An antibody that inhibits the binding of diphtheria toxin to cells revealed the association of a 27-kDa membrane protein with the diphtheria toxin receptor.
An antibody that inhibits the binding of diphtheria toxin to cells revealed the association of a 27-kDa membrane protein with the diphtheria toxin receptor.
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一种抑制白喉毒素与细胞结合的抗体揭示了 27 kDa 膜蛋白与白喉毒素受体的关联。
DOI：
10.1016/s0021-9258(18)54947-4
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
E. Mekada
中科院分区：
文献类型：
--
作者：
Ryo Iwamoto;Hiroyuki SenohS;Yoshio OkadaS;Tsuyoshi UchidaS;E. Mekada
用Vero细胞膜免疫小鼠，分离出一种阻断白喉毒素与Vero细胞结合的单克隆抗体。该抗体抑制白喉毒素和白喉毒素突变体CRM197与Vero细胞的结合，从而抑制白喉毒素的细胞毒性。该抗体不直接与白喉毒素受体分子（DTR14.5）发生反应。免疫沉淀和免疫印迹研究表明，该抗体与一种新的27 kDa膜蛋白（DRAP27）结合。当白喉毒素受体通过由该抗体制成的亲和柱时，受体仅在DRAP27存在的情况下被捕获。这些结果表明DRAP27和DTR14.5在Vero细胞膜上紧密结合，白喉毒素与受体结合的抑制是由于抗体与DRAP27分子的结合。利用125i标记抗体进行的结合研究表明，DRAP27在细胞表面的分子比白喉毒素结合位点要多得多。然而，细胞系对白喉毒素的敏感性与细胞表面DRAP27分子的数量存在相关性，提示DRAP27参与白喉毒素进入靶细胞的过程。
A monoclonal antibody that blocks the binding of diphtheria toxin to Vero cells was isolated by immunizing mice with Vero cell membrane. The antibody inhibits the binding of diphtheria toxin and also CRM197, a mutant form of diphtheria toxin, to Vero cells, and consequently inhibits the cytotoxicity of diphtheria toxin. This antibody does not directly react with the receptor molecule of diphtheria toxin (DTR14.5). Immunoprecipitation and immunoblotting studies revealed that this antibody binds to a novel membrane protein of 27 kDa (DRAP27). When diphtheria toxin receptor was passed through an affinity column made with this antibody, the receptor was trapped only in the presence of DRAP27. These results indicate that DRAP27 and DTR14.5 closely associate in Vero cell membrane and that the inhibition of the binding of diphtheria toxin to the receptor is due to the binding of the antibody to the DRAP27 molecule. Binding studies using 125I-labeled antibody showed that there are many more molecules of DRAP27 on the cell surface than diphtheria toxin-binding sites. However, there is a correlation between the sensitivity of a cell line to diphtheria toxin and the number of DRAP27 molecules on the cell surface, suggesting that DRAP27 is involved in the entry of diphtheria toxin into the target cell.