A Plasmodium falciparum candidate vaccine based on a six-antigen polyprotein encoded by recombinant poxviruses

Proc Natl Acad Sci U S A. 2004 Jan 6;101(1):290-5. doi: 10.1073/pnas.0307158101. Epub 2003 Dec 23.

Abstract

To generate broadly protective T cell responses more similar to those acquired after vaccination with radiation-attenuated Plasmodium falciparum sporozoites, we have constructed candidate subunit malaria vaccines expressing six preerythrocytic antigens linked together to produce a 3240-aa-long polyprotein (L3SEPTL). This polyprotein was expressed by a plasmid DNA vaccine vector (DNA) and by two attenuated poxvirus vectors, modified vaccinia virus Ankara (MVA) and fowlpox virus of the FP9 strain. MVAL3SEPTL boosted anti-thrombospondin-related adhesive protein (anti-TRAP) and anti-liver stage antigen 1 (anti-LSA1) CD8(+) T cell responses when primed by single antigen TRAP- or LSA1-expressing DNAs, respectively, but not by DNA-L3SEPTL. However, prime boost regimes involving two heterologous viral vectors expressing L3SEPTL induced a strong cellular response directed against an LSA1 peptide located in the C-terminal region of the polyprotein. Peptide-specific T cells secreted IFN-gamma and were cytotoxic. IFN-gamma-secreting T cells specific for each of the six antigens were induced after vaccination with L3SEPTL, supporting the use of polyprotein inserts to induce multispecific T cells against P. falciparum. The use of polyprotein constructs in nonreplicating poxviruses should broaden the target antigen range of vaccine-induced immunity and increase the number of potential epitopes available for immunogenetically diverse human populations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Protozoan / genetics
  • CD8-Positive T-Lymphocytes / immunology
  • Cytotoxicity, Immunologic
  • Female
  • Fowlpox virus / genetics
  • Genetic Vectors
  • Interferon-gamma / biosynthesis
  • Malaria Vaccines / genetics
  • Malaria Vaccines / immunology*
  • Malaria, Falciparum / immunology*
  • Malaria, Falciparum / prevention & control*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Plasmodium falciparum / genetics
  • Plasmodium falciparum / immunology*
  • Protozoan Proteins / genetics
  • Protozoan Proteins / immunology
  • Vaccines, DNA / genetics
  • Vaccines, DNA / immunology
  • Vaccinia virus / genetics

Substances

  • Antigens, Protozoan
  • Malaria Vaccines
  • Protozoan Proteins
  • Vaccines, DNA
  • Interferon-gamma