European Journal of Biomedical and Pharmaceutical Sciences

PRODUCTION OF BIOLOGICALLY ACTIVE HUMAN SECRETORY LEUKOCYTE PROTEASE INHIBITOR IN PLANTS: A PROTEIN WITH ANTI-VIRAL INCLUDING ANTI-HIV, ANTI-BACTERIAL, ANTI-INFLAMMATORY AND WOUND HEALING PROPERTIES

Sang-Hyuck Park, Elahe Crockett, Chuangsheng Mei, Thang Nguyen, Hussien F. Alameldin, Mariam Sticklen

ABSTRACT

The human Secretory Leukocyte Protease Inhibitor (SLPI) is widely viewed as an anti-HIV vaccine or treatment potential due to its broad spectrum of antimicrobial activities. However, human SLPI has not been pre-clinically tested yet for its’ therapeutic treatments because of its high production costs ($245/100ug; R & D System Corp), when produced in Escherichia coli. To overcome this limitation, we employed a plant production system for SLPI. We developed a series of plant expression vectors containing the human SLPI gene sequences driven by a green tissue specific (rubisco) promoter to produce this protein only in plant green tissues. We also used signal peptides to secure its’ accumulation in different sub-cellular compartments away from the cytoplasm, where normally most biological activities take place. Our results demonstrated that the recombinant human SLPI (rhSLPI) gene was successfully integrated into the plant genome, and transcribed and translated, and accumulated in plant apoplast (plant cell wall areas). Biological activity tests indicated that the plant produced-rhSLPI had inhibitory activities against serine protease α-chymotrypsin, suggesting that the end terminal partial cleavage may not have affected the rhSLPI catalytic activities. Our research demonstrates the feasibility of producing rhSLPI in plant system instead of its production in E. coli. The successful production of biologically active rhSLPI in plants might be a step forward to facilitating the potential use of rhSLPI in preclinical testing.

Keywords: Nicotiana tabacum, Tobacco, Secretory Leukocyte Protease Inhibitor (SLPI), Plant Expression Vector, AIDS/HIV, Biological Activity