Journal: BMC Infectious Diseases

Article Title: Characterization of private mutations in the spike protein of SARS-CoV-2 correlates with viral prevalence

doi: 10.1186/s12879-025-11414-3

Figure Lengend Snippet: The L455F mutation increases the binding affinity of the spike protein to ACE2. A Fluorescence imaging of WT/EG.5.1/EG.5.1-L455F spike pseudovirus-infected 293/ACE2 cells at 72 h. B Relative Fluorescence Units (RFU) measured in 293/ACE2 cells infected with WT/EG.5.1/EG.5.1-L455F spike pseudoviruses at 72 h. *, P < 0.05, ****, P < 0.0001. C and D Biolayer interferometry was used to analyze the binding of biotinylated hACE2 to EG.5.1 spike protein or EG.5.1-L455F spike protein. The curves represent the results of a global fit of the data using a 1:1 binding model

Article Snippet: Recombinant Human ACE2 Protein (His & AVI Tag), Biotinylated (Sino Biological, Beijing, China), and SARS-CoV-2 EG.5.1 spike-L455F (synthesized by Sino Biological, Beijing, China) were tested for molecular interactions at concentrations of 500nM, 250nM, 125nM, 62.5nM and 31.25nM, respectively.

Techniques: Mutagenesis, Binding Assay, Fluorescence, Imaging, Infection

Journal: BMC Infectious Diseases

Article Title: Characterization of private mutations in the spike protein of SARS-CoV-2 correlates with viral prevalence

doi: 10.1186/s12879-025-11414-3

Figure Lengend Snippet: Complex models of the spike protein RBD with hACE2. A Structural representation of the complex between EG.5.1 RBD (yellow) and hACE2 (purple), highlighting the positions of L455 (red) and L456 (grey) in the EG.5.1 RBD. B Structural representation of the complex between EG.5.1-L455F RBD (green) and hACE2 (blue), highlighting the positions of F455 (red) and L456 (grey) in the EG.5.1-L455F RBD

Article Snippet: Recombinant Human ACE2 Protein (His & AVI Tag), Biotinylated (Sino Biological, Beijing, China), and SARS-CoV-2 EG.5.1 spike-L455F (synthesized by Sino Biological, Beijing, China) were tested for molecular interactions at concentrations of 500nM, 250nM, 125nM, 62.5nM and 31.25nM, respectively.

Techniques:

Journal: The FASEB Journal

Article Title: Autoantibodies targeting angiotensin‐converting enzyme 2 are prevalent and not induced by SARS ‐ CoV ‐2 infection

doi: 10.1096/fj.202402694R

Figure Lengend Snippet: Participant demographics and health characteristics.

Article Snippet: Briefly, recombinant ACE2 protein (generously provided by Dr. Yves Durocher, National Research Council of Canada (NRC), Montréal) was diluted in PBS (5 μg/mL working concentration) and was coated in a 384 well high‐binding polystyrene Nunc plate (Thermo Fisher Scientific, #460372) to a final amount of 50 ng of protein per well.

Techniques: Infection, Biomarker Discovery

Journal: The FASEB Journal

Article Title: Autoantibodies targeting angiotensin‐converting enzyme 2 are prevalent and not induced by SARS ‐ CoV ‐2 infection

doi: 10.1096/fj.202402694R

Figure Lengend Snippet: Overview of ACE2 serology results and establishment of seropositivity thresholds. (A) Overall view of anti‐ACE2 IgG, IgA, and IgM antibodies of the full cohort, including longitudinal sampling. (B) Quantitative Venn diagram representation of the distribution between IgM, IgA, and IgG ACE2 autoantibodies in the overall cohort of ACE2‐positive individuals. (C) IgG, IgA, and IgM anti‐ACE2 antibodies and associated threshold. IgG and IgA threshold was set at two cycles of 2 standard deviations (SD) from the mean of the presumed negative distribution. IgM threshold was set by a first cycle at 2SD and a second at 1SD from the mean of the presumed negative distribution.

Article Snippet: Briefly, recombinant ACE2 protein (generously provided by Dr. Yves Durocher, National Research Council of Canada (NRC), Montréal) was diluted in PBS (5 μg/mL working concentration) and was coated in a 384 well high‐binding polystyrene Nunc plate (Thermo Fisher Scientific, #460372) to a final amount of 50 ng of protein per well.

Techniques: Sampling

Journal: The FASEB Journal

Article Title: Autoantibodies targeting angiotensin‐converting enzyme 2 are prevalent and not induced by SARS ‐ CoV ‐2 infection

doi: 10.1096/fj.202402694R

Figure Lengend Snippet: Influence of clinical features and demographic characteristics on ACE2 autoantibodies prevalence. Odd ratios (OR) and 95% confidence interval (CI) were calculated for demographic characteristics and clinical features for individuals in relation to (A) IgG, (B) IgA and (C) IgM ACE2 autoantibodies. A table with a complete list of OR and 95% CI is available in the Table . The OR (CI95) are shown here on a log10 formatted axis.

Article Snippet: Briefly, recombinant ACE2 protein (generously provided by Dr. Yves Durocher, National Research Council of Canada (NRC), Montréal) was diluted in PBS (5 μg/mL working concentration) and was coated in a 384 well high‐binding polystyrene Nunc plate (Thermo Fisher Scientific, #460372) to a final amount of 50 ng of protein per well.

Techniques:

Journal: The FASEB Journal

Article Title: Autoantibodies targeting angiotensin‐converting enzyme 2 are prevalent and not induced by SARS ‐ CoV ‐2 infection

doi: 10.1096/fj.202402694R

Figure Lengend Snippet: Persistence of autoantibodies in serum over time and association with previous SARS‐CoV‐2 infection. (A) Some individuals had one or two follow‐up samples. ACE2 IgG, IgA, IgM is shown longitudinally (Follow up 1 ( n = 120), median time between draws (SD) = 35 days (10), Follow up 2 ( n = 35), median time between draws (SD) = 37 days (6)). (B) IgG, IgA, and IgM ACE2 autoantibodies levels are shown for individuals who never had SARS‐CoV‐2 and for individuals who had serological markers of SARS‐CoV‐2 infection and/or self‐reported a SARS‐CoV‐2 infection. Unpaired two‐sided Wilcoxon test was used to establish statistical significance ( n = 464), p ≤ 0.05 (*), p ≤ 0.01 (**), p ≤ 0.001 (***), p ≤ 0.0001 (****).

Article Snippet: Briefly, recombinant ACE2 protein (generously provided by Dr. Yves Durocher, National Research Council of Canada (NRC), Montréal) was diluted in PBS (5 μg/mL working concentration) and was coated in a 384 well high‐binding polystyrene Nunc plate (Thermo Fisher Scientific, #460372) to a final amount of 50 ng of protein per well.

Techniques: Infection

Journal: The FASEB Journal

Article Title: Autoantibodies targeting angiotensin‐converting enzyme 2 are prevalent and not induced by SARS ‐ CoV ‐2 infection

doi: 10.1096/fj.202402694R

Figure Lengend Snippet: Effect of ACE2 autoantibodies on ACE2 enzymatic activity and SARS‐CoV‐2 spike‐ACE2 binding. (A) ACE2 autoantibodies levels (IgG, IgA, IgM) in a subset of samples for which ACE2 enzymatic activity was assessed. (B) Levels of ACE2 enzymatic activity in individuals who had IgG and/or IgA and/or IgM ACE2 autoantibodies in contrast to the individuals who had no detectable ACE2 autoantibodies. (C) Levels of ACE2 enzymatic activity in individuals who self‐reported a SARS‐CoV‐2 infection and/or had serological markers of previous infection. (D) ACE2 autoantibodies levels in a subset of samples in which ACE2 and spike interaction was assessed. (E) Anti‐Spike IgG antibodies levels pre‐ and post‐depletion in sera. (F) % inhibition representing the ability of the sera to inhibit spike and ACE2 interaction pre‐ and post‐depletion. (G) % inhibition representing the ability of the sera to inhibit spike and ACE2 interaction in individuals who had IgG and/or IgA and/or IgM ACE2 autoantibodies above threshold in contrast to the individuals who had no detectable ACE2 autoantibodies. (H) Linear correlation between the ability of sera to inhibit Spike and ACE2 binding and the levels of Spike IgG antibodies in depleted sera. Unpaired two‐sided Wilcoxon test was used to establish statistical significance where applicable, p ≤ 0.05 (*), p ≤ 0.01 (**), p ≤ 0.001 (***), p ≤ 0.0001 (****).

Article Snippet: Briefly, recombinant ACE2 protein (generously provided by Dr. Yves Durocher, National Research Council of Canada (NRC), Montréal) was diluted in PBS (5 μg/mL working concentration) and was coated in a 384 well high‐binding polystyrene Nunc plate (Thermo Fisher Scientific, #460372) to a final amount of 50 ng of protein per well.

Techniques: Activity Assay, Binding Assay, Infection, Inhibition