Malaria is a life-threatening parasitic disease transmitted by the bite of the female Anopheles mosquito, which transfers deadly one-celled parasites to human blood in an effort to nurture her eggs. The disease can be caused by one of four different parasites. The most lethal is Plasmodium falciparum, which is also responsible for the majority of infections.
Louis Schofield recently discovered that, as part of its life cycle inside its human host, the parasite releases an inflammatory toxin that appears to trigger the fever, convulsions and deaths associated with the disease.
Previous studies by Seeberger's colleagues demonstrated that small amounts of the toxin a tiny carbohydrate molecule called GPI could be used to effectively immunize mice against infection and reduce fatalities. But the human immune system does not recognize such small molecules as foreign and cannot make antibodies to destroy them.
Seeberger and Schofield designed a synthetic version of the toxin and attached it to a protein molecule in hopes that the newly created complex would be large enough for the body to recognize so that an immune response could be launched against it.
When a group of healthy, unvaccinated mice were injected with blood containing a deadly malarial parasite, all died. But when the synthetic toxin was injected into a group of healthy mice and they were subsequently injected with the parasite, 65 to 95 percent survived.
The immunized mice also had enhanced protection from severe inflammatory conditions associated with the disease, including swelling of the brain, the researchers found.
Seeberger and his colleagues are continuing to refine their vaccine formulations to achieve a 100 percent survival rate. They hope that similar results will be seen in people.
According to the World Health Organization (WHO), malaria is one of the major public health problems, along with HIV/AIDS and tu
'"/>
Contact: Beverly Hassell
b_hassell@acs.org
202-872-4065
American Chemical Society
14-Aug-2002