An experimental vaccine against malaria induces an immune response in people over the course of 1 year similar to that mustered over a lifetime by people living in malarial zones, a study in the November PLoS Medicine shows.
People exposed to malaria churn out countless antibodies against the disease-causing parasite, but these immune system proteins fail to induce instant immunity, says physician Pierre Druilhe of the Pasteur Institute in Paris. Protection is built up through a combination of immune processes only gradually with constant exposure to the parasite, he says.
Some antibodies play key roles in fostering this natural immunity. One in particular responds to a protein on the parasite's surface by activating white blood cells called monocytes. Lab tests of monocytes taken from infected people have shown that, once activated, these cells can kill the parasite.