Protective Antibodies Could be Key for Malaria Vaccine

Human antibodies that could be key to creating a highly effective malaria vaccination have been identified by an international research group led by researchers at Oxford.

“Following an infectious mosquito bite, the malaria parasite goes first to the human liver and then moves into the blood. Here it replicates ten-fold every 48 hours inside red blood cells – it is this blood-stage of the infection that leads to illness and can be fatal,” explains study author Simon Draper, Professor of Vaccinology and Translational Medicine at the Nuffield Department of Medicine, University of Oxford. “The malaria parasite has a protein called RH5, which must bind to a human protein on red blood cells called basigin in order to infect them. In this study, we were able to demonstrate which human antibodies effectively block RH5 from binding with basigin, thus preventing the parasite from spreading through the blood.”The study was part of a clinical trial in Oxford of the first vaccine that targets the RH5 malaria protein. “When someone is vaccinated, they make many different types of antibodies against the same RH5 target,” explains co-author and researcher Dr Daniel Alanine. “This study is key to understanding which specific antibodies are actually effective against malaria and which are not.”

A new antibody, which works by slowing down the speed in which RH5 binds to red blood cells was also discovered during the study. “This gives the antibodies that do block RH5 more time to act, helping them become more effective,” added study co-author Matthew Higgins, Professor of Molecular Parasitology at the Department of Biochemistry, University of Oxford.”

The current vaccine based on RH5 has so far shown real promise and continues to be trialled in the UK and Africa.

Collaborative research partners were the Burnet Institute (Australia), Center for Global Infectious Disease Research at the Seattle Children’s Research Institute (USA), Laboratory of Malaria and Vector Research (USA), Cell Surface Signalling Laboratory at the Wellcome Trust Sanger Institute (Cambridge), and ExpreS2ion Biotechnologies (Denmark).

*Published in the journal Cell.