出版年:

2002

研究生:

林家予

研究生(英文姓名):

Chia-Yu Lin

論文名稱:

以小鼠模式探討化膿性鏈球菌之寡月生 月太 膜透酉每 、鏈球菌溶血素S及鏈球菌溶血素O之角色

英文論文名稱:

Roles of oligopeptide permease、streptolysin S and streptolysin O of Streptococcus pyogenes infection in the murine model

指導教授:

吳俊忠

指導教授(英文姓名):

Jiunn-Jong Wu

學位類別:

碩士

校院名稱:

國立成功大學　

系所名稱:

微生物暨免疫學研究所

學號:

s46881034

學年度:

90

語文別:

中文

論文頁數:

0

關鍵詞:

化膿性鏈球菌 ; 寡月生 月太 膜透酉每 ; 鏈球菌溶血素S ; 鏈球菌溶血素O

英文關鍵詞:

Streptococcus pyogenes ; Oligopeptide permease ;
streptolysin S ; streptolysin O

被引用次數:

0

[ 摘要 ]

化膿性鏈球菌 (A群鏈球菌) 為革蘭氏陽性的細胞外致病菌，可以造成諸多化膿性或非化膿性的疾病。化膿性鏈球菌可以產生許多的致病毒力因數，而過去已有許多相關研究。寡月生 月太 膜透酉每 是附著在細胞膜上的蛋白並且屬於ABC-transporter群，對於其在化膿性鏈球菌的功能目前仍不清楚。我們實驗室先前的研究指出，中斷寡月生 月太 膜透酉每 基因會影響鏈球菌熱原性外毒素B、鏈球菌溶血素S、鏈球菌溶血素O及其他的致病毒力因數之產生，但和野生株比較下，其鏈球菌溶血素S及鏈球菌溶血素O的表現卻高出四倍之多。
本論文的研究進一步利用小鼠模式來探討寡月生 月太 膜透酉每 在 化膿性鏈球菌感染之角色。首先，將小鼠自皮下氣囊感染4 × 109 CFU菌量之化膿性鏈球菌後，每天觀察野生株、鏈球菌熱原性外毒素B突變株、寡月生 月太 膜透酉每突變株及寡月生 月太 膜透酉每回復株對小鼠的致死率。結果顯示一週後感染野生株及鏈球菌熱原性外毒素B突變株的小鼠死亡率達100﹪，而寡月生 月太 膜透酉每 突變株的小鼠兩週後仍有50﹪存活率。計算氣囊回抽液內細菌及浸潤細胞數目，發現寡月生 月太 膜透酉每 突變株的菌數隨時間增長而逐漸減少，但浸潤細胞數目在野生株與突變株之間並無明顯差異。進一步測定兩者對J774A.1巨噬細胞的抗吞噬能力，雖然野生株與突變株在抗吞噬的能力上並無顯著差異，但突變株被吞噬後較容易被巨噬細胞所清除，以上結果顯示寡月生 月太 膜透酉每 對於化膿性鏈球菌的感染十分重要。有趣的是，寡月生 月太 膜透酉每 突變株產生較多鏈球菌溶血素S及鏈球菌溶血素O，而這兩者皆屬於化膿性鏈球菌的可能毒力因數，但在我們的實驗中突變株並沒有造成小鼠較高的致死率，因此，我們也構築了鏈球菌溶血素S、鏈球菌溶血素O突變株、鏈球菌溶血素S和寡月生 月太 膜透酉每 雙重突變株以及鏈球菌溶血素O和寡月生月太 膜透酉每 雙重突變株來試圖釐清鏈球菌溶血素S、鏈球菌溶血素O與寡月生月太膜透酉每三者的關聯性；同樣以皮下氣囊感染4 × 109 CFU的細菌，鏈球菌溶血素S、鏈球菌溶血素O突變株及寡月生月太膜透酉每突變株於兩週後對小鼠存活率分別為25，50及66﹪，而兩雙重突變株的小鼠存活率幾乎達100﹪，因此我們認為在化膿性鏈球菌感染致死過程中，寡月生月太膜透酉每扮演較鏈球菌溶血素S及鏈球菌溶血素O更重要的角色，但由於寡月生月太膜透酉每的調控非常複雜，或許有其他未知的因數牽涉在內，仍待進一步研究。

[ 英文摘要 ]

Streptococcus pyogenes (group A streptococcus), a gram-positive extracellular pathogen, causes a variety of pyrogenic infections. S. pyogenes produces several virulence factors and many of them have been shown to contribute to its infection. Oligopeptide permease (Opp) is a membrane-associated protein and belongs to the ABC-transporter family. Its function in S. pyogenes is unclear. In our laboratory, previous study showed that disruption of the opp gene affected the productions of SPE B, streptolysin S (SLS), streptolysin O (SLO) and other virulence factors. The Opp mutant did not express SPE B, whereas productions of SLS and SLO were four-fold higher than that of the wild-type strain.
In this study, we determined the role of oligopeptide permease of S. pyogenes in mice. Bacteria (4 × 109 CFU) were inoculated into BALB/c mice via air pouch, and the mortality rates of mice inoculated with the wild-type strain, speB mutant, opp mutant, and opp revertant were measured. The results demonstrated that the wild-type strain caused 100﹪mortality on day 6, the speB mutant caused 100﹪on day 7, whereas the opp mutant caused only 50﹪mortality after two weeks. The opp revertant caused a mortality rate similar to that of the wild-type strain. The numbers of bacteria and infiltrated cells in the exudates from the air pouches of mice infected with opp mutant and wild-type strain were also compared. The number of the opp mutant in the exudates decreased whereas the number of infiltrated cells had no significant difference between wild-type strain and opp mutant. The anti-phagocytosis ability of the wild-type strain and opp mutant strain showed no significant difference. However, the number of the viable bacteria recovered from the phagocytes of the opp mutant were much less than that of the wild-type strain. These data suggest that Opp is important for the virulence of S. pyogenes in mice. Interestingly, the opp mutant secreted more SLS and SLO in our previous data. Since SLS and SLO are putative virulence factors of S. pyogenes, their roles seem to be controversial with our data in the murine model. In order to solve this question, SLS and SLO mutants were constructed. We compared the mortality rates of mice infected with the wild-type strain, Opp mutant, SLS mutant, SLO mutant, SLS-Opp double mutant, and SLO-Opp double mutant. The SLS mutant, SLO mutant and Opp mutant caused 25, 50, and 66﹪survival, respectively. Mice inoculated with the double mutants survived near 100﹪. Our results indicate that Opp is more important than either SLS or SLO in the group A streptococcal infection. Because the regulation of oligopeptide permease is very complex, further studies are required to understand the role of Opp in the murine model of group A streptococcal infection.