Synthesis, solution structure and immune recognition of an epidermal growth factor-like domain from Plasmodium falciparum merozoite surface protein-1

Chembiochem. 2006 Dec;7(12):1943-50. doi: 10.1002/cbic.200600357.

Abstract

The Plasmodium falciparum merozoite surface protein-1 19 kDa fragment (MSP-1(19)) comprises two closely packed EGF-like domains (EGF=epidermal growth factor), each stabilized by three disulfide bonds. The native conformation of this protein is important for eliciting P. falciparum growth inhibitory antibodies. Here we show that the N-terminal EGF domain alone can be chemically synthesized and efficiently refolded to a native-like state, as shown by its solution structure as determined by NMR spectroscopy. In order to study its immunogenicity, the domain was coupled through its N terminus to a phospholipid and incorporated into reconstituted influenza virus-like particles (virosomes). When used to immunize mice, the peptide-loaded virosomes elicited potent humoral immune responses that were shown by Western blots and immunofluorescence assays to cross-react with native MSP-1 on the surfaces of P. falciparum blood stage parasites. This opens the way for a medicinal chemistry-oriented approach to the study and optimization of the antigenicity of the protein as a potential malaria vaccine candidate, whilst exploiting the immunopotentiating properties of influenza virosomes as a delivery vehicle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Protozoan / blood
  • Antibody Formation
  • Antibody Specificity
  • Epidermal Growth Factor / immunology*
  • Immunologic Tests
  • Magnetic Resonance Spectroscopy
  • Merozoite Surface Protein 1 / chemistry*
  • Merozoite Surface Protein 1 / immunology
  • Mice
  • Mice, Inbred BALB C
  • Models, Molecular
  • Molecular Sequence Data
  • Peptide Fragments / chemical synthesis
  • Peptide Fragments / chemistry*
  • Peptide Fragments / immunology*
  • Plasmodium falciparum / chemistry*
  • Plasmodium falciparum / immunology
  • Protein Structure, Tertiary
  • Protein Subunits / chemistry*
  • Protein Subunits / immunology
  • Protozoan Proteins / chemistry*
  • Protozoan Proteins / immunology
  • Solutions / chemistry
  • Virosomes / administration & dosage
  • Virosomes / chemistry
  • Virosomes / immunology

Substances

  • Antibodies, Protozoan
  • Merozoite Surface Protein 1
  • Peptide Fragments
  • Protein Subunits
  • Protozoan Proteins
  • Solutions
  • Virosomes
  • Epidermal Growth Factor