Blocking capacity of 17C02-based molecules and FcγR utilization by THP-1-CD16A cells in the phagocytosis of IgG-opsonized human platelets. (A) Images of platelets sensitized with ITP serum and later incubated with THP-1-CD16A macrophages. Images were taken at the center of each well with Z-stacking. Phagocytosis was quantified using Imaris v9.6.0. The white arrows denote examples of phagocytosis of platelets; scale bar, 10 μm. (B) PI from 4 independent experiment are shown. Sensitization: “+” indicates platelets were incubated with normal human serum vs serum from patients with ITP. The PI was calculated as the number of platelets engulfed per 100 macrophages. The contribution of FcγRI, II, and III to phagocytosis was evaluated using Fc region deglycosylated blocking antibodies (final concentration of 10 μg/mL; 0.07 μM each): anti-FcγRI (clone 10.1), anti-FcγRIIA/B/C (clone AT10), or anti-FcγRIIIA (clone 3G8). The deglycosylated mouse IgG1 (clone MOPC-21), the deglycosylated mouse IgG2a (clone N/A-CP150), and human albumin were used as controls (final concentration of 0.07 μM). The blocking capacity of 17C02-based molecules was evaluated (17C02-albumin, 17C02-IgG1_OA, and deglycosylated 17C02-IgG2a) using the same comparative final molar concentration. Data are presented as the mean ± the standard deviation (n = 4-5). The statistical analysis was performed using Kruskal-Wallis and Dunn multiple comparison test (∗P < .05).