localization of the selected ES antigens by immunoelectron microscopy. Ultrathin sections of P. falciparum-infected erythrocytes (at late trophozoite/schizont stages) were labeled with specific sera (against the four selected proteins) and gold-conjugated secondary antibody. Localization is depicted as black dots (of gold particles) for PfSEL1 (a, i and ii), PfSEL2 (b), PfEK (c), and PfEP (d). Enlarged panels and arrows show detailed images of the intracellular staining pattern. Scale bar, 250 nm. Immunoelectron microscopic studies were done to reconfirm their extracellular localization. Interestingly in the case of PfSEL1, a large number of gold particles could be seen on the surface of iRBCs and being secreted in the extracellular milieu, thus confirming the release of identified proteins beyond the iRBC plasma membrane. It would be interesting to study the trafficking of these proteins in the infected erythrocyte as they lack the host cell targeting/PEXEL motif shown to target proteins to the host erythrocyte. In addition to immunolocalization studies, we also observed that all four ESAs were strongly recognized by sera from P. falciparum-infected patients. Together these results provided strong support for the extracellular nature of the identified P. falciparum proteins.
Singh M, Mukherjee P, Narayanasamy K, Arora R, Sen SD, Gupta S, Natarajan K, Malhotra P. Proteome analysis of Plasmodium falciparum extracellular secretory antigens at asexual blood stages reveals a cohort of proteins with possible roles in immune modulation and signaling. Mol Cell Proteomics. 2009 8(9):2102-18
Other associated proteins
PFID | Formal Annotation |
---|---|
PF3D7_0931200 | selenoprotein |
PF3D7_1121300 | tyrosine kinase-like protein |
PF3D7_1229400 | macrophage migration inhibitory factor |
PF3D7_1403600 | selenoprotein |