Canine Mast Cell Activation via Human IgG1 and IgG4
Canine Mast Cell Activation via Human IgG1 and IgG4
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DOI：
10.1159/000080659
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发表时间：
2004-09
影响因子：
2.8
通讯作者：
Yoshitaka Sato;R. Teshima;R. Nakamura;K. Takagi;Nobuo Sasaki;J. Sawada;S. Kitani
中科院分区：
文献类型：
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作者：
Yoshitaka Sato;R. Teshima;R. Nakamura;K. Takagi;Nobuo Sasaki;J. Sawada;S. Kitani
背景：我们已报道犬肥大细胞瘤来源的CM-MC细胞可被犬免疫球蛋白激活，并表达高亲和力免疫球蛋白受体(Cine FcγRI)。犬FcγRIα亚基的预测氨基酸序列与人类的同源性为72%。这些结果表明，犬FcγRI具有与人免疫球蛋白结合的活性，并使我们研究了狗FcγRI和人免疫球蛋白对CM-MC的激活作用。方法：用流式细胞术检测人免疫球蛋白与犬FcγRI的结合。[Ca~(2+)]i通过犬Fc-γRI增加或释放组胺，并用抗人Ig G聚集结合的Fc-γRi后测定4种人Ig G亚类。为了确定犬FcγRI与人Ig G1或Ig G3的结合活性，用未标记的人Ig G 1或Ig G3检测了~(125)I标记的犬Ig G从犬FcγR I上的置换情况。结果：与FITC-人免疫球蛋白孵育后，CM-MC细胞的荧光强度较对照细胞明显增强(约50倍)。犬Fcγ与人Ig G1或Ig G4结合后，观察到显著的钙反应和组胺释放。用未标记的人总免疫球蛋白或人免疫球蛋白G_1与犬FcγRI预先孵育，以剂量依赖方式取代~(125)I标记的犬免疫球蛋白，而与人免疫球蛋白G_3预先孵育不能检测到~(125)I标记的狗免疫球蛋白的置换。结论：犬FcγRI与人Ig G 1或Ig G4具有显著的结合活性，而Ig G 2或Ig G3与犬FcγR I在CM-MC细胞上无明显反应。
Background: We have reported that canine mastocytoma-derived CM-MC cells are activated via canine IgG and express a high-affinity IgG receptor (canine FcγRI). The predicted amino acid sequence of the canine FcγRI α subunit was found to be 72% similar to that of humans. These results suggest that canine FcγRI have binding activity with human IgG and led us to investigate CM-MC activation via canine FcγRI and human IgG. Methods: The binding of human IgG to canine FcγRI was examined by flow cytometry using FITC-conjugated human IgG. [Ca2+]i increase or histamine release via canine FcγRI and the four human IgG subclasses was measured following aggregation of IgG-bound FcγRIs by anti-human IgG. To determine the binding activity of canine FcγRI with human IgG1 or IgG3, the displacement of 125I-labeled canine IgG from canine FcγRI was examined by unlabeled human IgG1 or IgG3. Results: The fluorescence intensity of CM-MC cells was markedly (about 50 times) elevated by incubation with FITC-human IgG compared with the fluorescence of the control cells. A significant (p < 0.01) calcium response and histamine release were observed following aggregation of canine FcγRIs bound with human IgG1 or IgG4. 125I-labeled canine IgG was displaced from canine FcγRI by preincubation with unlabeled total human IgG or human IgG1 dose-dependently, whereas no displacement was detected by preincubation with human IgG3. Conclusions: Canine FcγRI possesses a significant binding activity with human IgG1 or IgG4, while IgG2 or IgG3 did not significantly react with canine FcγRI on CM-MC cells.