猪链球菌之溶血素及细胞外因素重组蛋白之抗原性分析.doc

豬鏈球菌之溶血素及細胞外因素重組蛋白之抗原性分析 Evaluation on?the?Antigenicity of Recombinant?Suilysin and Extracellular Factor?of Streptococcus suis 研究生：周潤發 Narongrat Maliwong 指導老師: 朱純燕 Chu, Chun -Yen 李嘉偉 Lee, Jai -Wei 摘要 豬鏈球菌（Streptococcus suis, S. suis）第二血清型係一重要豬隻病原，它能造成諸如腦膜炎、 敗血症、 心內膜炎、 關節炎及敗血性休克等症狀,死亡率高。 本病原屬人畜共通， 以密集與豬隻接觸之人員風險較高。豬鏈球菌共有 35 種血清型， 其致病因子 110KDa 大小的細胞外因子（extracellular factor, EF）及 54~65 KDa 的溶血素（suilysin, Sly）可於部分血清型中表現， 分別由 epf 及sly 基因表現出。 而EF和SLY蛋白表現與否往往與高毒力第二血清型菌株有關， 但它們的功能目前仍不明。本篇研究目的為利用原核表現系統表現重組細胞外因子 rEFa 及溶血素 rSly 蛋白，以作為抗原製作次單位疫苗。結果可知單獨以 rEFa 免疫,經過 2 至4 週仍無法誘發抗原特異性抗體；然而，如再搭配全菌，rEFa 則能增強誘發抗體。另一方面，單獨以 rSly 免疫，經過 2 至 4 週能增加抗原特異性抗體產生。當 rEFa 及 rSly 搭配全菌，抗體的增加將是可預期的。REFa 雖無極佳免疫原性， 仍可做為評估商品化 ISA VG 佐劑效力之抗原。ISA 201 VG 組別可產生較高的特異性 rEFa 抗體力價，較其他組別具顯著性差異 P 0.05 。利用血清型第一型豬鏈球菌選殖 rEFa 及 rEFb 的重組蛋白混合 ISA 201 VG，結果顯示在單單施打 rEFa 或 rEFb 疫苗在施打後 2 及 4 週，可促使抗體產生，並且將 rEFa 混合 rEFb 免疫結果顯示可引起更高的抗體產生。 關鍵字：豬鏈球菌, Streptococcus suis、Suilysin 【Abstract】 Streptococcus suis S. suis serotype 2 is an important swine pathogen responsible for diverse infections, including meningitis, septicaemia, endocarditis, arthritis, and septic shock, and the mortality is high. It can be transmitted to human beings through close contact with sick pigs or carriers. Totally, thirty-five serotypes have been identified. The 110 kDa extracellular factor EF and the 54 to 65 kDa Suilysin Sly are expressed by some S. suis strains. EF and Sly are frequently associated with the highly virulent serotype 2 strains, but their functions are still unclear. The objective of this research is using recombinant EF rEFa from serotype 2, P2 , rEFa, rEFb from serotype 1, P1 , and Sly rSly from 14750, standard strain from BCRC proteins, expressed by a prokaryotic expression system, as the antigen to produce subunit vaccines. The results showed that immunization with rEFa alone in mice failed to trigger the production of antigen-specific antibody 2 and 4 weeks after the primary vaccination. However, when combined with