title: Synthetic peptides from two Pf sporozoite invasion-associated proteins specifically interact with HeLa and HepG2 cells.
abstract: Two recently described molecules have been associated with sporozoite traversal ability and hepatocyte entry: sporozoite invasion-associated proteins (SIAP)-1 and -2. The HeLa and HepG2 cell binding ability of synthetic peptides spanning the whole SIAP-1 and -2 sequences has been studied in the search for identifying these proteins' functionally active specific regions. Twelve HepG-2 and seventeen HeLa cell high-activity binding peptides (HABPs) have been identified in SIAP-1, 8 of them having high specific binding affinity for both cell lines. Four HepG2 HABPs and two HeLa HABPs have been identified in SIAP-2, one of them interacting with both HeLa and HepG2 cells. SIAP-1 and SIAP-2 HABPs bound specifically and saturably to heparin sulfate and chondroitin sulfate-type membrane receptors on host cells. Circular dichroism assays have shown high α-helix content in SIAP-1 and SIAP-2 HABP secondary structure. Immunofluorescence analysis has revealed that specific peptides against SIAP proteins are highly immunogenic in mice and that anti-SIAP-1 and -2 antibodies recognize the native protein in Plasmodium falciparum sporozoites. Polymorphism studies have shown that a most SIAP-1 and -2 HABPs are conserved among P. falciparum strains. Our results have suggested that SIAP-1 and -2 participate in host-pathogen interactions during cell-traversal and hepatocyte invasion and highlighted the relevance of the ongoing identification and study of potentially new molecules when designing a fully protective antimalarial vaccine.
authors.affiliation: Fundación Instituto de Inmunología de Colombia, Carrera 50 # 26-20, Bogotá, Colombia.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Arévalo-Pinzón
authors.forename: Hernando
authors.initials: H
authors.lastname: Curtidor
authors.forename: Marina
authors.initials: M
authors.lastname: Muñoz
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Patarroyo
authors.forename: Manuel E
authors.initials: ME
authors.lastname: Patarroyo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D060326:Chemistry Techniques, Synthetic; D002809:Chondroitin Sulfates / Q000378:metabolism; D002942:Circular Dichroism; D019084:Fluorescent Antibody Technique, Indirect; D006367:HeLa Cells; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000276:immunology / Q000378:metabolism / Q000469:parasitology; D054884:Host-Pathogen Interactions; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology / Q000494:pharmacology*; D010963:Plasmodium falciparum / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity; D011110:Polymorphism, Genetic; D011485:Protein Binding; D015800:Protozoan Proteins / Q000138:chemical synthesis / Q000276:immunology / Q000494:pharmacology*; D034101:Sporozoites / Q000737:chemistry* / Q000166:cytology / Q000276:immunology
chemical_list: D010455:Peptides; D015800:Protozoan Proteins; D002809:Chondroitin Sulfates