fcγriia  (Bio X Cell)

Journal: bioRxiv

Article Title: FcγRI is the key determinant of antibody-mediated Zika virus infection of human placental macrophages

doi: 10.1101/2025.10.23.684201

Figure Lengend Snippet: FcγRI is the primary Fc receptor for antibody-mediated ZIKV infection in U937 cells (A) Representative histogram showing the surface expression of FcγRI, FcγRIIA, FcγRIIB and FcγRIIIA on U937 cells as detected by flow cytometry. FMO, fluorescence minus one. (B) U937 cells were infected with ZIKV (MOI 0.5) and in the presence of 33.3A06 IgG1 WT and Fc variants at a range of mAb concentrations. Infected cells were detected by 4G2 staining at 24 hr post infection (hpi) and flow cytometry. Antibody dilutions were performed in singlicate. The ADE assay was repeated in three independent experiments. (C) Data from the same experiment as in (B), but plotted as area under the curve (AUC) to obtain better quantitative analysis. The data shown are the results of three independent experiments. Data was analyzed using 1-way ANOVA and Tukey’s multiple comparison test: ***p < 0.001, ****p < 0.0001. (D, F, H) Fold changes in FcγRs binding affinity of the 33.3A06 Fc variants. K D values of the WT IgG1 and Fc variants binding to recombinant human FcγRI, FcγRIIA and FcγRIIB were determined by BLI. Relative binding affinity=K D (WT)/K D (variant). Variants with negative values show decreased binding affinity. NB, no detectable binding. (E, G, I) Correlations between peak ZIKV ADE and FcγRI, FcγRIIA and FcγRIIB relative binding affinity of the 33.3A06 IgG1 WT and Fc variants. Correlations were analyzed by Spearman’s Rho on log-transformed data. P-value was considered significant if <0.05. See also Figure S3, S4 and S5.

Article Snippet: FcγRIIA (IV.3; Stem cell technologies),FcγRIIB (2B6; Creative Biolabs) and FcγRIIIA (3G8; Biolegend).

Techniques: Infection, Expressing, Flow Cytometry, Fluorescence, Staining, Comparison, Binding Assay, Recombinant, Variant Assay, Transformation Assay

Journal: bioRxiv

Article Title: FcγRI is the key determinant of antibody-mediated Zika virus infection of human placental macrophages

doi: 10.1101/2025.10.23.684201

Figure Lengend Snippet: FcγRI-mediated enhanced ZIKV infection in U937 cells through both pre- and post-entry mechanisms. (A) Representative histogram showing the surface expression of FcγRI, FcγRIIA and FcγRIIB in WT, FCGR1A knockout, FCGR2A knockout and FCGR2B knockout U937 cell lines, respectively, as detected by flow cytometry. (B) WT, FCGR1A knockout, FCGR2A knockout and FCGR2B knockout U937 cell lines were infected with ZIKV (MOI 0.5) in the presence of 33.3A06 IgG1 mAb. Infected cells were detected by 4G2 staining and flow cytometry at 24 hpi. Data shown are representative of three independently performed experiments. (C) Data from the same experiment as in (B), but plotted as AUC to obtain better quantitative analysis. The data shown are the results of three independent experiments. Data was analyzed using 1-way ANOVA and Tukey’s multiple comparison test: ****p < 0.0001. (D) Representative histogram showing surface expression of FcγRI on WT and FcγRI overexpressed U937 cell lines as detected by flow cytometry. (E) WT and FcγRI overexpressed U937 cell lines were infected with ZIKV (MOI 0.5) in the presence of 33.3A06 IgG1 mAb at a range of mAb concentrations. Infected cells were detected by 4G2 staining and flow cytometry at 24 hpi. Data shown are representative of three independently performed experiments. (F) Data from the same experiment as in (E), but plotted as AUC to obtain better quantitative analysis. The data shown are the results of three independent experiments. Data were analyzed by Student’s t-test: ****p < 0.0001. (G) U937 cells were infected with ZIKV (MOI 1) alone or in the presence of 33.3A06 IgG1 mAb at 16ng/ml. ZIKV RNA from internalized virus was measured by qRT-PCR. (H) ZIKV RNA at 12hpi and 24hpi was measured by qRT-PCR. Data are representative of three independently performed experiments. Data were analyzed by Student’s t-test: *p<0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. Data are presented as mean values ± SD. IA OE, FcγRI overexpression; WT, wild type; IA KO, FCGR1A knockout; IIA KO, FCGR2A knockout; IIB KO, FCGR2B knockout.

Article Snippet: FcγRIIA (IV.3; Stem cell technologies),FcγRIIB (2B6; Creative Biolabs) and FcγRIIIA (3G8; Biolegend).

Techniques: Infection, Expressing, Knock-Out, Flow Cytometry, Staining, Comparison, Virus, Quantitative RT-PCR, Over Expression

Journal: bioRxiv

Article Title: FcγRI is the key determinant of antibody-mediated Zika virus infection of human placental macrophages

doi: 10.1101/2025.10.23.684201

Figure Lengend Snippet: FcγRI is a main receptor for ZIKV ADE in Hofbauer cells. (A) Representative histogram showing the surface expression of FcγRI, FcγRIIA, FcγRIIB and FcγRIIIA on Hofbauer cells as detected by flow cytometry. FMO, fluorescence minus one. (B) Hofbauer cells were infected with ZIKV (MOI 0, 0.25 or 5) alone or MOI 0.25 in the presence of mAbs at 16ng/ml. Infected cells were detected by 4G2 staining and flow cytometry at 24 hpi (biological replicates ± SD). Representative experiment from n = 2 donors. (C) Hofbauer cells were infected with ZIKV (MOI 0, 0.25 or 5) alone or MOI 0.25 in the presence of mAbs at 16ng/ml. ZIKV RNA was measured by qRT-PCR at 24 hpi (biological replicates ± SD). Representative experiment from n = 2 donors. Data was analyzed using 1-way ANOVA and Tukey’s multiple comparison test: *p<0.05, **p < 0.01, ****p < 0.0001. (D, E, F) Correlations between ZIKV infection in Hofbauer cells and FcγRI, FcγRIIA and FcγRIIB relative binding affinity of the 33.3A06 IgG1 and Fc variants. Correlations were analyzed by Spearman’s Rho on log-transformed data. P-value was considered significant if <0.05. See also Figure S4 and S5.

Article Snippet: FcγRIIA (IV.3; Stem cell technologies),FcγRIIB (2B6; Creative Biolabs) and FcγRIIIA (3G8; Biolegend).

Techniques: Expressing, Flow Cytometry, Fluorescence, Infection, Staining, Quantitative RT-PCR, Comparison, Binding Assay, Transformation Assay

Journal: Frontiers in Immunology

Article Title: Sub-neutralizing levels of antibodies against RSV F protein enhance RSV infection via Fc-FcγR interactions

doi: 10.3389/fimmu.2025.1594937

Figure Lengend Snippet: ADE requires the co-engagement of FcγRI and TLR4. (A) The percentage of RFP+ THP-1 cells at 12 h post-infection was detected by flow cytometry after blocking FcγRI, FcγRIIa and TLR4. (B) The expression of FcγRI, FcγRIIa and FcγRIIb in THP-1 cells at 24 h post-infection using qPCR. ** for p ≤ 0.01; ^^^ for p ≤ 0.001; ****, ^^^^ for p ≤ 0.0001. ns means no statistical significance compared to the T0 group.

Article Snippet: THP-1 cells were pre-incubated for 1 h with 20 μg/mL neutralization antibodies against TLR4 (clone HTA125) (Invitrogen,14-9917-82), or blocking antibodies (10 μg/mL) against FcγRI (10.1, BD), or FcγRIIa (BioXcell, BE0224-1MG).

Techniques: Infection, Flow Cytometry, Blocking Assay, Expressing