Giuseppe
Emeritus
[Source: PLoS ONE, full text: (LINK). Abstract, edited.]
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Prediction and Identification of T Cell Epitopes in the H5N1 Influenza Virus Nucleoprotein in Chicken
by Yanxia Hou, Yingying Guo, Chunyan Wu, Nan Shen, Yongping Jiang, Jingfei Wang
T cell epitopes can be used for the accurate monitoring of avian influenza virus (AIV) immune responses and the rational design of vaccines. No T cell epitopes have been previously identified in the H5N1 AIV virus nucleoprotein (NP) in chickens. For the first time, this study used homology modelling techniques to construct three-dimensional structures of the peptide-binding domains of chicken MHC class Ι molecules for four commonly encountered unique haplotypes, i.e., B4, B12, B15, and B19. H5N1 AIV NP was computationally parsed into octapeptides or nonapeptides according to the peptide-binding motifs of MHC class I molecules of the B4, B12, B15 and B19 haplotypes. Seventy-five peptide sequences were modelled and their MHC class I molecule-binding abilities were analysed by molecular docking. Twenty-five peptides (Ten for B4, six for B12, two for B15, and seven for B19) were predicted to be potential T cell epitopes in chicken. Nine of these peptides and one unrelated peptide were manually synthesized and their T cell responses were tested in vitro. Spleen lymphocytes were collected from SPF chickens that had been immunised with a NP-expression plasmid, pCAGGS-NP, and they were stimulated using the synthesized peptides. The secretion of chicken IFN-γ and the proliferation of CD8<SUP>+</SUP> T cells were tested using an ELISA kit and flow cytometry, respectively. The significant secretion of chicken IFN-γ and proliferation of CD8<SUP>+</SUP> T lymphocytes increased by 13.7% and 11.9% were monitored in cells stimulated with peptides NP<SUB>89?97</SUB> and NP<SUB>198?206</SUB>, respectively. The results indicate that peptides NP<SUB>89?97</SUB> (PKKTGGPIY) and NP<SUB>198?206</SUB> (KRGINDRNF) are NP T cell epitopes in chicken of certain haplotypes. The method used in this investigation is applicable to predicting T cell epitopes for other antigens in chicken, while this study also extends our understanding of the mechanisms of the immune response to AIV in chicken.
-by Yanxia Hou, Yingying Guo, Chunyan Wu, Nan Shen, Yongping Jiang, Jingfei Wang
T cell epitopes can be used for the accurate monitoring of avian influenza virus (AIV) immune responses and the rational design of vaccines. No T cell epitopes have been previously identified in the H5N1 AIV virus nucleoprotein (NP) in chickens. For the first time, this study used homology modelling techniques to construct three-dimensional structures of the peptide-binding domains of chicken MHC class Ι molecules for four commonly encountered unique haplotypes, i.e., B4, B12, B15, and B19. H5N1 AIV NP was computationally parsed into octapeptides or nonapeptides according to the peptide-binding motifs of MHC class I molecules of the B4, B12, B15 and B19 haplotypes. Seventy-five peptide sequences were modelled and their MHC class I molecule-binding abilities were analysed by molecular docking. Twenty-five peptides (Ten for B4, six for B12, two for B15, and seven for B19) were predicted to be potential T cell epitopes in chicken. Nine of these peptides and one unrelated peptide were manually synthesized and their T cell responses were tested in vitro. Spleen lymphocytes were collected from SPF chickens that had been immunised with a NP-expression plasmid, pCAGGS-NP, and they were stimulated using the synthesized peptides. The secretion of chicken IFN-γ and the proliferation of CD8<SUP>+</SUP> T cells were tested using an ELISA kit and flow cytometry, respectively. The significant secretion of chicken IFN-γ and proliferation of CD8<SUP>+</SUP> T lymphocytes increased by 13.7% and 11.9% were monitored in cells stimulated with peptides NP<SUB>89?97</SUB> and NP<SUB>198?206</SUB>, respectively. The results indicate that peptides NP<SUB>89?97</SUB> (PKKTGGPIY) and NP<SUB>198?206</SUB> (KRGINDRNF) are NP T cell epitopes in chicken of certain haplotypes. The method used in this investigation is applicable to predicting T cell epitopes for other antigens in chicken, while this study also extends our understanding of the mechanisms of the immune response to AIV in chicken.
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