = 0.64) and HPV18 (0.72), whereas no comparable reductions were observed in the girls-only or control communities. In contrast, a significant reduction in HPV18 PCR-based prevalence from baseline to the post-vaccination period was observed in both the gender-neutral (0.32) and girls-only (0.61) communities. However, after accounting for ratios of seroprevalence rations for secular trends, the corresponding decrease in HPV18 seroprevalence was no longer statistically significant. Vaccine efficacy (VE) in Arm A or Arm B versus Arm C of vaccinated women measured the direct protection of vaccinated women by vaccination strategy. HPV16/18 VEs varied between 89% and 96% with some indication of herd effect against HPV18. Robust effectiveness of vaccination against PCR-confirmed cervical HPV16/18 infections, along with rapid indirect protection against HPV16/18 and HPV18 infections, was evident even with vaccination reaching only 25% and 45% coverage. Our results suggest that vaccine efficacy and herd effect induced by gender-neutral 2vHPV vaccination sets the stage for comprehensive HPV eradication, including the unvaccinated in the vaccinated communities.

In the original publication [...].