Production of the Human Anti-Metastatic Melonoma Interleukin-2 in Maize Vegetative Biomass for Clinical Use

The E.coli produced recombinant human interleukin-2 (rhIL-2) has been approved by the Food and Drug Administration for the immunotherapeutic treatment of the end-stage metastatic melanoma and renal cell cancer. However, the E.coli produced rhIL-2 is very expensive (~$11,400 USD per treatment). In the present study, we explored the feasibility of producing rhIL-2 in transgenic Zea mays (maize) vegetative biomass instead of its production in E. coli because (1) maize vegetative biomass is abundant, (2) maize can cheaply produce recombinant proteins while obtaining its energy from freely available sun via photosynthesis, has an easy scale-up via reproduction system, can be easily grown by farmers in the field with minimum level of training, and has conserved protein folding machinery including glycosylation similar to that of human. The human hIL-2 gene was codon optimized to maximize its expression in plants. A plasmid construct containing the rhIL-2 regulated by a rubisco green-specific promoter, an endoplasmic reticulum-specific signal peptide, 6-histodin tag was developed and nos terminator The construct was transferred into the maize genome via the gene gun bombardment, and fertile plants developed. Molecular analysis confirmed that the human IL-2 had integrated, transcribed and translated in up to the 4th (T3) generation maize plants. When the same gene construct was transferred into the tobacco genome and the rhIL-2 was purified and its biological activity compared with the FDA approved commercially available E coliproduced version against the marine splenic CD4+ the mice cells, the plant-produced version was as effective as the commercially available E. coli-produced version. Research is needed to test the rhIL-2 producing maize in the field, and to perform preclinical and clinical trial for its potential commercial release. Production of the Human Anti-Metastatic Melonoma Interleukin-2 in Maize Vegetative Biomass for Clinical Use