Malaria Derived Glycosylphosphatidylinositol Anchor Enhances Anti-Pfs25 Functional Antibodies That Block Malaria Transmission

Biochemistry. 2018 Feb 6;57(5):516-519. doi: 10.1021/acs.biochem.7b01099. Epub 2018 Jan 16.

Abstract

Malaria, one of the most common vector borne human diseases, is a major world health issue. In 2015 alone, more than 200 million people were infected with malaria, out of which, 429 000 died. Even though artemisinin-based combination therapies (ACT) are highly effective at treating malaria infections, novel efforts toward development of vaccines to prevent transmission are still needed. Pfs25, a postfertilization stage parasite surface antigen, is a leading transmission-blocking vaccine (TBV) candidate. It is postulated that Pfs25 anchors to the cell membrane using a glycosylphosphatidylinositol (GPI) linker, which itself possesses pro-inflammatory properties. In this study, Escherichia coli derived extract (XtractCF+TM) was used in cell free protein synthesis [CFPS] to successfully express >200 mg/L of recombinant Pfs25 with a C-terminal non-natural amino acid (nnAA), namely, p-azidomethyl phenylalanine (pAMF), which possesses a reactive azide group. Thereafter, a unique conjugate vaccine (CV), namely, Pfs25-GPI was generated with dibenzocyclooctyne (DBCO) derivatized glycan core of malaria GPI using a simple but highly efficient copper free click chemistry reaction. In mice immunized with Pfs25 or Pfs25-GPI, the Pfs25-GPI group showed significantly higher titers compared to the Pfs25 group. Moreover, only purified IgGs from Pfs25-GPI group were able to significantly block transmission of parasites to mosquitoes, as judged by a standard membrane feeding assay [SMFA]. To our knowledge, this is the first report of the generation of a CV using Pfs25 and malaria specific GPI where the GPI is shown to enhance the ability of Pfs25 to elicit transmission blocking antibodies.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibody Formation
  • Glycosylphosphatidylinositols / immunology
  • Glycosylphosphatidylinositols / therapeutic use*
  • Humans
  • Immunization
  • Malaria
  • Malaria Vaccines / immunology
  • Malaria Vaccines / therapeutic use*
  • Malaria, Falciparum / immunology
  • Malaria, Falciparum / prevention & control*
  • Malaria, Falciparum / transmission
  • Mice
  • Plasmodium falciparum / immunology*
  • Protozoan Proteins / immunology
  • Protozoan Proteins / therapeutic use*
  • Vaccines, Conjugate / immunology
  • Vaccines, Conjugate / therapeutic use
  • Vaccines, Synthetic / immunology
  • Vaccines, Synthetic / therapeutic use

Substances

  • Glycosylphosphatidylinositols
  • Malaria Vaccines
  • Pfs25 protein, Plasmodium falciparum
  • Protozoan Proteins
  • Vaccines, Conjugate
  • Vaccines, Synthetic