title: TLR5-dependent immunogenicity of a recombinant fusion protein containing an immunodominant epitope of malarial circumsporozoite protein and the FliC flagellin of Salmonella Typhimurium.
abstract: Recently, we described the improved immunogenicity of new malaria vaccine candidates based on the expression of fusion proteins containing immunodominant epitopes of merozoites and Salmonella enterica serovar Typhimurium flagellin (FliC) protein as an innate immune agonist. Here, we tested whether a similar strategy, based on an immunodominant B-cell epitope from malaria sporozoites, could also generate immunogenic fusion polypeptides. A recombinant His6-tagged FliC protein containing the C-terminal repeat regions of the VK210 variant of Plasmodium vivax circumsporozoite (CS) protein was constructed. This recombinant protein was successfully expressed in Escherichia coli as soluble protein and was purified by affinity to Ni-agarose beads followed by ion exchange chromatography. A monoclonal antibody specific for the CS protein of P. vivax sporozoites (VK210) was able to recognise the purified protein. C57BL/6 mice subcutaneously immunised with the recombinant fusion protein in the absence of any conventional adjuvant developed protein-specific systemic antibody responses. However, in mice genetically deficient in expression of TLR5, this immune response was extremely low. These results extend our previous observations concerning the immunogenicity of these recombinant fusion proteins and provide evidence that the main mechanism responsible for this immune activation involves interactions with TLR5, which has not previously been demonstrated for any recombinant FliC fusion protein.
authors: Centro de Terapia Celular e Molecular, Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Mirassol 207, 04044-010 São Paulo, SP, Brasil.
authors: Ariane Guglielmi Ariza
authors: AG
authors: Camacho
authors: Laís Helena
authors: LH
authors: Teixeira
authors: Daniel Youssef
authors: DY
authors: Bargieri
authors: Silvia Beatriz
authors: SB
authors: Boscardin
authors: Irene da Silva
authors: IS
authors: Soares
authors: Ruth Sonntag
authors: RS
authors: Nussenzweig
authors: Victor
authors: V
authors: Nussenzweig
authors: Mauricio Martins
authors: MM
authors: Rodrigues
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000276:immunology; D018985:Epitopes, B-Lymphocyte / Q000276:immunology / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000276:immunology; D005408:Flagellin / Q000276:immunology* / Q000378:metabolism; D016056:Immunodominant Epitopes / Q000276:immunology* / Q000378:metabolism; D017780:Malaria Vaccines / Q000276:immunology* / Q000378:metabolism; D016780:Malaria, Vivax / Q000276:immunology / Q000517:prevention & control*; D051379:Mice; D008810:Mice, Inbred C57BL; D010963:Plasmodium falciparum / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000276:immunology* / Q000378:metabolism; D012486:Salmonella typhimurium / Q000276:immunology* / Q000378:metabolism; D051198:Toll-Like Receptor 5 / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D018985:Epitopes, B-Lymphocyte; D029968:Escherichia coli Proteins; C516095:FliC protein, E coli; D016056:Immunodominant Epitopes; D017780:Malaria Vaccines; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D051198:Toll-Like Receptor 5; D005408:Flagellin