Expression of truncated KAHRP. (A) Schematic representation of truncated proteins (K119, etc) expressed in the transfected lines indicating the number of amino acids of each protein. Red boxes represent the signal peptide, yellow boxes the His-rich repeats, blue boxes the 5′, and green boxes the 3′ repeat regions (not drawn to scale). (B) Western blot analysis of all mutant cell lines compared to 3D7 parasite line detected with anti-K1A antisera. (C) Immunofluorescence assay of K119 compared to K(re) probed with 2 antibodies against different regions of KAHRP. The anti-K1A antibody recognizes the His-rich repeat region, whereas the anti-KAHRP (repeats) antibody was raised against the 5′ and 3′ repeat regions. The first panel of each row shows a phase-contrast image of an infected erythrocyte, the second panel shows nuclear DNA of the parasite stained with DAPI, the third panel shows the reaction with the KAHRP-specific antibody, and the fourth panel represents an overlay of the 3 previous panels. The anti-K1A antibody shows no cross-reaction with uninfected erythrocytes as shown by lack of reactivity in contrast to strong rim fluorescence observed in all P falciparum-infected red blood cells.