Perez H D, Hooper C, Volanakis J, Ueda A
J Immunol. 1987 Jul 15;139(2):484-9.
Serum and plasma from patients with active systemic lupus erythematosus contain a specific inhibitor of complement (C5)-derived chemotactic activity. We found that the inhibitor is antigenically related to the Bb fragment of complement factor B. Lupus plasma and purified inhibitor significantly reduced the chemotactic activity of zymosan-treated normal serum, an effect that was abolished by antibodies to factor B. Similar results were obtained when purified Bb was used. Neither purified inhibitor nor Bb inhibited the chemotactic activity of purified human C5a or C5a des Arg. As reported previously, the chemotactic activity of C5a des Arg was enhanced significantly by the addition of an anionic polypeptide (cochemotaxin) present in normal serum and plasma. Interestingly, both purified lupus inhibitor and Bb inhibited the chemotactic activity exhibited by mixtures of C5a des Arg and its cochemotaxin. This effect was due, most likely, to their ability to neutralize the enhancing effect of the cochemotaxin on the chemotactic activity of C5a des Arg. Immunoelectrophoresis and western blots revealed that the purified inhibitor reacted with anti-factor B and exhibited a similar charge and molecular weight as purified Bb.
活动性系统性红斑狼疮患者的血清和血浆中含有一种补体（C5）衍生趋化活性的特异性抑制剂。我们发现该抑制剂与补体因子B的Bb片段存在抗原相关性。狼疮血浆和纯化的抑制剂显著降低了经酵母聚糖处理的正常血清的趋化活性，抗因子B抗体可消除这一效应。使用纯化的Bb时也得到了类似结果。纯化的抑制剂和Bb均未抑制纯化的人C5a或C5a去精氨酸的趋化活性。如先前报道，正常血清和血浆中存在的一种阴离子多肽（共趋化因子）可显著增强C5a去精氨酸的趋化活性。有趣的是，纯化的狼疮抑制剂和Bb均抑制了C5a去精氨酸与其共趋化因子混合物所表现出的趋化活性。这种效应很可能是由于它们能够中和共趋化因子对C5a去精氨酸趋化活性的增强作用。免疫电泳和western印迹显示，纯化的抑制剂与抗因子B发生反应，且所带电荷和分子量与纯化的Bb相似。
