Anti-CTLA4 scFv, a Single-Chain Antibody, Protects the Expression of E. coli. beta-Galactosidase during Repeated Intramuscular Injections in Immune-Competent Mice

單鏈抗體anti-CTLA4 scFv保護重覆肌肉注射大腸桿菌半乳糖酶於免疫力正常小黑鼠體內之表達

劉安邦(An-Bang Liu) ； 羅博倫(Steve R Roffler)

《慈濟醫學雜誌》 18卷4期 (2006/08) Pp. 259-265

https://doi.org/10.6440/TZUCMJ.200608.0259

摘要

目的：本研究的目的是要探討毒殺T細胞相關第四抗原單鏈抗體－anti-CTLA4 scFv能否保護極具抗原性的大腸桿菌半乳糖酶經重覆肌肉注射時在免疫力正常的小黑鼠體內表達。材料與方法：我們將六至九週大且具正常免疫力的小黑鼠，C57BL/6分成兩組每組五隻，對照組在其左前腔骨肌注射溶於磷酸鹽緩衝溶液不含細菌內毒素的質體－pCBLacZ，DNA的濃度為1mg/mL，注射劑量為50微升(μL)，這個質體將表達大腸桿菌半乳糖酶以誘發局部的免疫反應。實驗組則除了注射pCBLacZ外還注射相同濃度相同劑量的另一質體－p4F10eB7，此質體可以在肌肉細胞表達anti-CTLA4 scFv。這些小鼠一共接受連續四次的肌肉注射，每次間隔一週。結果：我們在最後一次注射後第六天檢視小鼠的肌肉切片，發現具半乳糖酶活性的肌細胞數在對照組平均為1.40；實驗組為12.6，二者都有明顯炎性細胞浸潤的現象。結論：正常免疫力的小鼠經重覆肌肉注射質體，會對表達出來具抗原性的蛋白質產生免疫反應，進而破壞其表達，同時合併注射單鏈抗體－anti-CTLA4 scFv，可以保護外來蛋白－大腸桿菌半乳糖酶在已產生免疫力的小黑鼠肌肉中表達，這個單鏈抗體－anti-CTLA4 scFv將來可以在需要重覆肌肉注射轉植基因時用來保護轉植基因的表達。

關鍵字

轉植基因 ； T細胞受器 ； 單鏈抗體 ； 免疫反應 ； 毒殺T細胞相關第四抗原

並列摘要

Objectives: To evaluate whether anti-CTLA4 scFv, a membrane-bound CD152 activator, could protect the expression of a strong immunogen, E. coli beta-galactosidase, during repeated intramuscular injections in immune-competent animals. Materials and Methods: Ten six-to-nine-week old immune competent C57BL/6 mice were divided into two groups. Mice in the first group received four consecutive intramuscular injections of 50 μL endotoxin-free pCBLacZ plasmid in the left anterior tibialis at intervals of one week. The plasmid coded a potent immunogen, E. coli. beta-galactosidase. The other five mice received co-injections of p4F10-eB7, which expressed anti-CTLA4 scFv, and pCBLacZ. All the mice were sacrificed 6 days after the last intramuscular injection. Results: We examined the expression of beta-galactosidase in muscle fibers. The average number of fibers expressing beta-galactosidase was 12.6 in the mice receiving two plasmids compared with 1.4 in their littermates. There were obvious endomyosial
and perimyosial infiltrations of inflammatory cells in both groups. Conclusions: Repeated intramuscular injections of beta-galactosidase can induce strong immune responses in immune-competent animals and cause eradication of transduced muscle fibers by inflammatory cells. Co-administration of anti-CTLA4 scFv can protect the transduced cells. This single chain antibody may be used to prolong the expression of transgene during repeated intramuscular gene delivery.

並列關鍵字

transgene ； T-cell receptor ； single chain antibody ； immune responses ； CTLA4