A person’s immune system can form antibodies against sugar molecules on the malaria pathogen, which protect against serious illness. A new blood test developed by a team of ETH Zurich and Swiss Tropical Institute researchers, headed by ETH Zurich Professor Peter Seeberger, enables these antibodies to be detected. The research results are published online in the journal “Nature Chemical Biology”.

Professor Peter Seeberger has been working on a sugar-based malaria vaccine for years. This new test takes him one important step closer to his goal. The malaria pathogen, plasmodium falciparum, carries poisonous sugar molecules – called GPIs for short – on its surface that are able to be individually identified. Professor Seeberger’s research team is developing a new method that demonstrates that the malaria pathogen’s toxic sugar molecules trigger a specific immune reaction in adults.

Antibodies in blood from malaria regions

Tests show that blood samples taken from adults living in areas of Africa where malaria is endemic contain specific antibodies against particular GPIs. While infection is still possible despite the antibodies, the consequences are less serious. The immune system recognizes the poisonous sugar molecules as foreign bodies and blocks their toxic impact. Not living in high-risk malarial areas, Europeans lack the relevant antibodies. Consequently, as soon as Europeans are infected with malaria, the number of antibodies increases significantly. Hence, there is a direct link between the amount of antibodies and protection against the disease.

Inexpensive detection

This new insight is thanks to a novel method for detecting antibodies. Faustin Kamena, a post-doc in Professor Seeberger’s lab, has developed a special chip that can, inexpensively and with minute quantities of blood serum and sugar molecules, determine whether or not someone has formed particular antibodies against various GPIs. In testing, the researchers use the purest possible GPIs, which can be produced synthetically mass-produced in a laboratory, as the Seeberger team has demonstrated in earlier research.

The new testing involves affixing over 64 pads comprising pinpoint dots to glass slides. Every little pad consists of several tiny heaps of different GPIs in varying concentrations. When blood serum is then administered to such a pad, possible antibodies specifically bind to certain sugar molecules. Dyes then reveal to which GPIs the antibodies have attached themselves.

Help for infants

Thanks to the information obtained from the chip, scientists can now produce the specific sugar molecules that the immune system has to recognize. The findings on natural resistance subsequently acquired are crucial to developing a sugar-based malaria vaccine, what could prove to be particularly beneficial to children in malaria-infested regions.

The millions of malaria sufferers are primarily infants under the age of five. Only adults develop antibodies against the malaria pathogen’s sugars. An infant’s immune system is incapable of recognizing and combating the toxic sugar molecules. The need for a new, selective vaccine is clear. Professor Seeberger states: “This evidence is another important step towards finding a malaria vaccine because we now know which antibodies protect adults.”

Original paper

Kamena, F. et al. (2008): Synthetic GPI array to study antitoxic malaria response, Nature Chemical Biology, online publiziert am 2. März 2008; doi:10.1038/nchembio.75