Cloning and Expression of Recombinant Camelid Single-Domain Antibody in Tobacco

Antibodies provide a suitable tool in fundamental research and their high affinity and specificity make them invaluable for diagnostic and therapeutic applications. A promising alternative to conventional antibodies are the heavy chain antibodies (VHH) of Camelidae having short length, high solubility and stability are preferred to other antibody derivatives. In this study, our goal was production of recombinant VHH antibody fragments (against cancer associated mucin, MUC1) in tobacco plants. The VHH gene cDNA was cloned in TA vector and then subcloned into a plant expression binary vector pBI 121. The VHH gene was inserted into the plant genome by agrobacterium-mediated transformation. The presence of VHH gene in transformed plants was confirmed by PCR.  Western blot analysis showed that the recombinant VHH protein was expressed in tobacco plant. ELISA results with MUC1 antigen confirmed that the biological activity and antigen-specific responses of the plant derived VHH protein compare favorably with that of the parent recombinant antibodies. This is the first report of production of camelied VHH antibody against tumor specific antigen from two-humped camel (Camelus bactrianus) in plants.