Proteolytic Cleavage of the Plasmodium falciparum Circumsporozoite Protein Is a Target of Protective Antibodies

J Infect Dis. 2015 Oct 1;212(7):1111-9. doi: 10.1093/infdis/jiv154. Epub 2015 Mar 11.


Studies in animals and human volunteers demonstrate that antibodies against the repeat-region of the Plasmodium circumsporozoite protein (CSP) abrogate sporozoite infection. However, the realization that the N- and C- terminal regions flanking the repeats play essential roles in parasite infectivity raised the possibility that they could be targeted by protective antibodies. We characterized a monoclonal antibody (mAb5D5) specific for the N-terminus of the P. falciparum CSP, which inhibits the proteolytic cleavage of the CSP, a key requirement for parasite infection of hepatocytes. Adoptive transfer of mAb5D5 strongly inhibits the in vivo infection of sporozoites expressing the N-terminus of P. falciparum CSP, and this protection is greatly enhanced when combined with antirepeat antibodies. Our results show that antibodies interfering with molecular processes required for parasite infectivity can exert a strong in vivo protective activity and indicate that pre-erythrocytic vaccines against Plasmodium should include the CSP N-terminal region.

Keywords: CSP; P. falciparum; antibodies; malaria; sporozoites; vaccine.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antibodies, Monoclonal / immunology*
  • Antibodies, Protozoan / immunology*
  • Antibody Specificity
  • Epitopes / immunology
  • Female
  • Hepatocytes / parasitology
  • Humans
  • Malaria Vaccines / immunology*
  • Malaria, Falciparum / immunology
  • Malaria, Falciparum / prevention & control
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Plasmodium falciparum / immunology*
  • Protozoan Proteins / immunology*
  • Sporozoites / immunology


  • Antibodies, Monoclonal
  • Antibodies, Protozoan
  • Epitopes
  • Malaria Vaccines
  • Protozoan Proteins
  • circumsporozoite protein, Protozoan