Boosting immune system to fight malaria

The team found how natural killer cells detect the infected red blood cells, and that natural killer cells with higher levels of the "pathogen recognition receptor" MDA5 respond better to a malaria infection. PHOTO: NTU

Scientists have discovered a potential treatment that could be effective in fighting severe malaria and other infectious diseases, by harnessing the body's own immune system.

The team from the Massachusetts Institute of Technology, Singapore-MIT Alliance for Research and Technology (Smart) and Nanyang Technological University (NTU) discovered a new molecular pathway - a series of interactions among molecules in a cell; and various compounds that could boost human immune cells' ability to identify and attack red blood cells infected by malaria.

This could improve a patient's chances of recovery and lower his risk of developing a more serious infection, said Smart and NTU in a statement.

Malaria, a disease caused by a mosquito-borne parasite, is a major problem in developing countries. According to the World Health Organisation, there were an estimated 216 million cases of malaria in 91 countries in 2016, with 445,000 deaths.

Some people are more vulnerable to malaria than others. The latest discovery, which was published in the journal PLOS Pathogens, sheds light on why.

During the initial phase of an infection by the malaria parasite, the first-line-of-defence cells known as natural killer (NK) cells destroy the infected red blood cells - if they detect them. Because of genetic differences, some people have more responsive NK cells, said the statement.

The team found how NK cells detect the infected red blood cells, and that NK cells with higher levels of the "pathogen recognition receptor" MDA5 respond better to a malaria infection. The scientists were also able to improve non-responding NK cells by activating MDA5 artificially with a synthetic drug compound in lab tests.

Dr Ye Weijian, the lead author of the study, said understanding the pathway that primes the NK cells to attack is important for developing novel strategies in boosting people's own immune system to fight malaria.

"Our discovery underpins future studies in immunotherapy and may hold the key to addressing multi-drug-resistant diseases," said Dr Ye, who is an NTU graduate under the Smart Graduate Fellowship.

Said Professor Peter Preiser, chair of NTU's School of Biological Sciences and a senior scientist in the research team: "Moving forward, the possibility of applying the same concept to other infectious diseases is boundless. We know that MDA5 is a sensor for infected red blood cells, so we can use synthetic drugs to improve MDA5 and improve NK cell function against other infectious diseases such as dengue, TB (tuberculosis) or even cancer."

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A version of this article appeared in the print edition of The Straits Times on October 11, 2018, with the headline Boosting immune system to fight malaria. Subscribe