Plant chloroplasts are capable of producing significant quantities of high quality bioengineered proteins with biomedical applications. Improving the output of therapeutic antibodies, vaccines and diagnostic antigens through use of our pliable expression platform will provide an important technological advance compared with the current mammalian and microbial cell culture platforms. Our innovative approach combines a next-generation plant platform, for rapid line production, with established downstream processing and a novel genetic technology that permits site-directed insertion of one or more transgenes in chloroplasts. This platform advance has the potential for significant production of antigens, such as for the hantavirus, in contained, biosecure facilities under conditions of Good Manufacturing Practice. We propose in this Phase I project to develop the technical feasibility for rapid production of hantaviral gene products using our technology for chloroplast transgenesis in our target platform. Production of hantavirual proteins using the enabling strategies in Phase I is key to our Phase II goal of applying the technology collaboratively to produce sufficient quality antigens for diagnostic and immunogenicity assays