Identification of Protective B-Cell Epitopes within the Novel Malaria Vaccine Candidate Plasmodium falciparum Schizont Egress Antigen 1

Clin Vaccine Immunol. 2017 Jul 5;24(7):e00068-17. doi: 10.1128/CVI.00068-17. Print 2017 Jul.

Abstract

Naturally acquired antibodies to Plasmodium falciparum schizont egress antigen 1 (PfSEA-1A) are associated with protection against severe malaria in children. Vaccination of mice with SEA-1A from Plasmodium berghei (PbSEA-1A) decreases parasitemia and prolongs survival following P. berghei ANKA challenge. To enhance the immunogenicity of PfSEA-1A, we identified five linear B-cell epitopes using peptide microarrays probed with antisera from nonhuman primates vaccinated with recombinant PfSEA-1A (rPfSEA-1A). We evaluated the relationship between epitope-specific antibody levels and protection from parasitemia in a longitudinal treatment-reinfection cohort in western Kenya. Antibodies to three epitopes were associated with 16 to 17% decreased parasitemia over an 18-week high transmission season. We are currently designing immunogens to enhance antibody responses to these three epitopes.

Keywords: B-cell epitopes; PfSEA-1; malaria.

MeSH terms

  • Adolescent
  • Adult
  • Antibodies, Protozoan / blood*
  • Antigens, Protozoan / immunology*
  • Child
  • Cohort Studies
  • Epitope Mapping
  • Epitopes, B-Lymphocyte / immunology*
  • Humans
  • Kenya
  • Malaria, Falciparum / immunology*
  • Malaria, Falciparum / prevention & control
  • Male
  • Parasitemia / prevention & control
  • Protein Array Analysis
  • Protozoan Proteins / immunology*
  • Volunteers
  • Young Adult

Substances

  • Antibodies, Protozoan
  • Antigens, Protozoan
  • Epitopes, B-Lymphocyte
  • Protozoan Proteins
  • SEA-1 protein, Plasmodium falciparum