A receptor for antibody on B lymphocytes. II. Immunochemical and electron microscopy characteristics.
A receptor for antibody on B lymphocytes. II. Immunochemical and electron microscopy characteristics.
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DOI：
10.1084/jem.135.3.627
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发表时间：
1972-03-01
期刊：
影响因子：
--
通讯作者：
Mandel T
中科院分区：
文献类型：
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作者：
Basten A;Warner NL;Mandel T
抗体与B淋巴细胞表面的结合涉及免疫球蛋白分子的Fc片段。如直接结合和抑制研究所揭示的，所有免疫球蛋白类别并不平等地共享该特性。发现总IgG球蛋白比IgM更重地标记细胞，并且含有IgG1的组分比缺乏IgG1的IgG2组分更重。检测了各种纯化的骨髓瘤蛋白抑制抗体附着于B细胞的能力。用过量的IgG 2a、伊加或轻链蛋白预处理B细胞未能抑制，而相同浓度的IgG 1蛋白和较小程度的Ig2 B和IgM蛋白则抑制。在较低的蛋白浓度下，单独的IgG1骨髓瘤蛋白保留了抑制结合的能力。得出的结论是，B细胞上的抗体受体对IgG 1类具有明显的偏好性。虽然IgM和IgG2b抗体可以结合，但它们的亲合力较低，如果IgG1抗体过量，则可能不显著。没有发现任何证据表明补体参与了结合过程。例如，高稀释度的热灭活血清保留了标记B细胞的能力，而使用纯化的低分子量抗互补因子，一种有效的C '3抑制剂，不干扰抗体和细胞表面之间键的形成。抗小鼠免疫球蛋白F（ab）2片段不能阻止抗体接近B细胞，这意味着抗体结合受体和抗原结合（免疫球蛋白）受体是B细胞膜上的离散实体。尽管如此，在电子显微镜下观察到它们的表面分布之间的显着相似性。抗体结合受体被证明是成熟B细胞的标志物。它似乎不存在于造血前体干细胞上，并且在分化为抗体形成细胞的过程中丢失。
Binding of antibody to the surface of B lymphocytes was shown to involve the Fc piece of the immunoglobulin molecule. This property was not shared equally by all immunoglobulin classes as revealed by direct binding and inhibition studies. Total IgG globulin was found to label cells more heavily than IgM, and IgG1-containing fractions more heavily than IgG2 fractions lacking IgG1. The ability of various purified myeloma proteins to inhibit attachment of antibody to B cells was examined. Pretreatment of B cells with excess IgG2a, IgA, or light chain proteins failed to inhibit, whereas IgG1 proteins and to a lesser extent Ig2b and IgM proteins at the same concentrations did so. At lower protein concentrations, IgG1 myeloma protein alone retained the capacity to inhibit binding. The conclusion was reached that the receptor on B cells for antibody has a marked predilection for the IgG1 class. Although IgM and IgG2b antibody may bind, they do so with lower avidity and probably in insignificant amounts if IgG1 antibody is present in excess. No evidence was found to implicate complement in the binding process. For example, heat-inactivated sera at high dilution retained the ability to label B cells, while the use of purified low molecular weight anticomplementary factor, a potent inhibitor of C'3, did not interfere with the formation of the bond between antibody and cell surface. The failure of anti-mouse immunoglobulin F(ab)'2 fragments to prevent access of antibody to B cells implied that the antibody-binding receptor and antigen-binding (immunoglobulin) receptor are discrete entities on the B cell membrane. Despite this, a marked similarity between their surface distribution was observed on electron microscopy. The antibody-binding receptor was shown to be a marker for mature B cells. It did not appear to be present on hematopoietic precursor stem cells and was lost during differentiation to antibody-forming cells.