Institute of Immunology and Infection Research (IIIR),
School of Biological Sciences,
The University of Edinburgh,
Update November 2014: Herbert Opi’s paper exploring why children who co-inherit sickle cell trait and alpha-thalassaemia lose the protection against malaria accorded by each mutation individually, to be published in the inaugural edition of eBiomedicine http://www.ebiomedicine.com/article/S2352-3964%2814%2900008-5/abstract
Host-parasite interactions and life-threatening malaria.
Individual variation in disease symptoms is one of the unexplained features of malaria. Although approximately one million children die from malaria every year, many more suffer milder, non-life-threatening forms of the disease. Despite decades of research, it is unclear to what extent this individual variation in disease severity is due to parasite factors, host factors, or a combination of the two. Our main interest lies in investigating the malaria parasite properties (virulence factors) and human genetic factors (malaria susceptibility genes) that contribute to life-threatening malaria. The importance of this work is that by gaining a greater understanding of the processes leading to severe disease, it may be possible to develop drugs or vaccines to prevent children dying from malaria.
The main focus of the lab is investigating how Plasmodium falciparum infected red blood cells bind to human cells and cause disease. We are studying three major types of host-parasite interaction: rosetting of infected red cells with uninfected red cells; adhesion of infected red cells to Human Brain Endothelial Cells (HBEC-binding); and platelet-mediated clumping of infected red cells. Rosetting is a parasite adhesion phenotype strongly associated with life-threatening malaria in African children. We aim to understand the molecular mechanisms of rosette formation in order to develop rosette-inhibiting vaccines or drugs. In particular, we are studying the role of var genes encoding the infected erythrocyte variant surface protein PfEMP1 in rosetting, and the potential for a PfEMP1 vaccine to inhibit rosetting. Recently, we have also begun to focus on HBEC-binding as an in vitro model for cerebral malaria, investigating the role of PfEMP1 variants as parasite adhesion molecules responsible for HBEC-binding, and the potential for anti-PfEMP1 drugs and vaccines to treat or prevent cerebral malaria. On the host side, we continue to study a red blood cell protein called complement receptor one that plays a crucial role in rosette formation. We are also investigating the role of human IgM natural antibodies in malaria parasite adhesion.
In all our projects we aim to combine detailed in vitro investigation of laboratory parasite strains with studies on fresh clinical isolates, in order to establish the relevance of our findings to malaria infections in the real world.