title: In silico analysis of six known Leishmania major antigens and in vitro evaluation of specific epitopes eliciting HLA-A2 restricted CD8 T cell response.
abstract: BACKGROUND
  As a potent CD8(+) T cell activator, peptide vaccine has found its way in vaccine development against intracellular infections and cancer, but not against leishmaniasis. The first step toward a peptide vaccine is epitope mapping of different proteins according to the most frequent HLA types in a population.
  
  
  RESULTS
  Six Leishmania (L.) major-related candidate antigens (CPB,CPC,LmsTI-1,TSA,LeIF and LPG-3) were screened for potential CD8(+) T cell activating 9-mer epitopes presented by HLA-A*0201 (the most frequent HLA-A allele). Online software including SYFPEITHI, BIMAS, EpiJen, Rankpep, nHLApred, NetCTL and Multipred were used. Peptides were selected only if predicted by almost all programs, according to their predictive scores. Pan-A2 presentation of selected peptides was confirmed by NetMHCPan1.1. Selected peptides were pooled in four peptide groups and the immunogenicity was evaluated by in vitro stimulation and intracellular cytokine assay of PBMCs from HLA-A2(+) individuals recovered from L. major. HLA-A2(-) individuals recovered from L. major and HLA-A2(+) healthy donors were included as control groups. Individual response of HLA-A2(+) recovered volunteers as percent of CD8(+)/IFN-γ(+) T cells after in vitro stimulation against peptide pools II and IV was notably higher than that of HLA-A2(-) recovered individuals. Based on cutoff scores calculated from the response of HLA-A2(-) recovered individuals, 31.6% and 13.3% of HLA-A2(+) recovered persons responded above cutoff in pools II and IV, respectively. ELISpot and ELISA results confirmed flow cytometry analysis. The response of HLA-A2(-) recovered individuals against peptide pools I and III was detected similar and even higher than HLA-A2(+) recovered individuals.
  
  
  CONCLUSIONS
  Using in silico prediction we demonstrated specific response to LmsTI-1 (pool II) and LPG-3- (pool IV) related peptides specifically presented in HLA-A*0201 context. This is among the very few reports mapping L. major epitopes for human HLA types. Studies like this will speed up polytope vaccine idea towards leishmaniasis.
authors: Molecular Immunology and Vaccine Research Lab, Pasteur Institute of Iran, Tehran, Iran.
authors: Negar
authors: N
authors: Seyed
authors: Farnaz
authors: F
authors: Zahedifard
authors: Shima
authors: S
authors: Safaiyan
authors: Elham
authors: E
authors: Gholami
authors: Fatemeh
authors: F
authors: Doustdari
authors: Kayhan
authors: K
authors: Azadmanesh
authors: Maryam
authors: M
authors: Mirzaei
authors: Nasir
authors: N
authors: Saeedi Eslami
authors: Akbar
authors: A
authors: Khadem Sadegh
authors: Ali
authors: A
authors: Eslami Far
authors: Iraj
authors: I
authors: Sharifi
authors: Sima
authors: S
authors: Rafati
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000953:Antigens, Protozoan / Q000235:genetics* / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D002648:Child; D019295:Computational Biology / Q000379:methods; D016207:Cytokines / Q000378:metabolism; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D005260:Female; D015789:HLA-A2 Antigen / Q000276:immunology*; D006801:Humans; D018320:Leishmania major / Q000235:genetics* / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012984:Software; D055815:Young Adult
chemical_list: D000953:Antigens, Protozoan; D016207:Cytokines; D018984:Epitopes, T-Lymphocyte; D015789:HLA-A2 Antigen