Blockade and reversal of PE adherence to CD36. Petri dishes coated with CD36 were preincubated with recombinant protein before testing for binding of PE. (A) rC1-2 but not other recombinant proteins, at 100 μg/mL, specifically blocked adherence to CD36 of PE from four phenotypically different P falciparum strains and clones. Strain MC R⁺ (▪); clone ItG2-ICAM (▨); clone ItG2-G1 (); clone Palo Alto (K⁻C⁺) (□). None of the other recombinant proteins affected PE adherence to CD36. Other recombinant proteins of MC PfEMP1 (Figs 1 and 2) did not block adherence of MC strain PE to CD36 (not shown). (B) Concentration-dependent blockade of PE adherence (strain MC) to CD36 with rC1-2 and rC1-2 [1-179]. IC₅₀ values were 1.2 μmol/L for rC1-2 and 0.78 μmol/L for rC1-2 [1-179]. (C) Concentration dependent reversal of MC PE adherence to CD36 with rC1-2. Adherent PE were incubated with GST or rC1-2 [1-233] and remaining adherent cells counted. The IC₅₀ value was 0.5 μmol/L.