Malaria is the world's most frequent parasitic disease, affecting more than 100 countries in the tropical zones, mostly in Africa, and 40% of the world population, with more than a million deaths per year.
As a consequence countries affected by malaria also tend to be economically disadvantaged. The development of a vaccine constitutes a major scientific and health challenge. Research conducted at the Biochemistry Department of the University of Lausanne, Switzerland, has established a novel approach for the rapid discovery and development of vaccine candidates.
The malaria parasites injected through the bite of an infected female mosquito first develop in the liver and then in the blood. Clinical symptoms are associated with the latter stage and no vaccine is currently available. The development of an antibody-based vaccine to stop the proliferation of the parasite in the blood is thus clearly needed. The few candidates already tested or in the development process were identified over 20 years ago.
Taking advantage of the recently sequenced parasite genome, together with bioinformatics and peptide synthesis, Dr Giampietro Corradin's group, University of Lausanne, Switzerland, in close collaboration with Dr Andrey Kajava, University of Montpellier, France, has developed a novel approach for the rapid identification of malaria vaccine candidates. This approach is based on a bioinformatics selection of hundreds of short -helical coiled coil protein segments (30-40 amino acids long) which are able to maintain their conformation once they are chemically synthesized. In the first round of selection, all of 95 peptides synthesized were shown to be recognized by sera from malaria immune donors. Purified human antibodies specific to a dozen of these peptides could effectively inhibit parasite growth in vitro. Due to the rapidity of the identification and manufacturing process, time and cost to enter new vaccine candidates in clinical trials can be drastically reduced.