Thrombospondin related adhesive protein (TRAP), a potential malaria vaccine candidate.

We have investigated whether naturally induced immunity to Plasmodium falciparum thrombospondin related adhesive protein contributes to protection against malaria in humans. We have carried out a case control study in children living in an endemic region of West Africa to reveal associations between PfTRAP seroprevalence and the risk of cerebral malaria. Sera collected from the case and control groups were analysed by ELISA to compare their serum reactivity against PfTRAP, the circumsporozoite protein and the merozoite surface protein 1. Children with uncomplicated malaria had a significantly higher PfTRAP seroprevalence when compared to children with cerebral malaria. The risk of developing cerebral malaria appeared to depend on the reciprocal relationship between sporozoite inoculation rates and humoral immunity against PfTRAP. Our results suggest that naturally induced humoral immunity against PfTRAP contributes to the development of protection against severe malaria. Experimentally induced immunity against TRAP in different rodent models has consistently proven to elicit a high degree of protection against malaria. This together with the functional properties of TRAP and data describing CD4 and CD8 epitopes for PfTRAP indicate that this molecule could increase the protective efficiency of available sporozoite malaria vaccines.