雞球蟲次單位疫苗之開發

Development of chicken coccidiosis subunit vaccine

張惟淳(Wei-Chun Chang)

指導教授 ： 莊國賓

國立屏東科技大學/農學院/動物疫苗科技研究所/碩士(2015年)

https://doi.org/10.6346/NPUST.2015.00034

摘要

球蟲 (Coccidium) 是屬於艾美球蟲科 (Eimeria) ，艾美球蟲屬 (Eimeria) 的寄生性原蟲。球蟲主要感染出生3-6週齡內的雛雞，受球蟲感染雛雞的臨床症狀有腹瀉、血便、換肉率低等症狀，嚴重則導致死亡，對經濟構成很大的威脅。S , T , E , G 為球蟲的基因，許多文獻指出這四種基因經轉譯後的蛋白質可引發良好的免疫反應，因此為開發疫苗的重要關鍵。本研究已成功選殖這四種基因，並將S , T , E , G基因載入pET-28a載體表現蛋白，製成次單位疫苗 (SGET)。結果顯示，施打完疫苗後的組別 (SGET)，血清 (IgG) 及腸道中的抗體（IgA）相較於其他組具有極顯著性差異 ( p < 0.001 )。體重變化方面，在攻球蟲後，免疫組（施打疫苗後攻球蟲）的體重所增加的重量相較於控制組（未施打疫苗，直接攻球蟲）也較多，藉以上初步結果顯示，四個重組的球蟲蛋白具有發展成次單位疫苗之潛力。另一方面，為了加強疫苗效果，在第二次的動物實驗中，我們將SGET 疫苗結合本實驗室沈忻穎學長所製的重組干擾素-γ（IFN-γ），並進行免疫評估。干擾素-γ（IFN-γ）無論在先天免疫反應或後天免疫反應皆扮演重要角色，後天免疫反應中IFN-γ是Th1反應中重要的免疫調節因子，並且可以誘導B細胞產生抗體。結果顯示，免疫SGET＋IFN-γ後再感染球蟲的組別與控制組（僅感染球蟲）及僅施打SGET組別在體重變化方面，相較之下具有顯著性差異。在死亡率及感染後組織病變的程度上，免疫SGET＋IFN-γ的組別相較於控制組低很多。由此可證明，IFN-γ與SGET結合後仍然可發揮其免疫調節的功能，並提升疫苗的效力。

關鍵字

艾美球蟲 ； 次單位疫苗 ； S ； T ； E ； G ； 干擾素-γ ； 原核表現系統

並列摘要

Coccidium is a parasitic protozoon, belonging to the genus Eimeria of the family Eimeria. The main infected hosts of coccidian are chicks, which aged in 3-6 weeks. The clinical symptoms in the infected chicks include diarrhoea, bloody faeces, and inefficient feed conversion rate. The most serious is death. Coccidiosis has a severe economic impact on worldwide. S, T, E and G are important coccidia genes. Four translated protein can induce good immune response, and therefore critical for the development of vaccines. In this study, We have constructed S, T, E and G genes into pET-28a expression vector. The preliminary results indicate that the antibody titer of immunized rSGET is significantly higher than other groups. In the weight increase ratio, immunized rSGET is also higher than without immunized group after challenge with oocyst. Regarding to these results, rSGET may be potential for developing an effective subunit vaccine against Coccidium. In addition, to enhance immunity response we add the recombinant IFN- γ ( r IFN-γ) from our lab with rSGET for secondary animal experiment. IFN-γ plays the important role in innate immunity and adaptive immunity, especially that it is one of the immune factors to induce antibody production from B cell for TH1 response. In our result, it has significantly difference in body weight comparison to the group of immune rSGET & rIFN-γ then challenge with coccidiosis that compare with immune rSGET group and challenge group. In mortality rate and pathologic changes, the result shows that the group of immune rSGET & rIFN-γ was lower than other groups. These results suggest that the vaccine of rSGET combine with rIFN-γcan enhance immune

並列關鍵字

E.tenella ； E.maxima ； E.acervulina ； subunit vaccine ； S ； T ； E ； G

參考文獻

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