title: Immunogenicity evaluation of a rationally designed polytope construct encoding HLA-A*0201 restricted epitopes derived from Leishmania major related proteins in HLA-A2/DR1 transgenic mice: steps toward polytope vaccine.
abstract: BACKGROUND
  There are several reports demonstrating the role of CD8 T cells against Leishmania species. Therefore peptide vaccine might represent an effective approach to control the infection. We developed a rational polytope-DNA construct encoding immunogenic HLA-A2 restricted peptides and validated the processing and presentation of encoded epitopes in a preclinical mouse model humanized for the MHC-class-I and II.
  
  
  RESULTS
  HLA-A*0201 restricted epitopes from LPG-3, LmSTI-1, CPB and CPC along with H-2Kd restricted peptides, were lined-up together as a polytope string in a DNA construct. Polytope string was rationally designed by harnessing advantages of ubiquitin, spacers and HLA-DR restricted Th1 epitope. Endotoxin free pcDNA plasmid expressing the polytope was inoculated into humanized HLA-DRB1*0101/HLA-A*0201 transgenic mice intramuscularly 4 days after Cardiotoxin priming followed by 2 boosters at one week interval. Mice were sacrificed 10 days after the last booster, and splenocytes were subjected to ex-vivo and in-vitro evaluation of specific IFN-γ production and in-vitro cytotoxicity against individual peptides by ELISpot and standard chromium-51 (51Cr) release assay respectively. 4 H-2Kd and 5 HLA-A*0201 restricted peptides were able to induce specific CD8 T cell responses in BALB/C and HLA-A2/DR1 mice respectively. IFN-γ and cytolytic activity together discriminated LPG-3-P1 as dominant, LmSTI-1-P3 and LmSTI-1-P6 as subdominant with both cytolytic activity and IFN-γ production, LmSTI-1-P4 and LPG-3-P5 as subdominant with only IFN-γ production potential.
  
  
  CONCLUSIONS
  Here we described a new DNA-polytope construct for Leishmania vaccination encompassing immunogenic HLA-A2 restricted peptides. Immunogenicity evaluation in HLA-transgenic model confirmed CD8 T cell induction with expected affinities and avidities showing almost efficient processing and presentation of the peptides in relevant preclinical model. Further evaluation will determine the efficacy of this polytope construct protecting against infectious challenge of Leishmania. Fortunately HLA transgenic mice are promising preclinical models helping to speed up immunogenicity analysis in a human related mouse model.
authors.affiliation: Molecular Immunology and Vaccine Research Lab, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Negar
authors.initials: N
authors.lastname: Seyed
authors.affiliation: Molecular Immunology and Vaccine Research Lab, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Tahereh
authors.initials: T
authors.lastname: Taheri
authors.affiliation: INSERM U1098, Unité Mixte de Recherche, Besançon, France; Etablissement Français du Sang de Bourgogne Franche-Comté, Besançon, France; Université de Franche-Comté, Besançon, France.
authors.forename: Charline
authors.initials: C
authors.lastname: Vauchy
authors.affiliation: INSERM U1098, Unité Mixte de Recherche, Besançon, France; Etablissement Français du Sang de Bourgogne Franche-Comté, Besançon, France; Université de Franche-Comté, Besançon, France.
authors.forename: Magalie
authors.initials: M
authors.lastname: Dosset
authors.affiliation: INSERM U1098, Unité Mixte de Recherche, Besançon, France; Etablissement Français du Sang de Bourgogne Franche-Comté, Besançon, France; Université de Franche-Comté, Besançon, France.
authors.forename: Yann
authors.initials: Y
authors.lastname: Godet
authors.affiliation: Department of Electron Microscopy and Clinical Research, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Eslamifar
authors.affiliation: School of Medicine, Leishmaniasis Research Center, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Iraj
authors.initials: I
authors.lastname: Sharifi
authors.affiliation: INSERM U1098, Unité Mixte de Recherche, Besançon, France; Etablissement Français du Sang de Bourgogne Franche-Comté, Besançon, France; Université de Franche-Comté, Besançon, France; CHRU de Besançon, Service d'Oncologie, Besançon, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Adotevi
authors.affiliation: INSERM U1098, Unité Mixte de Recherche, Besançon, France; Etablissement Français du Sang de Bourgogne Franche-Comté, Besançon, France; Université de Franche-Comté, Besançon, France; CHRU de Besançon, Service d'Oncologie, Besançon, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Borg
authors.affiliation: INSERM U1098, Unité Mixte de Recherche, Besançon, France; Etablissement Français du Sang de Bourgogne Franche-Comté, Besançon, France; Université de Franche-Comté, Besançon, France; CHRU de Besançon, Service de pédiatrie, Besançon, France.
authors.forename: Pierre Simon
authors.initials: PS
authors.lastname: Rohrlich
authors.affiliation: Molecular Immunology and Vaccine Research Lab, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Sima
authors.initials: S
authors.lastname: Rafati
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D015789:HLA-A2 Antigen / Q000235:genetics*; D018320:Leishmania major / Q000276:immunology*; D007896:Leishmaniasis / Q000276:immunology / Q000517:prevention & control*; D054332:Leishmaniasis Vaccines / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic
chemical_list: D018984:Epitopes, T-Lymphocyte; C435939:HLA-A*02:01 antigen; D015789:HLA-A2 Antigen; D054332:Leishmaniasis Vaccines