Identification and characterization of CD4+ T-cell epitopes on GapC protein of Streptococcus dysgalactiae. (February 2016)

• Record Type: Journal Article
• Authors: Yao, Di; Zhang, Hua; Wang, Xintong; Yu, Simiao; Wei, Yuhua; Liu, Wei; Wang, Jiannan; Chen, Xiaoting; Zhang, Zhenghai; Sun, Hunan; Yu, Liquan; Ma, Jinzhu; Tong, Chunyu; Song, Baifen; Cui, Yudong
• Is Part Of: Microbial pathogenesis. Volume 91(2016)
• Page Start: 46
• Page End: 53
• Publication Date: 2016-02
• Subjects: Streptococcus dysgalactiae -- GapC -- CD4+ T-cell epitope; Pathogenic microorganisms -- Periodicals; Pathology, Molecular -- Periodicals; Communicable Diseases -- microbiology -- Periodicals; Communicable Diseases -- parasitology -- Periodicals; Micro-organismes pathogènes -- Périodiques; Pathologie moléculaire -- Périodiques; Electronic journals; 616.9041
• DOI: 10.1016/j.micpath.2015.11.025
• Languages: English
• ISSNs: 0882-4010

Abstract

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. Highlights: Two novel Streptococcus dysgalactiae GapC CD4 + T-cell epitopes were for the first time identified. Two epitopes, GapC63–77 and GapC96–110, preferentially elicited polarized Th1 or Th17-type responses. Our findings are available for further study of epitope-based vaccines.