An edible vaccine for malaria using transgenic tomatoes of varying sizes, shapes and colors to carry different antigens.

Malaria, a disease caused by protozoan parasites of genus Plasmodium, is one of the world's biggest scourges. Over two billion individuals reside in the malaria endemic areas and the disease affects 300-500 million people annually. As a result of malarial-infection, an estimated three million lives are lost annually, among them over one million children (majority under 5 years of age). The mortality due to malaria has increased because of the spread of drug-resistant strains of the parasite, the breakdown of health services in many affected areas, the interaction of the disease with human immunodeficiency virus (HIV) infection, and possibly the effects of climate change. Infants and young children with malaria often die from severe anemia, cerebral involvement,or prostration caused by overwhelming infection; many new borns die from complications of low birth weight caused by maternal malaria during pregnancy. The scarce economic resources and lack of communication, infrastructure and adequate means of travel in the endemic areas make it extremely difficult to implement traditional infection control measures (i.e., mosquito control, preventive anti-malarial drugs and nets). To make the matter worse, both malarial parasites and its insect vectors are increasingly becoming resistant to anti-malarial agents (chloroquine) and insecticides (both DDT and melathione and related chemicals), respectively. By conventional wisdom, the immune mechanisms responsible for protection against malaria will require a multiple of 10-15 antigen targets for proper protection against various stages of malarial infection. By standard vaccination protocols, such a large number of targets would not be appropriate to be used for vaccination as a single dose due to antigenic competition. It would be almost impossible to immunize over two billion individuals who live in malaria susceptible areas with several carefully crafted immunization schedules delivered 4-6 weeks apart in the form of two different antigens as a single dose. Besides, if immunization schedules could be arranged, the stability of vaccines carrying different malarial antigens, their transport, and the logistics of vaccination would be an almost impossible task to achieve under the current fiscal constraints. We are proposing a unique way to circumvent these logistical difficulties to deliver the malaria vaccines to every susceptible home at a small fraction of a cost. We hypothesize that the anti-malaria edible vaccines in transgenic tomato plants where different transgenic plants expressing different antigenic type(s). Immunizing individuals against 2-3 antigens and against each stage of the life cycle of the multistage parasites would be an efficient, inexpensive and safe way of vaccination. Tomatoes with varying sizes, shapes and colors carrying different antigens would make the vaccines easily identifiable by lay individuals.