Department of Biochemistry, All India Institute of Medical Sciences, New Delhi 110029, India.
Comp Immunol Microbiol Infect Dis. 2013 Jul;36(4):365-78. doi: 10.1016/j.cimid.2013.01.002. Epub 2013 Mar 7.
YscF antigen, a type III secretion protein has recently been shown partial protection in murine model. Five peptides of YscF antigen were predicted using DNASTAR and T-cell prediction software. Peptides were synthesised and authenticated using competitive, direct binding immunoassay with anti YscF/peptide sera raised in mice. Peptide P1 and P2 were found to be B cell epitope while P3 was minor B cell epitope. P4 peptide was a pure T cell epitope based on lymphoproliferative response, cytokines profile and T-bet expression. Furthermore, with an intention to enhance immunogenicity, three B-T constructs were designed between the above epitopes. Conjugate B1T1 and B2T1 showed higher serum IgG/IgA titre, respectively, as well as high secretory IgA plus secretory component (Sc) both in lung and intestinal washes. Also, these conjugates showed high T-cell proliferation in addition to higher Th1 type cytokines (IFN-γ and IL-2) in cells obtained from spleen, lamina propria and Peyer's patches. B3T1 stimulated cells showed moderate levels of IFN-γ and IL-2 but higher levels of IL-4. This study demonstrates superior immunogen of B1T1 and B2T1 of YscF antigen to be exploited as vaccine candidate for plague.
YscF 抗原是一种 III 型分泌蛋白，最近在小鼠模型中显示出部分保护作用。使用 DNASTAR 和 T 细胞预测软件预测了 YscF 抗原的 5 个肽段。使用竞争性、直接结合免疫测定法，用抗 YscF/肽血清对肽段进行合成和验证，该血清是在小鼠中产生的。发现肽段 P1 和 P2 是 B 细胞表位，而 P3 是次要 B 细胞表位。P4 肽是基于淋巴细胞增殖反应、细胞因子谱和 T 细胞转录因子表达的纯 T 细胞表位。此外，为了增强免疫原性，在上述表位之间设计了三个 B-T 构建体。B1T1 和 B2T1 缀合物分别显示出更高的血清 IgG/IgA 滴度，以及在肺和肠灌洗液中更高的分泌型 IgA 加分泌成分（Sc）。此外，这些缀合物在脾、固有层和派尔氏斑中获得的细胞中显示出更高的 T 细胞增殖，以及更高的 Th1 型细胞因子（IFN-γ 和 IL-2）。B3T1 刺激的细胞显示出中等水平的 IFN-γ 和 IL-2，但更高水平的 IL-4。本研究表明，YscF 抗原的 B1T1 和 B2T1 具有更好的免疫原性，可以作为鼠疫疫苗候选物进行开发。
