Transgenic ginseng cell lines that produce high levels of a human lactoferrin

In order to produce a human lactoferrin (hLf) protein in cultured plant cells, we developed Korean ginseng (Panax ginseng) cell line using an oxidative stress-inducible peroxidase (SWPA2) promoter and characterized the production of human lactoferrin in cultured cells. A construct containing a targeting signal peptide from tobacco endoplasmic reticulum fused to human lactoferrin cDNA under the control of SWPA2 promoter was engineered. Transgenic Korean ginseng cell lines that produced a recombinant hLf protein were successfully generated and confirmed by PCR and Southern blot analyses. Western blot and ELISA analyses showed that hLf protein was synthesized in the transgenic cells. The production of hLf showed a maximal level (up to 3.0% of total soluble protein) in the stationary phase of callus cultures. These results suggest that the transgenic cell lines in this study will be biotechnologically useful for the commercial production of hLf protein in cell cultures, with no need for purification.