Washington, May 27: A one-two punch of malaria DNA virus and the virus used to vaccinate against smallpox spurs the human immune system to mount a powerful defense against malaria, researchers report. This approach might provide a basis for preventive and therapeutic vaccination in people, scientists said in a paper that appears in Monday’s online issue of the journal Nature Medicine.

The research team led by Adrian V S Hill of the Oxford University in England tested the combination on 63 volunteers and found the body’s response far surpassed either vaccine on its own.


The treatment did not induce complete immunity to malaria, but it provided partial protection. Researchers hope it will perform even better in field tests in Africa, where UN agencies say the mosquito-borne disease infects 300 million people a year and has become increasingly resistant to drugs.

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Smallpox vaccine virus used in the tests is a modified form that researchers said is safer than one that has caused problems in recent vaccination programs.


Using a strain of the smallpox vaccine known as MVA, the researchers found it had ‘‘a rare ability to selectively boost’’ T-cells — critical immune cells that attack invading disease — that have been primed in advance by the malaria protein, Hill said.


The DNA vaccine induces T-cells to respond to a malaria antigen called thrombospondin-related adhesion protein, or TRAP; the modified smallpox virus also produces a response to TRAP.

The T-cells react strongly to the malaria parasite, delaying its release from the liver into the bloodstream and reducing the number of released parasites. Bureau Report