Recovery and isolation of recombinant human monoclonal antibody from transgenic tobacco plants

Early steps in the purification process for obtaining recombinant antibody from transgenic plants can significantly affect the overall purity and recovery. We investigate the effects of salt concentration, tissue grinding time and lowering pH on recovery and purification of a recombinant human monoclonal antibody (anti-Pseudomonas aeruginosa serotype O6ad) from transgenic tobacco plants. The presence of 450mM sodium chloride in the extraction buffer resulted in an 8-fold increase in antibody recovery when compared to using a sodium chloride-free buffer. The grinding time and the pH at which the extract was maintained were also found to have significant effects on antibody recovery. Generally, monoclonal antibody recovery could be enhanced by minimizing its interactions with native tobacco proteins and other components of the tobacco tissue. The overall yield of monoclonal antibody after optimization of the grinding and extraction steps was 30.3mg/kg of tobacco tissue, this being 12.5 times higher than that at a non-optimized extraction condition.