Prospects for new Malaria vaccine

Malaria is one of the most deadly pandemics to threaten human health. It consumes tens of thousands of lives each year in sub-Saharan Africa, most of who are young children. For example, each year close to 400 million people are infected with the disease, of which a million succumb to it. Hence all efforts must be channeled to find a robust vaccine for preventing it. Hence, research in this area is going at an intense pace in recent years. But unfortunately, there are no foolproof vaccines that have been formulated yet. A vaccine by name RTS S/AS01, which was put to trial during 2009, is specifically addressed to vulnerable children in the Third World. One of the reasons why formulating vaccines have proved challenging is due to the constantly adapting nature of malaria parasites. The latter either evolve drug-resistance or the mosquitoes themselves constantly change and become insecticide resistant. It is in this context that the thrust of new research should be based.

The article by Anthony Watts, posted in his website ‘Watts Up With That?’ presents recent discoveries in this area. The article is a summary of the research paper presented in the journal Proceedings of the National Academy of Sciences USA in September of 2010. Usually, malaria parasites use certain pathways to infect human cells. The identification of one such key pathway is believed to provide scientists will crucial leads. The research team at Walter and Eliza Hall Institute has been credited with this identification. They now believe that a new vaccine target can be produced, through which contact with malaria could be avoided.

The most lethal form of malaria is caused by the parasite Plasmodium Falciparum. The ability of this parasite to invade red blood cells through numerous channels is what makes it difficult to contain. It is conventional knowledge that the parasites enter red blood cells by using proteins called glycophorins. What the researchers found is another way through which the parasite enters red blood cells. This pathway

“does not involve glycophorins, instead requiring the binding of a parasite molecule named PfRh4 to Complement Receptor 1 (CR1), a common protein found on the surface of red blood cells. PfRh family of surface proteins is involved in the recognition of red blood cell receptors, which allows the parasite to attach to the red blood cell surface and gain entry.” (wattsupwiththat.com, 2010)

Professor Alan Cowman, who leads the research project at Walter & Eliza Hall Medical Research Institute, offers more insights into the identified mechanism. For example, he thinks that the malaria parasite uses this protein as a guide. The protein helps the parasite identify red blood cells upon which it can attach itself. Cowman reckons that the PfRh4-CR1 pathway is key for successful entry of malaria parasites into RBC. By virtue of this discovery, biologists can now device the ideal combination of proteins to serve as a vaccine. It is believed that by blocking both glycophorin and CR1 pathways, the chances of malaria infection is nearly eliminated. These results indicate “that if a vaccine were to stimulate the immune system to recognize and generate antibodies to the prevalent invasion pathways, there is a good chance it would lead to a significant decrease in malaria infection.” (wattsupwiththat.com, 2010) This area of research is still in its infancy and pending robust clinical longitudinal trials.

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