Journal: npj Viruses

Article Title: K5 polysaccharides inhibit SARS-CoV-2 infection by preventing spike-proteolytic priming

doi: 10.1038/s44298-025-00163-4

Figure Lengend Snippet: a Representative images of syncytia formation assay in VeroE6 cells upon treatment (350 µM) with K5 compounds. Scale bar: 50 µm. b Number of nuclei involved in syncytia formation is higher in Wuhan-Hu-1 spike-positive cells than in Omicron BA.1 spike-positive cells. c Effect of K5 compounds on syncytia formation induced by Wuhan-Hu-1 spike. d Effect of K5 compounds on syncytia formation induced by Omicron BA.1 spike. Only spike-positive cells were quantified. Data of four (Wuhan-Hu-1) and three (Omicron BA.1) independent experiments. Values are mean ± sd. P values determined by Welch’s t-test: * P < 0.05; ** P < 0.005.

Article Snippet: Reagents and materials were used as received, unless otherwise mentioned, and were purchased from the following: Human recombinant SARS-CoV-2 Wuhan-Hu-1 spike His-Tag protein and RBD from Sino Biological (#40592-V08B); ACE2 from Acrobiosystem (#AC2-H52H8); Bovine Serum Albumin (BSA) from Merck (#810037); Human recombinant furin from OriGene Technologies Inc. (#TP304279M); Conventional heparin (13.6 kDa - purity ≥95%) from a commercial batch of unfractionated sodium heparin from Laboratori Derivati Organici S.p.A. (#9041-08-1).

Techniques: Tube Formation Assay

Journal: npj Viruses

Article Title: K5 polysaccharides inhibit SARS-CoV-2 infection by preventing spike-proteolytic priming

doi: 10.1038/s44298-025-00163-4

Figure Lengend Snippet: VeroE6 cells or A549 ACE2+ cells were treated with increasing concentrations of heparin, K5, K5OSH, and K5NOSH. a , b The cells remained viable in the presence of heparin and the K5 compounds as evaluated by measuring the ATP levels. VeroE6 or A549 ACE2+ cells were infected with the B.1 c , d or Omicron BA.1 e , f isolates in the presence or the absence of increasing concentrations of heparin, K5, K5OSH, and K5NOSH. Infection was reduced in a concentration-dependent manner as shown by the percentage of plaque reduction compared to SARS-CoV-2 alone. Data are presented as the mean value ± standard error of three independent replicates. * P < 0.05; ** P < 0.005.

Article Snippet: Reagents and materials were used as received, unless otherwise mentioned, and were purchased from the following: Human recombinant SARS-CoV-2 Wuhan-Hu-1 spike His-Tag protein and RBD from Sino Biological (#40592-V08B); ACE2 from Acrobiosystem (#AC2-H52H8); Bovine Serum Albumin (BSA) from Merck (#810037); Human recombinant furin from OriGene Technologies Inc. (#TP304279M); Conventional heparin (13.6 kDa - purity ≥95%) from a commercial batch of unfractionated sodium heparin from Laboratori Derivati Organici S.p.A. (#9041-08-1).

Techniques: Infection, Concentration Assay

Journal: iScience

Article Title: T cell epitope mapping reveals immunodominance of evolutionarily conserved regions within SARS-CoV-2 proteome

doi: 10.1016/j.isci.2025.113044

Figure Lengend Snippet: Adaptive immune recognition of SARS-CoV-2 variants (A) Antibody reactivity from vaccinated (before vaccination [V0, n = 14], 14 days after 1st dose [V1D14, n = 15], 7 days after 2nd dose [V2D7, n = 12] and 14 days after 2nd dose [V2D14, n = 13]), convalescent (conv, n = 19), or pre-COVID-19 (control, n = 1) serum to RBD were assessed by Luminex antibody binding assay where MagPlex-C microspheres were conjugated to recombinant wild-type (WT, Wuhan-1) and mutant RBD constructs (Alpha [N501Y], Beta [N501Y/K417N/E484K], and Gamma [N501Y/K417T/E484K] with mean fluorescence intensity (MFI) used as a readout for binding affinity. (B) Summary of ELISPOT data: peripheral blood mononuclear cells (PBMCs, 2 × 10 5 cells/well) from vaccinated donors (V2D14, n = 8) or from convalescent patients ( n = 5) were stimulated with pooled peptides covering the mutations found in Alpha, Beta, and Gamma variants (listed in (E)) or the corresponding WT sequences for 24 h and IFN-γ secretion was measured by ELISPOT. Average spot numbers per 2 × 10 5 cells were demonstrated after background subtraction. (C) V2D14 T cells from vaccinated donors ( n = 12) were stimulated with variant or WT peptide pools and expanded prior to being re-stimulated with either the initial stimulation peptide pool (WT→WT, Mut→Mut) or the variant pool to measure cross-reactivity (WT→Mut). Antigen-specific cytokine production by expanded T cell subsets, CD4 + or CD8 + , was measured by intracellular staining by flow cytometry. (D) Bars show Bayesian information criterion (BIC) values for different models of T cell reactivity shown in C, where lower BIC is better. The basic model includes the effect of peptide pool stimulations and WT-Mutant peptide cross-reactivity. Different peptide dominance models are shown on the y axis, which correspond to the 9mer aggregation function used. Performance of other models was also measured, blue: accounting for sequence similarity with IEDB epitopes, brown: including vaccination effect as the initial stimulation event, pink: excluding the effect of patient-specific amplitudes, green: excluding the effect of cross-reactivity between peptides from 1 st and 2 nd stimulation events. (E) Deconvolution of IFN-γ production by T cells in response to individual mutations within the peptide pools tested in C (WT→WT vs. Mut→Mut). Statistical significance ( p < 0.05) was evaluated by Wilcoxon matched-pairs test. All cytokine+ cell frequencies were demonstrated after background subtraction. See also ; and .

Article Snippet: SARS-CoV-2 Spike RBD (E484K, K417T, N501Y) , Sino Biological , Cat# 40592-V49H4-B-20.

Techniques: Control, Luminex, Binding Assay, Recombinant, Mutagenesis, Construct, Fluorescence, Enzyme-linked Immunospot, Variant Assay, Staining, Flow Cytometry, Sequencing

Journal: The Journal of Biological Chemistry

Article Title: The LDL receptor-related protein 1 (LRP1) facilitates ACE2-mediated endocytosis of SARS-CoV2 spike protein-containing pseudovirions

doi: 10.1016/j.jbc.2025.110227

Figure Lengend Snippet: LRP1 expression enhances ACE2-mediated internalization of SARS CoV-2 pseudovirions. HEK293 cells stably expressing ACE2 were transfected with GFP-LRP1, and transfection was confirmed by immunoblot analysis ( A ). B – D , LRP1-transfected cells were incubated with pseudovirions containing Vesicular Stomatitis Virus (VSV) ( B ), SARS-CoV-2 S-protein ( C ) or Δenv pseudovirions ( D ). (Students t test; ∗ p < 0.05, ∗∗∗∗ p < 0.0001).

Article Snippet: The SARS-CoV-2 spike protein receptor binding domain (his tagged, containing residues Arg319-Phe541) was purchased from R&D systems (Catalog number 10523-CV-100).

Techniques: Expressing, Stable Transfection, Transfection, Western Blot, Incubation, Virus