Polyreactive antibodies bind to a variety of structurally unrelated antigens. The function of these antibodies, however, has remained an enigma, and because of their low binding affinity their biological relevance has been questioned. Using a panel of monoclonal polyreactive antibodies, we showed that these antibodies can bind to both Gram-negative and Gram-positive bacteria and acting through the classical complement pathway can inhibit bacterial growth by lysis, generate anaphylatoxin C5a, enhance phagocytosis, and neutralize the functional activity of endotoxin. Polyreactive antibody-enriched, but not polyreactive antibody-reduced, IgM prepared from normal human serum displays antibacterial activity similar to that of monoclonal polyreactive IgM. We conclude that polyreactive antibodies are a major contributor to the broad antibacterial activity of the natural antibody repertoire.

中文翻译：

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天然抗体库的广泛抗菌活性归因于多反应性抗体。

多反应性抗体与多种结构无关的抗原结合。然而，这些抗体的功能仍然是一个谜，并且由于它们的低结合亲和力，它们的生物学相关性受到质疑。使用一组单克隆多反应性抗体，我们发现这些抗体可以与革兰氏阴性菌和革兰氏阳性菌结合，并且通过经典补体途径起作用，可以通过裂解抑制细菌生长，产生过敏毒素 C5a，增强吞噬作用，并中和功能内毒素的活性。从正常人血清中制备的富含多反应性抗体而非减少多反应性抗体的 IgM 显示出与单克隆多反应性 IgM 相似的抗菌活性。