Programa de Doctorado en Ciencias Biomédicas, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico.
Cell Immunol. 2010;263(1):114-21. doi: 10.1016/j.cellimm.2010.03.006. Epub 2010 Mar 15.
In neutrophils, two receptors for IgG antibodies, namely FcgammaRIIA and FcgammaRIIIB are constitutively expressed, and a third one, FcgammaRI, can be upregulated by interferon-gamma. Whether FcgammaRIIIB is capable of triggering phagocytosis by itself is still controversial. The main role of FcgammaRI has not been clearly established in these cells. To address this problem, neutrophils were treated with interferon-gamma, and then phagocytosis mediated by each type of Fcgamma receptor was evaluated by flow cytometry. FcgammaRIIA was the most efficient receptor for phagocytosis. FcgammaRIIIB could mediate phagocytosis but much less efficiently than FcgammaRIIA. Both FcgammaRIIA- and FcgammaRIIIB-mediated phagocytosis were blocked by inhibitors of Src family kinases, Syk, PI 3-K, and ERK. In contrast, interferon-gamma-induced FcgammaRI was not able to mediate phagocytosis. Also, FcgammaRI did not activate ERK in the nucleus, but was however able to stimulate an efficient calcium rise. These data show that different neutrophil Fcgamma receptors possess different phagocytosis capabilities: FcgammaRIIA and FcgammaRIIIB, but not FcgammaRI, promote phagocytosis.
在中性粒细胞中，两种 IgG 抗体受体，即 FcγRIIA 和 FcγRIIIB 持续表达，而第三种受体 FcγRI 可以被干扰素-γ上调。FcγRIIIB 是否能够自行触发吞噬作用仍存在争议。在这些细胞中，FcγRI 的主要作用尚未明确。为了解决这个问题，用干扰素-γ处理中性粒细胞，然后通过流式细胞术评估每种 Fcγ 受体介导的吞噬作用。FcγRIIA 是吞噬作用最有效的受体。FcγRIIIB 可以介导吞噬作用，但效率远低于 FcγRIIA。FcγRIIA 和 FcγRIIIB 介导的吞噬作用都被Src 家族激酶抑制剂、Syk、PI3-K 和 ERK 阻断。相比之下，干扰素-γ诱导的 FcγRI 不能介导吞噬作用。此外，FcγRI 不能在细胞核中激活 ERK，但能够刺激有效的钙升高。这些数据表明，不同的中性粒细胞 Fcγ 受体具有不同的吞噬作用能力：FcγRIIA 和 FcγRIIIB，但不是 FcγRI，促进吞噬作用。
