Scientists discover malaria’s secret weapon

QIMR Berghofer Medical Research Institute scientists have worked out how the malaria parasite hijacks the body’s early immune response in severe malaria cases.

Dr Ashraful Haque, head of the Institute’s Malaria Immunology Laboratory, said the team had identified that the malaria parasite triggers a distracting signal that paralyses the body’s dendritic cells, which would normally instruct our body to fight off infectious agents.

“For the first time we can identify the nuts and bolts of exactly how our body allows the parasite to establish itself,” Dr Haque said.

“It’s because the parasite itself hijacks our immune system for its own ends, and prevents it from functioning properly.

“This finding opens new doors for research, so it’s now a question of determining whether we can improve a person’s immunity by blocking this signal to dendritic cells.”

Malaria was responsible for 600,000 deaths in Pacific, Asian and African nations in 2012. Australia reports up to 600 cases each year.

There is currently no vaccine against malaria. Current global initiatives to prevent the disease, such as providing insecticide-treated bed nets, are expensive and difficult to maintain. There is also evidence that drugs aimed at killing either malaria-bearing mosquitoes or the parasite itself are starting to fail.

Today’s findings were based on mouse models of severe cases of malaria. Researchers will now see if the same process occurs in milder cases, and whether these paralysing signals also operate in malaria-infected humans.

“We know we can switch off this signalling process in mouse models, and we’d hope this work encourages the development of signal blocking drugs, which could be incorporated in any potential vaccine or used as an immune-therapy in their own right.”

This research also involved three other research groups at QIMR Berghofer, headed by Professor Christian Engwerda, Dr Kelli MacDonald and Professor Geoff Hill. It was funded by the National Health and Medical Research Council (NHMRC).

The paper was published today in The Journal of Clinical Investigation and can be viewed at http://www.jci.org/articles/view/70698