Kimberly R P, Ahlstrom J W, Click M E, Edberg J C
Hospital for Special Surgery, Cornell University Medical College, New York, New York 10021.
J Exp Med. 1990 Apr 1;171(4):1239-55. doi: 10.1084/jem.171.4.1239.
To investigate the ability of FcgammaRIII(PMN), the GPI-anchored isoform of FcgammaRIII (CD16) in polymorphonuclear leukocytes (PMN), to mediate transmembrane signaling events, we measured changes in membrane potential with DiOC(5) and in intracellular calcium with indo-1. FcgammaR were ligated by anti-FcgammaRIII mAb 3G8 (IgG and Fab), anti-FcgammaRII mAb IV.3 (IgG and Fab), and human IgG aggregates. Cell bound mAbs were also crosslinked by goat F(ab')(2) anti-mouse IgG. 3G8 IgG elicited a rapid change in Ca(2+), which was unaffected by EGTA, Vibrio cholerae toxin (CT), or Bordetella pertussis toxin (PT), and was abolished by BAPTA . Univalent receptor binding with 3G8 Fab gave no response but crosslinking with F(aV)2 GAM gave a rapid Ca2, response. Neither IV.3 Fab, IV.3 IgG, nor crosslinking of IV.3 Fab elicited a calcium signal. PI-PLC-treated PMN with the density of FcgammaRIII(PMN) reduced to that of FcgammaRII showed an unattenuated change in Ca(2+), with a 3G8 stimulus. The effects of IgG aggregates paralleled those of 3G8 mAb. These data indicate that multivalent ligation of FcgammaRIII(PMN) initiates an increase in [Ca(2+)];, derived from intracellular stores, that is distinct from both the FMLP- and FcgammaRII-induced responses. Ligand-dependent interaction with FcgammaRII is not required. Since FcgammaRIII(PMN) can internalize the FcgammaRIII-specific probe Con A-opsonized E and lyse anti-FcgammaRIII heteroantibody-opsonized chick E, this GPI-anchored molecule mediates both signal transduction and integrated cell responses.
为了研究多形核白细胞（PMN）中FcγRIII（PMN）（FcγRIII的糖基磷脂酰肌醇锚定同种型，即CD16）介导跨膜信号转导事件的能力，我们用DiOC(5)测量膜电位变化，并用indo-1测量细胞内钙变化。FcγR由抗FcγRIII单克隆抗体3G8（IgG和Fab）、抗FcγRII单克隆抗体IV.3（IgG和Fab）以及人IgG聚集体连接。细胞结合的单克隆抗体也通过山羊F(ab')(2)抗小鼠IgG交联。3G8 IgG引起[Ca(2+)]i的快速变化，该变化不受EGTA、霍乱弧菌毒素（CT）或百日咳博德特氏菌毒素（PT）的影响，但被BAPTA消除。3G8 Fab的单价受体结合无反应，但与F(aV)2 GAM交联产生快速的[Ca2+]i反应。IV.3 Fab、IV.3 IgG或IV.3 Fab的交联均未引发钙信号。用磷脂酰肌醇特异性磷脂酶C（PI-PLC）处理使FcγRIII（PMN）密度降低至FcγRII密度的PMN，在3G8刺激下[Ca(2+)]i变化未减弱。IgG聚集体的作用与3G8单克隆抗体相似。这些数据表明，FcγRIII（PMN）的多价连接引发细胞内储存的[Ca(2+)]i增加，这与FMLP和FcγRII诱导的反应均不同。不需要与FcγRII进行配体依赖性相互作用。由于FcγRIII（PMN）可以内化FcγRIII特异性探针伴刀豆球蛋白A调理的E，并裂解抗FcγRIII异源抗体调理的鸡E，因此这种糖基磷脂酰肌醇锚定分子介导信号转导和整合的细胞反应。
