Formulation and pre-clinical evaluation of transmission blocking potential of plant-produced plasmodium falciparum sexual stage PFS25 and PFS230 vaccine candidates

Malaria is a serious and sometimes fatal mosquito-borne disease caused by a protozoan parasite. There are hundreds of millions of cases of malaria occurring each year around the world, and nearly one million people are killed. Malaria is transmitted by the female Anopheles mosquito which takes up the sexual stage of the parasite during a blood meal. The parasite completes the sexual stages in the mosquito before being transmitted to a subsequent host. Vaccines directed against the mosquito parasitic stages are designed to halt development into oocysts and thus are transmissionblocking vaccines. We are targeting different antigens for development of an effective transmission blocking vaccine and have successfully produced multiple versions of the Pfs25 and Pfs230 antigens in our plant-based launch-vector system and have shown them to generate strong transmission blocking activity. We are currently evaluating multiple versions of our antigens in dose ranging and adjuvant studies. Results of these studies will determine a candidate vaccine for clinical development.