Plasmodium falciparum: Pfalhesin and CD36 Form an Adhesin/Receptor Pair That Is Responsible for the pH-Dependent Portion of Cytoadherence/Sequestration

The cytoadherent behavior of two Plasmodium falciparum (human malaria) cell lines, FCR-3 and IT04 (a cell line with elevated ICAM-1 adherence), was studied using CHO cells transfected with CD36 or ICAM-1 receptors as target cells. ICAM-1-mediated adherence was found to be relatively pH insensitive, whereas CD36-mediated adherence was pH sensitive and inhibited by monoclonal antibodies and peptides based on a region found in human band 3 protein and named pfalhesin. Immobilized pfalhesin was used as an affinity matrix to purify CD36 from extracts of C32 amelanotic melanoma cells, which have ICAM-1 as well as CD36 receptors, and bind both parasite cell lines. We conclude that pfalhesin and CD36-constitute an adhesin/receptor pair.