Protective immunity against Streptococcus pyogenes challenge in mice after immunization with fibronectin-binding protein.
Protective immunity against Streptococcus pyogenes challenge in mice after immunization with fibronectin-binding protein.
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DOI：
10.1086/498162
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发表时间：
2005-12
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影响因子：
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通讯作者：
Y. Terao;S. Okamoto;K. Kataoka;S. Hamada;S. Kawabata
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文献类型：
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作者：
Y. Terao;S. Okamoto;K. Kataoka;S. Hamada;S. Kawabata
背景技术化脓性链球菌的表面相关纤连蛋白(Fn)结合蛋白在细菌入侵上皮细胞中发挥重要作用。我们检查了 Fn 结合蛋白 FbaA 的功能域和保护性抗原性。方法 为了研究 FbaA 的功能域及其在化脓性链球菌上的定位，使用一系列重组谷胱甘肽 S-转移酶 (GST) 截短的 FbaA 蛋白进行免疫荧光显微镜检查、配体印迹和 Biacore 分析。用截短的蛋白质对小鼠进行免疫，以确定有助于防止化脓性链球菌感染的免疫原性结构域。结果配体印迹和 Biacore 分析表明，含有富含脯氨酸重复结构域 (RD) 的 FbaA 片段（而非 N 和 C 末端区域）具有 Fn 结合活性。免疫荧光显微镜检查结果表明，N 末端和 RD 暴露于外部区域，这表明 RD 作为活体生物体上的 Fn 结合元件。在 N 末端和 RD 免疫小鼠中有效诱导了特异性抗体，并在体外证明了针对化脓性链球菌的杀菌活性。在感染表达 FbaA 的血清型 M1 和 M49 菌株后，FbaA 免疫小鼠的存活时间明显长于 GST 免疫小鼠。结论 FbaA 的 Fn 结合 RD 和 N 末端是化脓性链球菌感染 M1 株的潜在候选疫苗。
BACKGROUND Surface-associated fibronectin (Fn)-binding proteins of Streptococcus pyogenes play an important role in the bacterial invasion of epithelial cells. We examined the functional domain and protective antigenicity of the Fn-binding protein FbaA. METHODS To investigate the functional domain of FbaA and its localization on S. pyogenes, a series of recombinant glutathione S-transferase (GST)-truncated FbaA proteins was used for immunofluorescent microscopy, ligand blotting, and Biacore analyses. Mice were immunized with the truncated proteins for the determination of the immunogenic domains that contribute to protection against S. pyogenes infection. RESULTS Ligand-blotting and Biacore analyses revealed that the FbaA fragments harboring a proline-rich repeat domain (RD), but not the N- and C-terminal regions, possessed Fn-binding activity. Immunofluorescent microscopy findings showed that the N terminus and RD were exposed to external regions, which suggests that the RD serves as a Fn-binding element on live organisms. Specific antibodies were efficiently induced in N terminus- and RD-immunized mice and demonstrated bactericidal activity against S. pyogenes in vitro. FbaA-immunized mice survived significantly longer than GST-immunized mice after infection with serotype M1 and M49 strains expressing FbaA. CONCLUSION The Fn-binding RD and N terminus of FbaA are potential vaccine candidates for M1 strains of S. pyogenes infection.