Construction of Transgenic Plasmodium berghei as a Model for Evaluation of Blood-Stage Vaccine Candidate of Plasmodium falciparum Chimeric Protein 2.9
Open Access
- 3 September 2009
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 4 (9), e6894
- https://doi.org/10.1371/journal.pone.0006894
Abstract
The function of the 19 kDa C-terminal region of the merozoite surface protein 1 (MSP1-19) expressed by Plasmodium has been demonstrated to be conserved across distantly related Plasmodium species. The green fluorescent protein (GFP) is a reporter protein that has been widely used because it can be easily detected in living organisms by fluorescence microscopy and flow cytometry. In this study, we used gene targeting to generate transgenic P. berghei (Pb) parasites (designated as PfMSP1-19Pb) that express the MSP1-19 of P. falciparum (Pf) and the GFP reporter protein simultaneously. The replacement of the PbMSP1-19 locus by PfMSP1-19 was verified by PCR and Southern analysis. The expression of the chimeric PbfMSP-1 and the GFP was verified by Western blot and fluorescence microscopy, respectively. Moreover, GFP-expressing transgenic parasites in blood stages can be readily differentiated from other blood cells using flow cytometry. A comparion of growth rates between wild-type and the PfMSP1-19Pb transgenic parasite indicated that the replacement of the MSP1-19 region and the expression of the GFP protein were not deleterious to the transgenic parasites. We used this transgenic mouse parasite as a murine model to evaluate the protective efficacy in vivo of specific IgG elicited by a PfCP-2.9 malaria vaccine that contains the PfMSP1-19. The BALB/c mice passively transferred with purified rabbit IgG to the PfCP-2.9 survived a lethal challenge of the PfMSP1-19Pb transgenic murine parasites, but not the wild-type P. berghei whereas the control mice passively transferred with purified IgG obtained from adjuvant only-immunized rabbits were vulnerable to both transgenic and wild-type infections. We generated a transgenic P. berghei line that expresses PfMSP1-19 and the GFP reporter gene simultaneously. The availability of this parasite line provides a murine model to evaluate the protective efficacy in vivo of anti-MSP1-19 antibodies, including, potentially, those elicited by the PfCP-2.9 malaria vaccine in human volunteers.Keywords
This publication has 34 references indexed in Scilit:
- Murine Model for Assessment of Plasmodium falciparum Transmission-Blocking Vaccine Using Transgenic Plasmodium berghei Parasites Expressing the Target Antigen Pfs25Infection and Immunity, 2008
- Safety and Immunogenicity of a Malaria Vaccine, Plasmodium falciparum AMA-1/MSP-1 Chimeric Protein Formulated in Montanide ISA 720 in Healthy AdultsPLOS ONE, 2008
- A review of human vaccine research and development: MalariaVaccine, 2006
- Selection by flow-sorting of genetically transformed, GFP-expressing blood stages of the rodent malaria parasite, Plasmodium bergheiNature Protocols, 2006
- Immunogenicity and protective efficacy of Escherichia coli expressed Plasmodium falciparum merozoite surface protein-142 using human compatible adjuvantsVaccine, 2006
- The global distribution of clinical episodes of Plasmodium falciparum malariaNature, 2005
- The Fine Specificity, but Not the Invasion Inhibitory Activity, of 19-Kilodalton Merozoite Surface Protein 1-Specific Antibodies Is Associated with Resistance to Malarial Parasitemia in a Cross-Sectional Survey in The GambiaInfection and Immunity, 2004
- A New Rodent Model to Assess Blood Stage Immunity to the Plasmodium falciparum Antigen Merozoite Surface Protein 119 Reveals a Protective Role for Invasion Inhibitory AntibodiesThe Journal of Experimental Medicine, 2003
- Development and Use of Fluorescent Protein Markers in Living CellsScience, 2003
- Towards a blood-stage vaccine for malaria: are we following all the leads?Nature Reviews Immunology, 2001