Glyceraldehyde-3-phosphate dehydrogenase C (GapC) of Streptococcus dysgalactiae (S. dysgalactiae) is a highly conserved surface protein that can induce a protective immune response against S. dysgalactiae infection. To investigate the immune response and protective efficacy induced by epitope-vaccines against S. dysgalactiae infection, we constructed epitope-vaccines GTB1, GB1B2, and GTB1B2 using a T cell epitope (GapC_63-77, abbreviated as GT) and two B cell epitopes (GapC_30-36, abbreviated as GB1, and GapC_97-103, abbreviated as GB2), which were identified in GapC_1-150 of S. dysgalactiae in tandem by a GSGSGS linker. BALB/c mice were immunized via an intramuscular injection with the epitope vaccines. The levels of the cytokines, IFN-γ, IL-4, and IL-17, secreted by splenic lymphocytes and the antibody levels in the sera of the immunized mice were detected by ELISA. The immunized mice were subsequently challenged with S. dysgalactiae, and the bacterial colonization in the immunized-mouse organs was examined using the plate counting method. The results showed that the level of the cytokines induced by GTB1B2 was lower than that induced by GapC_1-150, but higher than that induced by other epitope vaccines. The level of IgG induced by GTB1B2 was lower than that induced by GapC_1-150, but higher than the levels induced by other epitope vaccines. The bacterial colonization numbers in the organs of the mice immunized with GTB1B2 were higher those of the mice immunized with GapC_1-150, but significantly lower than those from the mice immunized with other epitope-vaccines. Our results demonstrated that the T cell and B cell epitopes in the epitope-vaccines worked synergistically against bacterial challenge. The multi-epitope vaccine, GTB1B2, could induce stronger cellular and humoral immune responses, and provide a better protective effect against S. dysgalactiae infection.

链球菌性dysgalactiae（S. dysgalactiae）的3-磷酸甘油醛脱氢酶C（GapC）是高度保守的表面蛋白，可以诱导针对性的S. dysgalactiae感染的保护性免疫反应。为了研究表位疫苗诱导的针对S. dysgalactiae感染的免疫应答和保护功效，我们使用T细胞表位（GapC _63-77，缩写为GT）和两个B细胞表位构建了表位疫苗GTB1，GB1B2和GTB1B2。（GAPC _30-36，缩写为GB1，和GAPC _97-103，缩写为GB2），这是在确定GAPC _1-150的停乳链球菌由GSGSGS链接器串联。通过肌内注射表位疫苗免疫BALB / c小鼠。通过ELISA检测脾淋巴细胞分泌的细胞因子，IFN-γ，IL-4和IL-17的水平以及免疫小鼠血清中的抗体水平。免疫小鼠随后用痢疾志贺氏菌攻击，并使用平板计数法检查免疫小鼠器官中的细菌定植。结果表明，GTB1B2诱导的细胞因子水平低于GapC _1-150诱导的细胞因子水平，但高于其他表位疫苗诱导的细胞因子水平。GTB1B2诱导的IgG水平低于GapC _1-150诱导的IgG水平，但高于其他表位疫苗诱导的水平。用GTB1B2免疫的小鼠器官中的细菌定殖数高于用GapC _1-150免疫的小鼠，但远低于用其他表位疫苗免疫的小鼠。我们的结果表明，表位疫苗中的T细胞和B细胞表位协同对抗细菌攻击。多表位疫苗GTB1B2可以诱导更强的细胞和体液免疫反应，并提供更好的针对S. dysgalactiae感染的保护作用。