Ghetie V, Vitetta E S
Cancer Immunobiology Center, Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-8576, USA.
Mol Biotechnol. 2001 Jul;18(3):251-68. doi: 10.1385/MB:18:3:251.
Immunotoxins are chimeric proteins consisting of an antibody linked to a toxin. The antibodies most frequently used for the preparation of immunotoxins are murine monoclonal antibodies belonging to IgG isotype. The most used toxins for the chemical construction of immunotoxins are Ricin toxin A chain in its deglycosylated form and recombinant Pseudomonas endotoxin with the cell-binding domain deleted. The linkage of the antibody to the toxin can be accomplished by chemical methods using reagents that crosslink antibody to toxin. The usual crosslinkers attach disulfide groups into the antibody molecule to form a disulfide bond between the antibody and the toxin. Disulfide bonds are susceptible to reduction in the cytoplasm of the targeted cells thereby releasing the toxin so that it can exert its cytotoxic activity only into the cells (e.g., tumor cells) binding the antibody moiety. This article describes various methods to obtain antibodies and toxins and several procedures for their crosslinking as well as "in vitro" and "in vivo" testing of the immunotoxins efficacy.
免疫毒素是由与毒素相连的抗体组成的嵌合蛋白。制备免疫毒素最常用的抗体是属于IgG同种型的鼠单克隆抗体。用于免疫毒素化学构建的最常用毒素是去糖基化形式的蓖麻毒素A链和缺失细胞结合域的重组假单胞菌内毒素。抗体与毒素的连接可以通过使用使抗体与毒素交联的试剂的化学方法来完成。常用的交联剂将二硫键连接到抗体分子中，以在抗体和毒素之间形成二硫键。二硫键在靶细胞的细胞质中易于还原，从而释放毒素，使其仅能对结合抗体部分的细胞（如肿瘤细胞）发挥细胞毒性活性。本文描述了获得抗体和毒素的各种方法、它们交联的几个步骤以及免疫毒素功效的“体外”和“体内”测试。
