title: Identification of CD4+ T-cell epitopes on iron-regulated surface determinant B of Staphylococcus aureus.
abstract: Iron-regulated surface determinant B (IsdB) of Staphylococcus aureus (S. aureus) is a highly conserved surface protein that can induce protective CD4(+) T-cell immune response. A pivotal role of CD4(+) T-cells in effective immunity against S. aureus infection has been proved, but CD4(+) T-cell epitopes on the S. aureus IsdB have not been well identified. In this study, MHC binding assay was firstly used to predict CD4(+) T-cell epitopes on S. aureus IsdB protein, and six peptides were synthesized to validate the probable epitopes. Two novel IsdB CD4(+) T-cell epitopes, P1 (residues 159-178) and P4 (residues 287-306), were for the first time identified using CD4(+) T-cells obtained from IsdB-immunized C57BL/6 (H-2(b)) and BALB/c (H-2(d)) mice spleen based on cell proliferation and cytokines response. The results showed that P1 and P4 emulsified in Freund's adjuvant (FA) induced much higher cell proliferation compared with PBS emulsified in FA. CD4(+) T-cells stimulated with peptides P1 and P4 secreted significantly higher levels of IFN-γ and IL-17A. However, the level of the cytokine IL-4 almost remained unchanged, suggesting that P1 and P4 preferentially elicited polarized Th1-type responses. In addition, BALB/c mice just respond to P4 not P1, while C57BL/6 mice respond to P1 not P4, implying that epitope P1 and P4 were determined as H-2(b) and H-2(d) restricted epitope, respectively. Taken together, our data may provide an explanation of the IsdB-induced protection against S. aureus and highlight the possibility of developing the epitope-based vaccine against the S. aureus.
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Simiao
authors.initials: S
authors.lastname: Yu
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.affiliation: College of Animal Science and Veterinary Medicine, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Di
authors.initials: D
authors.lastname: Yao
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Xintong
authors.initials: X
authors.lastname: Wang
authors.affiliation: College of Animal Science and Veterinary Medicine, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Chen
authors.affiliation: College of Animal Science and Veterinary Medicine, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Wei
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Zhenghai
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Jiannan
authors.initials: J
authors.lastname: Wang
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Liquan
authors.initials: L
authors.lastname: Yu
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Hunan
authors.initials: H
authors.lastname: Sun
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Wu
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Yongzhong
authors.initials: Y
authors.lastname: Yu
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Baifen
authors.initials: B
authors.lastname: Song
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Jinzhu
authors.initials: J
authors.lastname: Ma
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China.
authors.forename: Chunyu
authors.initials: C
authors.lastname: Tong
authors.affiliation: College of Life Science and Technology, HeiLongJiang BaYi Agricultural University, Daqing 163319, China; College of Animal Science and Veterinary Medicine, HeiLongJiang BaYi Agricultural University, Daqing 163319, China. Electronic address: cuiyudong@yahoo.com.
authors.forename: Yudong
authors.initials: Y
authors.lastname: Cui
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D027682:Cation Transport Proteins / Q000276:immunology*; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D013211:Staphylococcus aureus / Q000276:immunology*
chemical_list: D027682:Cation Transport Proteins; D018984:Epitopes, T-Lymphocyte; C510010:IsdB protein, Staphylococcus aureus
keywords: IsdB protein; Staphylococcus aureus; T-cell epitope