Long-term preservation of a whole parasite malaria vaccine for storage and delivery in the tropics

Over 1 million people die from malaria each year, mostly young African children. There is an urgent need for a vaccine. A vaccine called PlasProtect was developed that shows great promise in laboratory experiments in mice, and is scheduled for Phase I clinical trials later this year. The approach to this vaccine is to attenuate the parasites encapsulated within red blood cells; the parasites are unable to grow but can stimulate the host immune response. This is a similar approach to attenuated viruses that are used to vaccinate children against other pathogens. However, there is an important challenge in preserving the vaccine for delivery in places like Africa. The efficacy of the vaccine depends on preserving the red blood cell membrane, which requires cryopreservation of the vaccine in liquid nitrogen. This is not feasible in most malaria-endemic regions where there is limited health system capacity and poor access to freezers and electricity. To address this, a way was developed to desiccate the vaccine such that the red cells are preserved upon rehydration. It was shown that after rehydrating the desiccated vaccine, the parasites within the red cells are intact, express antigens on the red cell membrane, and stimulate a strong immune response in mice. This proposal will optimize the desiccation process, characterize the properties of the red cells and the parasites, and test the efficacy of the desiccated vaccine under various storage conditions.

Vaccines

Apr 2015 — Mar 2016

$125,204

Canada