Fig. 3. Determination of the relative levels of surface PfEMP1 by flow cytometry. (A) Graph showing the proportion of type 41 PfEMP1-expressing IEs labelled with mAbBC6 as a function of the concentration of mAbBC6. MAbBC6 labelling of K⁺ clones (solid symbols) is indistinguishable from that of K^– clones (open symbols). All analyses are representative of three independent experiments (mean±s.d.). (B) Graph showing the relative level of the mean fluorescence intensity (relative MFI; compared to the K⁺ clone 2B2) of type 41 PfEMP1-expressing IEs as a function of the concentration of mAbBC6. The key describes the symbols used, the var variant transcribed and the knobby phenotype for each clone in panels A and B. (C) Graph showing the proportion of IEs expressing var 6 PfEMP1 labelled with IgG from pooled adult hyperimmune serum (Adult IgG) as a function of the concentration of IgG. (D) Graph showing the relative MFI (compared to 2H3) of adult IgG-labelled IEs as a function of the concentration of IgG. (E) Graph showing the proportion of IEs expressing var 41 PfEMP1 labelled with adult IgG as a function of the concentration of IgG. (F) Graph showing the relative MFI (compared to 2B2) of adult IgG-labelled IEs as a function of the concentration of IgG.