title: Immunogens containing sequences from antigen Pf332 induce Plasmodium falciparum-reactive antibodies which inhibit parasite growth but not cytoadherence.
abstract: Immunogens based upon sequences from the P. falciparum asexual blood stage antigen Pf332 were assessed for their capacity to induce antibodies inhibiting parasite growth or cytoadherence of infected erythrocytes in vitro. Selection of the Pf332 sequences was based on their reactivity with the human monoclonal antibody (MoAb) 33G2 which inhibits parasite growth as well as cytoadherence in vitro. Octameric multiple antigen peptides (MAP) were assembled based upon either a trimer of the minimal epitope recognized by the MoAb, VTEEI, or a Pf332 sequence including that motif, SVTEEIAEEDK. A dimer of SVTEEIAEEDK was also expressed in Escherichia coli, genetically fused to ZZ, two IgG-binding domains of staphylococcal protein A. Rabbit antibodies elicited by the immunogens reacted with Pf332 in immunofluorescence and in ELISA with Pf332 peptides which were also recognized by MoAb 33G2. The MAP with branched (VTEEI)3 peptide induced the highest titres of P. falciparum-reactive antibodies. In contrast to MoAB 33G2, none of the polyclonal Pf332 reactive sera cross-reacted with repeat sequences of the malaria antigen Pf155/RESA. The polyclonal Pf332-reactive antibodies inhibited parasite growth efficiently but had no or very low inhibitory effect in a cytoadherence assay. Thus, while Pf332 may be an important target for parasite neutralizing antibodies its involvement in cytoadherence is unclear.
authors.affiliation: Department of Immunology, Stockholm University, Sweden.
authors.forename: N
authors.initials: N
authors.lastname: Ahlborg
authors.forename: J
authors.initials: J
authors.lastname: Iqbal
authors.forename: M
authors.initials: M
authors.lastname: Hansson
authors.forename: M
authors.initials: M
authors.lastname: Uhlén
authors.forename: D
authors.initials: D
authors.lastname: Mattei
authors.forename: P
authors.initials: P
authors.lastname: Perlmann
authors.forename: S
authors.initials: S
authors.lastname: Stahl
authors.forename: K
authors.initials: K
authors.lastname: Berzins
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000913:Antibodies, Protozoan / Q000276:immunology* / Q000302:isolation & purification; D000953:Antigens, Protozoan / Q000737:chemistry / Q000276:immunology*; D001483:Base Sequence; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000276:immunology; D017931:DNA Primers / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D004912:Erythrocytes / Q000469:parasitology; D005455:Fluorescent Antibody Technique; D006801:Humans; D007117:Immunization, Secondary; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology; D010963:Plasmodium falciparum / Q000254:growth & development / Q000276:immunology*; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015815:Cell Adhesion Molecules; D017931:DNA Primers; D000939:Epitopes; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins