Indirect immunofluorescence images of P. falciparum schizonts stained with rabbit IgG (green) induced by 10 viral-vectored vaccines expressing malaria antigens, and negative control vectors lacking a malaria antigen. Nuclei are counterstained with 4,6-diamidino-2-phenylindole (blue). All sera were tested against 3D7 strain parasites, with the exception of anti-PfRH1 for which FVO strain parasites were used. All images to same scale as Giemsa stained image (top left, on which scale bar indicates 5 μm).Douglas AD, Williams AR, Illingworth JJ, Kamuyu G, Biswas S, Goodman AL, Wyllie DH, Crosnier C, Miura K, Wright GJ, Long CA, Osier FH, Marsh K, Turner AV, Hill AV, Draper SJ. The blood-stage malaria antigen PfRH5 is susceptible to vaccine-inducible cross-strain neutralizing antibody. Nat Commun. 2011 2:601.

Localization of Pf38 fused to a GFP reporter and expressed in an inducible system that allows strong surface expression. MS, mid-schizont; LS, late schizont; M, merozoite. Pf38-GFP was mostly concentrated in secretory organelles at the apical end of the parasite, exclusively at an early stage of schizont development, suggesting that Pf38 probably predominantly resides in these apical organelles. Pf38 is a GPI-anchored protein.Sanders PR, Gilson PR, Cantin GT, Greenbaum DC, Nebl T, Carucci DJ, McConville MJ, Schofield L, Hodder AN, Yates JR 3rd, Crabb BS. Distinct protein classes including novel merozoite surface antigens in Raft-like membranes of Plasmodium falciparum. J Biol Chem. 2005 280:40169-76.

Expression and co-localization of proteins of Pfs38 complex on Plasmodium merozoites. Co-localization studies were performed by immunofluorescence assays. Merozoites were labelled with (a) mouse anti-Pfs38 and rabbit anti-GLURP or with (b) mouse anti-Pfs38 and rabbit anti-Pfs41 antibodies or with (c) mouse anti-Pfs38 and rabbit anti-Pfs12 antibodies or with (d) mouse anti-Pfs38 and rabbit anti-PfsMSP165 antibodies. Partial co-localization was observed between Pfs38 and other proteins of 6-Cys complex with co-localization coefficient of 0.75, 0.61, 0.82, and 0.83 for a–d, respectively. Td represent bright field images. Pfs38 partially co-localized with GLURP, Pfs41, Pfs12, and MSP-1, advocating the co-existence of proteins of 6-Cys protein complex on the merozoite surface (Fig. 3a–d). These results were corroborated by cosedimentation analysis of parasite-derived polypeptides. Western blotting and LC–MS/MS analysis of the glycerol gradient fractions revealed the presence of Pfs38, Pfs41, Pfs12, GLURP, MSP-1, and SERA5 in a single fraction, suggesting that these proteins exist in a complex on the parasite.Paul G, Deshmukh A, Kaur I, Rathore S, Dabral S, Panda A, Singh SK, Mohmmed A, Theisen M, Malhotra P. A novel Pfs38 protein complex on the surface of Plasmodium falciparum blood-stage merozoites. Malar J. 2017 16(1):79