Sedor J R, Carey S W, Emancipator S N
J Immunol. 1987 Jun 1;138(11):3751-7.
Contractile mesangial cells (MC) possess a number of macrophage-like characteristics, including oxygen radical generation. We suggest that under certain conditions MC may serve as immune effector cells in glomerulonephritis. Immune complex (IC) deposits are a hallmark of glomerulonephritis. Because IC elicit oxygen radicals from other cell types and because oxygen radicals can induce glomerular injury, we measured release of O2- by cultured rat MC in response to IC and, in separate experiments, the binding of IC to MC. Soluble and insoluble IC markedly stimulated dose- and time-dependent, saturable O2- release. Specific antibody (Ab) alone or mixtures of nonimmune Ab and antigen had no significant effect. IC-induced O2- release was not affected by cytochalasin B, an inhibitor of phagocytosis. Binding studies with radioiodinated IC demonstrated specific binding with an affinity of 1.56 X 10(6) M-1 and 1.02 X 10(5) receptors per cell. Both binding and O2- release required the Fc region of Ab. IC formed with F(ab')2 fragments did not bind specifically to or stimulate O2- release by MC. Cultured cells from rats depleted of bone marrow-derived phagocytes by irradiation produced amounts of O2- similar to cells from normal rats. These results provide evidence that IC affect the biology of the contractile glomerular MC in a manner that is dependent on the Fc region of Ab and suggest that MC structure and function may be altered at sites of injury.
收缩性系膜细胞（MC）具有许多巨噬细胞样特征，包括氧自由基的产生。我们认为，在某些情况下，MC可能在肾小球肾炎中充当免疫效应细胞。免疫复合物（IC）沉积是肾小球肾炎的一个标志。由于IC可从其他细胞类型中引发氧自由基，且氧自由基可诱导肾小球损伤，因此我们检测了培养的大鼠MC对IC的反应中O2-的释放，并在单独的实验中检测了IC与MC的结合。可溶性和不溶性IC均显著刺激剂量和时间依赖性、可饱和的O2-释放。单独的特异性抗体（Ab）或非免疫Ab与抗原的混合物没有显著影响。IC诱导的O2-释放不受吞噬作用抑制剂细胞松弛素B的影响。用放射性碘标记的IC进行的结合研究表明，其具有特异性结合，亲和力为1.56×10(6) M-1，每个细胞有1.02×10(5)个受体。结合和O2-释放均需要Ab的Fc区域。由F(ab')2片段形成的IC不会特异性结合或刺激MC释放O2-。通过照射使骨髓来源的吞噬细胞耗竭的大鼠的培养细胞产生的O2-量与正常大鼠的细胞相似。这些结果提供了证据，表明IC以依赖于Ab的Fc区域的方式影响收缩性肾小球MC的生物学特性，并提示MC的结构和功能可能在损伤部位发生改变。
