The Rift Valley fever virus (RVFV) is an arthropod-borne virus that can not only cause severe disease in domestic animals but also in humans. However, the licensed vaccines or available therapeutics for humans do not exist. Here, we report two Gn-specific neutralizing antibodies (NAbs), isolated from a rhesus monkey immunized with recombinant human adenoviruses type 4 expressing Rift Valley fever virus Gn and Gc protein (rHAdV4-GnGcopt). The two NAbs were both able to protect host cells from RVFV infection. The interactions between NAbs and Gn were then characterized to demonstrate that these two NAbs might preclude RVFV glycoprotein rearrangement, hindering the exposure of fusion loops in Gc to endosomal membranes after the virus invades the host cell. The target region for the two NAbs is located in the Gn domain III, implying that Gn is a desired target for developing vaccines and neutralizing antibodies against RVFV.

Influenza A virus pandemics pose a persistent global health threat, and emerging antiviral resistance underscores the critical importance of developing novel broad-spectrum therapeutic agents. Building on licorice’s (Glycyrrhiza spp.) historical use in traditional Chinese medicine for respiratory infections—as documented in the Chinese Guidelines for Diagnosis and Treatment of Influenza—and its demonstrated anti-SARS-CoV-2 activity, we identified licoflavone B as a potent anti-influenza agent, bridging ethnopharmacological knowledge with mechanistic validation. In this study, we identified licoflavone B, a natural flavonoid derived from licorice (Glycyrrhiza spp.), as a potent inhibitor of diverse influenza viruses, including multiple influenza A subtypes and type B virus. Mechanistic studies revealed that licoflavone B selectively targets the viral RNA-dependent RNA polymerase (RdRp), effectively suppressing viral replication. The compound exhibits a favorable selectivity index (SI = 14.9–29.9), indicating a promising therapeutic window. Molecular docking simulations identified potential binding interactions between licoflavone B and regions of the RdRp complex, which were further validated by dose-dependent inhibition of viral nucleoprotein (NP) and polymerase subunit PB2 expression in Western blot and immunofluorescence assays. In addition, licoflavone B maintained broad-spectrum antiviral activity against multiple influenza strains, including H1N1 (A/Puerto Rico/8/34), H3N2 (A/Darwin/9/2021), and a clinical influenza B isolate (B/Beijing/ZYY-B18/2018). These findings position licoflavone B as a promising lead compound for developing next-generation, broad-spectrum antiviral therapies against influenza and potentially other viruses.

Introduction: Human adenovirus serotype 4 (HAdV-4) is an epidemic pathogen associated with severe acute respiratory disease (ARD) in both pediatric and adult populations. Currently, no available vaccine or therapeutic interventions specifically targeting adenoviruses are available.Methods: In this study, we isolated peripheral blood mononuclear cells (PBMCs) from HAdV-4 infected donors and generated fully human monoclonal antibodies using single-cell PCR technology. The antibodies were first characterized for their neutralization efficacy both in vitro and in vivo. Subsequently, we predicted key functional residues through structural modeling of antigen-antibody complexes and validated their roles via mutagenesis studies. Finally, the mechanism of intracellular neutralization of antibodies was explored.Results: Through systematic screening, we successfully isolated seven antibodies with specific binding activity, among which monoclonal antibodies (mAbs) 2CF4 and 4AC3 exhibited potent neutralizing capacity against HAdV-4. Notably, we modeled adenoviral lethality using Stat1^-/- transgenic mice, mAb 2CF4 conferred full protection against HAdV-4 infection in Stat1^-/- transgenic mice. We identified critical amino acid residues, R99, R102 and T104 aa, of mAb 2CF4 by structural prediction of the antigen-antibody complex. Furthermore, the mAb 2CF4 neutralize the HAdV-4 through the interaction with the widely expressed cytoplasmic Fc-binding protein TRIM21.Discussion: Overall, mAb 2CF4 represents a promising candidate for safe and effective prophylactic and therapeutic strategies against HAdV-4 infection.

Telomerase, crucial for maintaining telomere integrity and genomic stability, is typically silenced in somatic cells with advancing age. In this study, we identify circHERC1 as a regulator of telomerase reverse transcriptase (TERT) transcription. Specifically, circHERC1 binds to the TERT promoter, facilitating the recruitment of RNA polymerase II and c-Fos, thereby activating TERT expression. Notably, circHERC1 expression exhibits a decline with age, which correlates with reduced telomerase activity. Restoration of circHERC1 expression enhances telomerase activity, promotes telomere elongation, and reverses aging-associated phenotypes. Furthermore, delivery of circHERC1 using adeno-associated virus vectors or extracellular vesicles effectively restores telomerase activity, preserves telomere integrity, and mitigates senescence. This intervention leads to improvements in cognitive function, physical performance, and a reduction in inflammation. These findings highlight the important role of circHERC1 in telomerase regulation and the aging process, positioning it as a potential therapeutic target for antiaging interventions.

Crimean-Congo hemorrhagic fever virus (CCHFV) is a highly pathogenic tick-borne virus that causes severe hemorrhagic fever with high mortality rates in humans. No licensed vaccines or efficacious antiviral therapies are currently available. Here, we identified seven heavy chain antibodies targeting CCHFV Gc, which consist of heavy-chain variable domain (VHH) fused to human IgG1 Fc region (VHH-Fc). These VHH-Fc antibodies exhibited neutralizing activity against both recombinant vesicular stomatitis virus (VSV)-vectored CCHFV pseudoviruses and CCHFV transcription- and entry-competent virus-like particles (tecVLPs). Among these, N025 achieved the most potent pseudovirus neutralization, while N013 showed remarkable efficacy in tecVLP systems, with IC₅₀ values of 22.7 ng/mL and 33.0 ng/mL, respectively. AlphaFold3 structural predictions revealed that all characterized VHH-Fc antibodies target epitopes within Domain II of the Gc protein, with partial or complete overlap with the fusion loop region. Alanine scanning mutagenesis confirmed the functional significance of these epitopes, with N013 showing the highest binding energy change (ΔΔG = 25.36 kcal/mol) and moderate competition with a known fusion loop-targeting antibody. Sequence conservation analysis across representative CCHFV strains from different genetic lineages demonstrated complete conservation of the N013 and N025 epitopes, suggesting potential for broad-spectrum neutralizing activity. Together, our findings provide a novel strategy for developing CCHFV therapeutics and identify promising antibody candidates that could inform future broad-spectrum antiviral development efforts.