title: Use of long synthetic peptides to study the antigenicity and immunogenicity of the Plasmodium vivax circumsporozoite protein.
abstract: Three long synthetic peptides corresponding to amino (N), repeat (R) and carboxyl (C) regions of the Plasmodium vivax circumsporozoite (CS) protein were synthesised and used to assess their potential as vaccine candidates. Antigenicity studies were carried out using human blood samples from residents of a malaria-endemic area of Colombia, and immunogenicity was tested in Aotus monkeys. The N and C peptides spanned the total native amino and carboxyl flanking regions, whereas the R peptide corresponded to a construct based on the first central nona-peptide repeated in tandem three times and colinearly linked to a universal T-cell epitope (ptt-30) derived from tetanus toxin. All three peptides had been shown previously to contain several B-, T-helper (Th) and Cytotoxic T Lymphocytes (CTL) epitopes. Sixty-one percent of the human sera reacted with the R region, whereas 35 and 39% of the samples had antibodies against the N and C peptides, respectively. Human Peripheral Blood Mononuclear Cells (PBMC) showed higher levels of IFN-gamma than IL-4 when stimulated with peptides containing Th epitopes. Aotus monkeys immunised with the peptides formulated in either Montanide ISA720 or Freund's adjuvants produced strong antibody responses that recognised the peptide immunogens and the native circumsporozoite protein on sporozoites. Additionally, high IFN-gamma production was induced when Aotus lymphocytes were stimulated in vitro with each of the three peptides. We observed boosting of antibody responses and IFN-gamma production by exposure to live sporozoites. These results confirm the high antigenicity and immunogenicity of such synthetic polypeptides and underline their vaccine potential.
authors.affiliation: Institute of Immunology, University of Valle, AA 25574 Cali, Colombia. sherrera@inmuno.org
authors.forename: Sócrates
authors.initials: S
authors.lastname: Herrera
authors.forename: Anilza
authors.initials: A
authors.lastname: Bonelo
authors.forename: Blanca Liliana
authors.initials: BL
authors.lastname: Perlaza
authors.forename: Anais Zully
authors.initials: AZ
authors.lastname: Valencia
authors.forename: Catherine
authors.initials: C
authors.lastname: Cifuentes
authors.forename: Silvia
authors.initials: S
authors.lastname: Hurtado
authors.forename: Gustavo
authors.initials: G
authors.lastname: Quintero
authors.forename: José Alejandro
authors.initials: JA
authors.lastname: López
authors.forename: Giampietro
authors.initials: G
authors.lastname: Corradin
authors.forename: Myriam
authors.initials: M
authors.lastname: Arévalo-Herrera
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis; D000953:Antigens, Protozoan / Q000276:immunology*; D016645:Aotidae; D002648:Child; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D006801:Humans; D007114:Immunization; D017780:Malaria Vaccines / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000276:immunology; D010966:Plasmodium vivax / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016207:Cytokines; D017780:Malaria Vaccines; D010446:Peptide Fragments; D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan