Fig. 1.

Two forms of PfRH2a are expressed in the schizont extracts of different parasite strains. (A) Schematic representation of P. falciparum RH family members, indicating the signal peptides (red), the RH homology region (blue), the unique region against which antibodies were raised (green), and the C-terminal transmembrane domain (brown). The lengths of the proteins are given in amino acids (aa). (B) Western blots of schizont extracts and supernatant proteins of 3D7, 3D7ΔRH2a, and W2mef parasites were probed with MAb C22. Similar results were obtained in 3 other independent experiments. (C and D) Western blots of 3D7 and 3D7ΔRH2a schizont extracts and supernatant proteins were probed with MAb C19 (C) and C15 (D). RH2a was detected at ∼360 and 270 kDa in schizonts, and an additional 140-kDa band was observed in culture supernatants.