Detection of a LFA-1-like epitope on the surface of erythrocytes infected with a strain of Plasmodium falciparum.

The adhesion of erythrocytes infected with Plasmodium falciparum (P. falciparum) is one of the major pathological features of severe malaria. Several potential receptors to endothelium for falciparum-infected erythrocyte on endothelium have been described. Recently, the malaria binding site on ICAM-1(CD54) has been mapped to a site distinct but overlapping with the LFA-1 (CD11a/CD18) site. We detected by flow cytometry, confocal laser microscopy and immunoprecipitation, a molecule expressed at the surface of erythrocytes infected with mature stages of the M96 strain of P. falciparum that was recognized by a monoclonal antibody (mAb) (TS1/22) directed against an LFA-1 epitope. However, this molecule was not recognized by mAbs directed against other epitopes of LFA-1 or against other integrins. Furthermore, the mAb TS1/22 partially inhibited cytoadherence of parasitized red blood cells to human-brain microvascular endothelial cells. The expression of a molecule sharing an epitope with human LFA-1 integrin on the parasitized erythrocyte surface could be involved in the sequestration of these cells and thus in the pathogenesis of severe disease.