Circumsporozoite Protein (CSP) Conformational Changes During P. falciparum Sporogony

Elena Levashina of the Max Planck Institute for Infection Biology in Germany and Kelly Lee of the University of Washington in the U.S. will use cryoelectron tomography to image the three-dimensional ultrastructure of a protein on the surface of the malaria-causing parasite Plasmodium falciparum to help design better vaccines. Malaria kills half a million people annually, but there are still no highly effective vaccines available. One of the parasite's coat proteins, CSP, is a prime target for vaccine development. However, not much is known about its natural structure on the live parasite, which is how inhibitory antibodies produced in response to a vaccine will be able to recognize and destroy it. One of the best ways to observe the natural structure of a protein at high resolution is to immobilize it in non-crystalline ice and image it under very low (< −150 °C) temperatures. They will develop protocols to isolate large numbers of highly pure parasites directly from mosquitoes and carefully cryopreserve them on grids to maintain their natural form and enable clearer imaging. They will also use this high-resolution imaging technique to study how antibody binding affects the parasite. Their results will help design new vaccines that can produce highly active, inhibitory antibodies.