Chloroplast transformation in plants for the production of vaccines

Plants offer several advantages for the production of subunit vaccines, including ease of scalability, low production cost, reduced risk of contamination with animal or bacterial pathogens, relative ease of genetic manipulation, and complex protein modification machinery. In addition, when the production of these vaccines occurs through the genetic manipulation of the chloroplast, high levels of expression can be achieved and gene spread controlled, as transgenes are not transmitted through pollen. Our main focus, at the Laboratory of Molecular Biotechnology in UPIBI, is to examine the expression of several antigens with potential as vaccine components for various diseases, including HIV and diabetes, in plants like lettuce, tomato and alfalfa, through the genetic transformation of chloroplasts via particle bombardment. We have generated several vectors that are specific for the transformation of lettuce and alfalfa, encoding both diabetes (gad) and HIV (p24 and nef) antigens, and are currently working on the optimization of tissue culture regeneration methods for these crops. Our most important aims are to achieve high levels of expression, obtaining stable proteins, and to optimize the choice of plant species for production of, ideally, oral edible vaccines. Production at a large scale of these chloroplast-derived vaccines in the edible tissue of plants would combine production and delivery systems.