Journal: Journal of Virology

Article Title: Potent in vitro synergistic antiviral effects of the pan-coronavirus fusion inhibitor EK1 in combination with RBD-specific antibodies or M pro inhibitors

doi: 10.1128/jvi.00076-26

Figure Lengend Snippet: Cytotoxicity of EK1, antibodies, and M pro inhibitors on Caco-2 and RD cells. ( A–G ) Cytotoxicity of EK1, PF-07321332, RAY1216, S-217622, G7, bn03, and control on Caco-2 cells. ( H–L ) Cytotoxicity of EK1, PF-07321332, RAY1216, S-217622, and control on RD cells. Data represent mean ± SD from three independent experiments ( n = 3).

Article Snippet: The small-molecule M pro inhibitors nirmatrelvir (PF-07321332), RAY1216, and ensitrelvir (S-217622) were purchased from MedChemExpress (Shanghai, China).

Techniques: Control

Journal: Journal of Virology

Article Title: Potent in vitro synergistic antiviral effects of the pan-coronavirus fusion inhibitor EK1 in combination with RBD-specific antibodies or M pro inhibitors

doi: 10.1128/jvi.00076-26

Figure Lengend Snippet: Synergistic inhibition of authentic SARS-CoV-2 BA.2 and HCoV-OC43 by dual antiviral combinations. ( A ) Crystal structure of the M pro active site (PDB ID: 7CAM ). The protease is shown as a semi-transparent surface in gray, with the inhibitor-binding cleft highlighted in green. ( B ) Binding sites of M pro with PF-07321332 (PDB ID: 7VH8) in green, RAY1216 (PDB ID: 8IGN ) in yellow, and S-217622 (PDB ID: 8HEF ) in orange. ( C–H ) Dose-response analyses of the fusion inhibitor EK1 in combination with three distinct M pro inhibitors against authentic SARS-CoV-2 BA.2 ( C–E ) and HCoV-OC43 ( F–H ). In each panel, EK1 and the respective M pro inhibitor were tested both individually and as fixed-ratio combinations (molar ratios: PF-07321332, 20:3 for BA.2 and 25:4 for OC43; RAY1216, 4:1 for BA.2 and 25:1 for OC43; S-217622, 4:1 for BA.2 and 25:1 for OC43). Viral inhibition was quantified by fluorescent plaque assay (BA.2), and cell viability was assessed using the cell counting kit-8 (CCK-8) assay (OC43) at 48 h post-infection. Data represent mean ± SD from three independent experiments ( n = 3).

Article Snippet: The small-molecule M pro inhibitors nirmatrelvir (PF-07321332), RAY1216, and ensitrelvir (S-217622) were purchased from MedChemExpress (Shanghai, China).

Techniques: Inhibition, Binding Assay, Plaque Assay, Cell Counting, CCK-8 Assay, Infection

Journal: Journal of Virology

Article Title: Potent in vitro synergistic antiviral effects of the pan-coronavirus fusion inhibitor EK1 in combination with RBD-specific antibodies or M pro inhibitors

doi: 10.1128/jvi.00076-26

Figure Lengend Snippet: Conceptual framework for combinatorial antiviral trident therapy. Schematic overview illustrating the underlying rationale and mechanistic logic of multi-agent intervention against coronavirus infection. By simultaneously targeting discrete stages of the viral life cycle, including membrane fusion (EK1, PDB ID: 7C53 ), receptor engagement (neutralizing antibodies G7 (PDB ID: 8YWE) and nanobodies bn03 (PDB ID: 7WHJ) against RBD), and viral replication (M pro inhibitors: PF-07321332 [PDB ID: 7VH8 ]; RAY1216 [PDB ID: 8IGN ]; S-217622 [PDB ID: 8HEF ]), this approach achieves potent, synergistic inhibition of viral entry, genome replication, and progeny virion production. Dual- or triple-agent combinations permit dose reduction of individual compounds, thereby minimizing toxicity and cost, while curtailing the emergence of resistant variants through multifaceted blockade. Trident therapy defines a modular platform for rapid deployment of broad-spectrum antivirals against SARS-CoV-2 and future zoonotic coronaviruses.

Article Snippet: The small-molecule M pro inhibitors nirmatrelvir (PF-07321332), RAY1216, and ensitrelvir (S-217622) were purchased from MedChemExpress (Shanghai, China).

Techniques: Infection, Membrane, Inhibition