title: A Plasmodium falciparum candidate vaccine based on a six-antigen polyprotein encoded by recombinant poxviruses.
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.
authors.affiliation: Weatherall Institute of Molecular Medicine and Cellular Immunology, Nuffield Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom. eric.prieur@well.ox.ac.uk
authors.forename: Eric
authors.initials: E
authors.lastname: Prieur
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Gilbert
authors.forename: Joerg
authors.initials: J
authors.lastname: Schneider
authors.forename: Anne C
authors.initials: AC
authors.lastname: Moore
authors.forename: Eric G
authors.initials: EG
authors.lastname: Sheu
authors.forename: Nilu
authors.initials: N
authors.lastname: Goonetilleke
authors.forename: Kathryn J H
authors.initials: KJ
authors.lastname: Robson
authors.forename: Adrian V S
authors.initials: AV
authors.lastname: Hill
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D005260:Female; D005587:Fowlpox virus / Q000235:genetics; D005822:Genetic Vectors; D007371:Interferon-gamma / Q000096:biosynthesis; D017780:Malaria Vaccines / Q000235:genetics / Q000276:immunology*; D016778:Malaria, Falciparum / Q000276:immunology* / Q000517:prevention & control*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010963:Plasmodium falciparum / Q000235:genetics / Q000276:immunology*; D015800:Protozoan Proteins / Q000235:genetics / Q000276:immunology; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology; D014616:Vaccinia virus / Q000235:genetics
chemical_list: D000953:Antigens, Protozoan; D017780:Malaria Vaccines; D015800:Protozoan Proteins; D019444:Vaccines, DNA; D007371:Interferon-gamma