Young W W, Tamura Y, Wolock D M, Fox J W
J Immunol. 1984 Dec;133(6):3163-6.
Two mouse IgG1 monoclonal antibodies specific for the Lewis(a) human blood group antigen were purified on protein A-Sepharose by using buffers of decreasing pH for elution. Unlike other IgG1 antibodies that eluted at pH 7.0 to 6.0, these antibodies could only be eluted at pH 4.0 to 3.0. The Fab and F(ab')2 fragments of these antibodies also eluted at pH 4.0 to 3.0, although the Fc fragment of one eluted at pH 6.0. This interaction of protein A with Fab was not due to anti-protein A antibody activity, because the presence of Lewis(a) trisaccharide did not prevent the binding of Fab to protein A-Sepharose and because Fab that had bound to solid phase hapten could still be recognized by protein A. Thus, certain mouse IgG1 antibodies possess determinants in their Fab portion recognized by protein A, allowing for the purification of such Fab fragments on protein A-Sepharose.
两种针对人Lewis(a)血型抗原的小鼠IgG1单克隆抗体，通过使用pH值逐渐降低的缓冲液进行洗脱，在蛋白A-琼脂糖凝胶上进行纯化。与其他在pH 7.0至6.0洗脱的IgG1抗体不同，这些抗体仅在pH 4.0至3.0时才能洗脱。这些抗体的Fab和F(ab')2片段也在pH 4.0至3.0时洗脱，尽管其中一种抗体的Fc片段在pH 6.0时洗脱。蛋白A与Fab的这种相互作用并非由于抗蛋白A抗体活性，因为Lewis(a)三糖的存在并不妨碍Fab与蛋白A-琼脂糖凝胶的结合，并且因为已结合固相半抗原的Fab仍可被蛋白A识别。因此，某些小鼠IgG1抗体在其Fab部分具有被蛋白A识别的决定簇，从而能够在蛋白A-琼脂糖凝胶上纯化此类Fab片段。
