Fig. 3. MTIP is expressed in invasive Plasmodium zoite stages. (A) Western blot analysis of P. yoelii sporozoite extracts (spz) and of extracts from a schizont-enriched fraction of P. yoelii blood stages (bs). The anti-MTIP antiserum specifically recognized a protein doublet in both zoite preparations that closely migrated at approximately 25 kDa. (B) Indirect immunofluorescence assay (IFA) with anti-MTIP antiserum showed that MTIP is concentrated around the periphery of merozoites during the late stages of blood stage schizogony (Bar, 2 µm). (C) IFA with anti-MTIP showed strong peripheral fluorescence in P. yoelii sporozoites that were isolated from mosquito salivary glands (Bar, 2 µm).