Möller G, Coutinho A
J Exp Med. 1975 Mar 1;141(3):647-63. doi: 10.1084/jem.141.3.647.
Attempts were made to identify the non-Ig lymphocyte receptor responsible for B-cell induction by antigen and polyclonal B-cell activators (PBA). As a first step, the role of C'3 and Fc receptors was analyzed. It was shown that complement could be fixed onto B cells to such an extent that the lymphocytes could not bind complement-coated red cells, but this did not result in induction of polyclonal antibody synthesis, nor did it inhibit the lymphocytes response to PBA. However, the C'3 receptros possessed a passive focussing role in the induction of polyclonal antibody responses. Thus, PBA that had fixed complement activated polyclonal responses at lower concentrations than the same substances that had not fixed complement. Most likely the dual binding of PBA molecules to B cells by the PBA and the C'3 receptors caused more PBA molecules to be bound to each cell. However, the focussing function of the C'3 receptors was several orders of magnitude smaller than that of the Ig receptors. Analogous studies were carried out with Fc receptors. Binding of different types of antigen-antibody complexes did not cause activation of polyclonal or specific antibody synthesis, nor did it significantly interfere with induction of antibody synthesis by PBA substances.
研究人员试图鉴定负责由抗原和多克隆B细胞激活剂（PBA）诱导B细胞的非Ig淋巴细胞受体。第一步，分析了C'3和Fc受体的作用。结果表明，补体可固定在B细胞上，以至于淋巴细胞无法结合补体包被的红细胞，但这既未导致多克隆抗体合成的诱导，也未抑制淋巴细胞对PBA的反应。然而，C'3受体在多克隆抗体反应的诱导中具有被动聚焦作用。因此，已固定补体的PBA比未固定补体的相同物质在更低浓度下就能激活多克隆反应。很可能是PBA分子通过PBA和C'3受体与B细胞的双重结合导致每个细胞结合了更多的PBA分子。然而，C'3受体的聚焦功能比Ig受体的聚焦功能小几个数量级。对Fc受体进行了类似的研究。不同类型抗原 - 抗体复合物的结合既未导致多克隆或特异性抗体合成的激活，也未显著干扰PBA物质诱导的抗体合成。
