Repeated cleaning of protein A affinity column with sodium hydroxide.

Protein A attached to an affinity adsorbent was shown to be remarkably resistant to 0.5 M NaOH. Even repeated treatments gave only a small decrease in functional capacity and no adverse effect on leakage of the protein A into the eluate. This simple cleaning procedure should be useful in applications where antibodies need to be purified free from the risk of contamination with endotoxins or micro-organisms, e.g., for in vivo therapy, either in clinical trials or experimental animals. It can also prevent cross-contamination when the same protein A adsorbent is used for different batches of antibody.