acrobiosystems antibody  (ACROBiosystems)

Journal: Science Advances

Article Title: Increased SARS-CoV-2 IgG4 has variable consequences dependent upon Fc function, Fc receptor polymorphism, and viral variant

doi: 10.1126/sciadv.ads1482

Figure Lengend Snippet: Relative concentration of SARS-CoV-2 ancestral spike trimer-specific ( A ) IgG1, ( B ) IgG2, ( C ) IgG3, and ( D ) IgG4 in plasma collected 1 month (median = 28 days post-vaccination) post-dose two ( n = 46) and three ( n = 31) of BNT162b2 vaccine as measured by multiplex. Statistical significance was assessed using Mann-Whitney U test. ( E ) Two-tailed Spearman correlation between WT SARS-CoV-2 antigen-specific IgG1 to IgG4 and FcγR (FcγRIIa-H131, FcγRIIa-R131, FcγRIIIa-V158, and FcγRIII-F158) binding. * P < −0.05, ** P < 0.01, *** P < 0.001, and **** P < 0.0001. RBD, receptor binding domain.

Article Snippet: Standard curves were generated using IgG1 to IgG4 anti–SARS-CoV-2 RBD broadly neutralizing mAbs (AM395b, Acro Biosystems).

Techniques: Concentration Assay, Multiplex Assay, MANN-WHITNEY, Two Tailed Test, Binding Assay

Journal: Science Advances

Article Title: Increased SARS-CoV-2 IgG4 has variable consequences dependent upon Fc function, Fc receptor polymorphism, and viral variant

doi: 10.1126/sciadv.ads1482

Figure Lengend Snippet: ( A and B ) Change in binding of ancestral spike trimer-specific plasma antibodies to soluble FcγRIIIa-V158 and FcγRIIIa-F158 dimers following the addition of IgG4 mAb cocktails into post-dose two plasma. ( C ) Comparison of ancestral spike-specific IgG titers post-dose two BNT162b2 vaccination ( n = 24) and following addition of 0.05 nM (0.007 μg/ml) or 0.2 nM (0.029 μg/ml) of IgG4 SARS-CoV-2 mAbs. ( D to G ) Change in IgG1-IgG4 titers following IgG4 addition into plasma. Significant differences were assessed using Friedman’s test with Dunn’s multiple comparison. Error bars indicate interquartile range. Binding of ( H ) IgG1 and ( I ) IgG4 mAb cocktails to IgG1 or IgG4 detection reagents, FcγRIIIa-V158 and FcγRIIIa-F158 dimers. The normalized median fluorescent intensity (MFI) of each detection reagent was plotted. ( J ) Comparison of the ability of IgG1 and IgG4 mAb cocktails to induce ADCC. ( K ) FcγRIIIaV and FcγRIIIaF binding of IgG4 mAb cocktail into IgG1 mAb cocktail (2.5 nM/0.365 μg/ml). ( L ) ADCC mediated by IgG4 mAb cocktails titrated into IgG1 mAb cocktail (10 nM; 1.46 μg/ml). Error bars indicate SEM. Curves were fitted using a four-parameter nonlinear regression model. **** P < 0.0001.

Article Snippet: Standard curves were generated using IgG1 to IgG4 anti–SARS-CoV-2 RBD broadly neutralizing mAbs (AM395b, Acro Biosystems).

Techniques: Binding Assay, Comparison

Journal: Science Advances

Article Title: Increased SARS-CoV-2 IgG4 has variable consequences dependent upon Fc function, Fc receptor polymorphism, and viral variant

doi: 10.1126/sciadv.ads1482

Figure Lengend Snippet: ( A ) ADCP activity of plasma collected post-dose two of BNT162b2 vaccination ( n = 24) before and after addition of IgG4 SARS-CoV-2 mAb cocktail. ( B ) ADCP activity induced by IgG1 (pink) and IgG4 (blue) mAb cocktails. ( C ) ADCP of ancestral spike-coated beads mediated by IgG4 mAb cocktail titrated into IgG1 mAb cocktail at 1 nM (0.146 μg/ml; red) or 0.1 nM (0.015 μg/ml; blue). Change in total IgG and IgG subclass distribution of spike-bound antibodies in individuals with ( D to H ) low total IgG (below median IgG titer) and ( I to M ) high total IgG (above median IgG titer) post-dose two and following addition IgG4. ( N and O ) Log change in FcγRI, FcγRIIa-H131, and FcγRIIa-R131 binding following (N) 0.05 nM (0.007 μg/ml) and (O) 0.2 nM (0.029 μg/ml) IgG4 addition into post-dose two plasma. Significant differences were assessed using Friedman’s test with Dunn’s multiple comparison. Binding of ( P ) IgG1 and ( Q ) IgG4 mAb cocktails to IgG1 or IgG4 detection reagents and recombinant soluble FcγRI, FcγRIIa-H131, and FcγRIIa-R131. The normalized MFI of each detection reagent was plotted. ( R and S ) FcγRI and FcγRIIa binding of IgG4 mAb cocktail titrated into IgG1 mAb cocktail at (R) saturating (2.5 nM/0.365 μg/ml) or (S) half-maximal binding (EC 50 ; 0.3 nM/0.044 μg/ml) IgG1 concentration and binding to FcγRs were assessed. Curves were fitted using a four-parameter nonlinear regression model. ( T ) Model predictions for FcγRIIa-H131 and FcγRIIa-R131 immune complex formation were compared with multiplex experimental measurements. Landscape illustrating the relationship between IgG1 and IgG4 concentrations for predicting ( U ) FcγRIIa-H131 and ( V ) and FcγRIIa-R131 immune complex formation. Colour indicated the predicted change in complex formation from baseline (blue, decrease; red, increase). * P < 0.05, ** P < 0.01, *** P < 0.001, and **** P < 0.0001.

Article Snippet: Standard curves were generated using IgG1 to IgG4 anti–SARS-CoV-2 RBD broadly neutralizing mAbs (AM395b, Acro Biosystems).

Techniques: Activity Assay, Binding Assay, Comparison, Recombinant, Concentration Assay, Multiplex Assay

Journal: Science Advances

Article Title: Increased SARS-CoV-2 IgG4 has variable consequences dependent upon Fc function, Fc receptor polymorphism, and viral variant

doi: 10.1126/sciadv.ads1482

Figure Lengend Snippet: Comparison of ( A to D ) spike-bound IgG1 to IgG4 titers and ( E ) ADCP responses of plasma collected post dose three mRNA vaccination ( n = 13, median = 28 days post-vaccination) and IgG4 depleted plasma. ( F ) Log change in binding to soluble FcγRs of post-dose three plasma following IgG4 depletion. Statistical significance was assessed using Wilcoxon test. Log change in binding to FcγRIIa and FcγRIIIa of post-dose two mRNA vaccination plasma ( n = 24, median = 28 days post-vaccination) following ( G ) 0.05 nM (0.006 μg/ml) and ( H ) 0.2 nM (0.022 μg/ml) addition of (Fab) 2 fragments of IgG4 mAbs into. Significant differences were assessed using Friedman’s test with Dunn’s multiple comparison. * P < 0.05, ** P < 0.01, *** P < 0.001, and **** P < 0.0001.

Article Snippet: Standard curves were generated using IgG1 to IgG4 anti–SARS-CoV-2 RBD broadly neutralizing mAbs (AM395b, Acro Biosystems).

Techniques: Comparison, Binding Assay

Journal: Science Advances

Article Title: Increased SARS-CoV-2 IgG4 has variable consequences dependent upon Fc function, Fc receptor polymorphism, and viral variant

doi: 10.1126/sciadv.ads1482

Figure Lengend Snippet: ( A to D ) Comparison of [(A) to (D)] Delta and ( E to H ) BA.2 spike-bound IgG1 to IgG4 titers post-dose two BNT162b2 vaccination and following IgG4 addition. ( I to L ) Change in binding to soluble FcγRs of post-dose two Delta-specific or BA.2-specific antibodies following IgG4 mAb cocktail addition. Significant differences were assessed using Friedman’s test with Dunn’s multiple comparison. Error bars indicate interquartile range. Binding of ( M ) IgG1 and ( N ) IgG4 mAb cocktails to IgG1 or IgG4 detection reagents or recombinant soluble FcγRs against BA.2 Spike trimer. The normalized MFI of each detection reagent was plotted. ( O to P ) FcγR binding activity of IgG4 mAb cocktail was titrated into IgG1 mAb cocktail and binding to FcγRs against BA.2 Spike. Error bars indicate SEM. Curves were fitted using a four-parameter nonlinear regression. * P < 0.05, ** P < 0.01, *** P < 0.001, and **** P < 0.0001.

Article Snippet: Standard curves were generated using IgG1 to IgG4 anti–SARS-CoV-2 RBD broadly neutralizing mAbs (AM395b, Acro Biosystems).

Techniques: Comparison, Binding Assay, Recombinant, Activity Assay

Journal: Science Advances

Article Title: Increased SARS-CoV-2 IgG4 has variable consequences dependent upon Fc function, Fc receptor polymorphism, and viral variant

doi: 10.1126/sciadv.ads1482

Figure Lengend Snippet: ( A ) Summary of binding affinity of IgG4 to different FcγRs. ( B ) At high spike-specific IgG titers, elevated IgG4 competes with IgG1 and IgG3 for antigen binding, resulting in reduced FcγRIIa binding and ADCP. ( C ) At low anti-spike titers, increased IgG4 increases total antigen-bound IgG, leading to an overall increase in FcγRI and FcγRIIa binding and therefore ADCP. ( D ) Elevated IgG4 reduces FcγRIIIa engagement and ADCC because of the poor ability of IgG4 to bind FcγRIIIa.

Article Snippet: Standard curves were generated using IgG1 to IgG4 anti–SARS-CoV-2 RBD broadly neutralizing mAbs (AM395b, Acro Biosystems).

Techniques: Binding Assay