title: Identification and characterization of CD4⁺ T-cell epitopes on GapC protein of Streptococcus dysgalactiae.
abstract: The GapC protein is highly conserved surface dehydrogenase among Streptococcus dysgalactiae (S. dysgalactiae) and is shown to be involved in bacterial virulence. Immunization of GapC protein can induce specific CD4(+) T-cell immune responses and protect against S. dysgalactiae infection. However, there are no studies to identify immunodominant CD4(+) T-cell epitopes on GapC protein. In this study, in silico MHC affinity measurement method was firstly used to predict potential CD4(+) T-cell epitopes on GapC protein. Six predictive 15-mer peptides were synthesized and two novel GapC CD4(+) T-cell epitopes, GapC63-77 and GapC96-110, were for the first time identified using CD4(+) T-cells obtained from GapC-immunized BALB/c (H-2(d)) and C57BL/6 (H-2(b)) mice spleen based on cell proliferation and cytokines response. The results showed that peptides containing 63-77 and 96-110 induced significant antigen-specific CD4(+) T-cells proliferation response in vivo. At the same time, high levels of IFN-γ and IL-17A, as well as moderate levels of IL-10 and IL-4 were detected in CD4(+) T-cells isolated from both GapC and peptide-immunized mice in vivo, suggesting that GapC63-77 and GapC96-110 preferentially elicited polarized Th1/Th17-type responses. The characterization of GapC CD4(+) T-cell epitopes not only helps us understand its protective immunity, but also contributes to design effective T-cell epitope-based vaccine against S. dysgalactiae infection.
authors.affiliation: College of Animal Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China; College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China; College of Food Science, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Di
authors.initials: D
authors.lastname: Yao
authors.affiliation: College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.affiliation: College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Xintong
authors.initials: X
authors.lastname: Wang
authors.affiliation: College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Simiao
authors.initials: S
authors.lastname: Yu
authors.affiliation: College of Animal Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China; College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Wei
authors.affiliation: College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Jiannan
authors.initials: J
authors.lastname: Wang
authors.affiliation: College of Animal Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China; College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Chen
authors.affiliation: College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Zhenghai
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Hunan
authors.initials: H
authors.lastname: Sun
authors.affiliation: College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Liquan
authors.initials: L
authors.lastname: Yu
authors.affiliation: College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Jinzhu
authors.initials: J
authors.lastname: Ma
authors.affiliation: College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Chunyu
authors.initials: C
authors.lastname: Tong
authors.affiliation: College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China.
authors.forename: Baifen
authors.initials: B
authors.lastname: Song
authors.affiliation: College of Animal Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China; College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Xinfeng Road 5, Daqing 163319, China. Electronic address: cuiyudong@yahoo.com.
authors.forename: Yudong
authors.initials: Y
authors.lastname: Cui
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D013290:Streptococcal Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D013291:Streptococcus / Q000235:genetics / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D018984:Epitopes, T-Lymphocyte; C469817:GapC protein, Streptococcus
keywords: CD4(+) T-cell epitope; GapC; Streptococcus dysgalactiae