[Effects on Health] Malaria Vaccine Possible - Study

from All Africa

The Monitor (Kampala)

Peter Nyanzi
Kampala

A LANDMARK study by Karolinska Institutet in Sweden and Makerere University has indicated that it might soon be possible to develop a malaria vaccine.

The study titled, "Non-immune Immunoglobulin Binding and Multiple Adhesion Characterise Plasmodium Falciparum-Infected Erythrocytes of Placental Origin," unveiled important findings on how the malaria parasite conceals itself in the placenta.

Experts believe the findings can enable the development of an elusive vaccine and therapies to combat the disease, which is the top killer in many third world countries.

According to the study, the malarial parasite, Plasmodium Falciparium, hides in the placenta of pregnant women - the reason why pregnant women and babies are the main victims of the disease.

"For some reason, women in their first pregnancy lose the semi-immunity that is normally found in adults," said Niloofar Rasti, a KI graduate student who has been working on the study. "The placenta seems to be an anatomically favourable environment for a subpopulation of the parasites."

During one particular phase of its lifecycle, the parasite enters human red blood cells, where it produces proteins that attach themselves to receptors in the wall of the blood vessels. This causes the red blood cells to accumulate in organ capillaries, and gives rise to life-threatening symptoms.

Adults who have been infected several times can become partly immune as their defence system gradually starts to recognise the parasite's proteins. When the placenta is formed, however, a new environment is introduced with a different set of receptors.

This means that a new growth niche is made available to a subpopulation of the parasites. Earlier studies had suggested that each protein from the parasite attaches to only one specific protein, a receptor, in the placenta.

"Most of the parasites we studied could bind to three different receptors in the placenta," one of the researchers Niloofar Rasti said.

"This would mean that a future vaccine cannot be based on the principle of one protein-one receptor, as was previously believed."

The research group from Karolinska Institutet (KI), under the leadership of Prof. Mats Wahlgren, has been working with colleagues from KI's partner university in Uganda. The team included; Niloofar Rasti, Fatuma Namusoke, Arnaud Chêne, Qijun Chen, Trine Staalsoe, Mo-Quen Klinkert, Florence Mirembe, Fred Kironde, and Mats Wahlgren

The study is published by the American scientific journal PNAS.