There are several types of antibody purification. Which method to choose for purification depends on the purpose:
1. Crude purification: combine the serum or ascites used to prepare the antibody, and the cell supernatant. Directly use the salting out method to remove other impurities in these substances and obtain the protein components. However, because it is crude and pure, it will be mixed with a large amount of other proteins. The antibody obtained in this way has a low purity and is used for The background was relatively high in the experiment.
2. Universal purification: use antibody-binding protein Protein A, Protein G or Protein L. Because antibodies from different sources have different binding abilities to these antibody-binding proteins, it is necessary to choose which antibody will best bind to the protein based on the source of the antibody. For some single-chain antibodies, protein L is mostly used for purification. After affinity purification of the antibody-binding protein, only the antibody component is basically retained in the solution, and other proteins are removed, so the antibody purity can be relatively high. Relatively speaking, this method is the most commonly used purification method in large-scale antibody preparation, and many antibody companies use this method to purify antibodies.
3. Specific purification: However, some antibodies require particularly high purity and particularly good specificity, so the above two methods cannot be simply used for purification. A specific affinity purification column must be prepared by immobilizing the antigen and then purifying the antibody. What you get at this time are all antibodies against one antigen, which have the best specificity. Of course, since it involves operations such as antigen fixation, the cost is accordingly the highest.