![The Fc region of anti-CD44 is critically required to inhibit macrophage FcγR-mediated phagocytosis. Macrophages were treated with unmodified (intact) anti-CD44 or with Fc-deactivated variants [deglycosylated and F(ab′)2]. Platelets opsonized with different anti-GPIIb/IIIa IgG subclasses were added to macrophages to induce phagocytosis. (A-D) Macrophages were treated with unmodified anti-CD44 or Fc-deactivated anti-CD44 variants before incubation with platelets opsonized with different IgG subclasses. Dotted lines indicate the level of phagocytosis by untreated macrophages (100%). Data are from 3 to 5 experiments (mean ± standard error of the mean). The percentage of phagocytosis was calculated as (PI treatment/PI untreated control) × 100%, where PI (phagocytic index) is the average number of phagocytosed platelets per 100 macrophages. ****P < .0001, ***P < .001, 1-way analysis of variance with Tukey’s post hoc test. Degly., deglycosylated; IgG1, rat IgG1 (MWReg30); IgG2a, mouse IgG2a (2G1 or 5C4); IgG2b, mouse IgG2b (10B5).](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/137/15/10.1182_blood.2020009497/1/bloodbld2020009497f4.png?Expires=1722719488&Signature=gesyigq5LLhwud-x7OuMgGhPhy9WxqMM9blbwCY-Vt5XdCUG0VlvlybH4-JEukQ6jJlJ5-kXuRxypgyiok2mAtlY3Fv1lYoMi2N88gIdPpeOHEEwPIqQTFtf-rS77BM0ulK~J0k-qppZvXnfwXoWaP1Pgp~F0BeKv1HNsBGgGtZzve7CnL8Bfh4eiGPTuGAN-vHOcmU1e3uvlK8GPrAVHgR0FvczqOauKTqkeOEOE8mR22Cqz36HqfqQf4CAXuV0VzwRarcksT8HONSzG1Ex~eOSU~95IWczNlRgPiewF9pLrHfNvn-mPJ6q7ZmJp4DBhynJPyP4arFJM8drN6wxOA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
The Fc region of anti-CD44 is critically required to inhibit macrophage FcγR-mediated phagocytosis. Macrophages were treated with unmodified (intact) anti-CD44 or with Fc-deactivated variants [deglycosylated and F(ab′)2]. Platelets opsonized with different anti-GPIIb/IIIa IgG subclasses were added to macrophages to induce phagocytosis. (A-D) Macrophages were treated with unmodified anti-CD44 or Fc-deactivated anti-CD44 variants before incubation with platelets opsonized with different IgG subclasses. Dotted lines indicate the level of phagocytosis by untreated macrophages (100%). Data are from 3 to 5 experiments (mean ± standard error of the mean). The percentage of phagocytosis was calculated as (PI treatment/PI untreated control) × 100%, where PI (phagocytic index) is the average number of phagocytosed platelets per 100 macrophages. ****P < .0001, ***P < .001, 1-way analysis of variance with Tukey’s post hoc test. Degly., deglycosylated; IgG1, rat IgG1 (MWReg30); IgG2a, mouse IgG2a (2G1 or 5C4); IgG2b, mouse IgG2b (10B5).