日本腦炎長久以來一直是重大的公共衛生問題，其主要傳染途徑是經由蚊子的叮咬，日本腦炎病毒會造成腦膜炎以及中樞神經的病變。腦炎病毒的基因體全長3432bp，在宿主體內轉錄出一條11kD的聚蛋白，並經由病毒的蛋白質及宿主的轉譯後修飾作用，可以產生三個結構性蛋白質以及七個非結構性蛋白質。在結構性蛋白質中，封套蛋白與細胞作用最直接，在許多的研究中也曾指出封套蛋白與宿主的細胞膜產生融合、穿透使得病毒得以釋放遺傳物質進入宿主細胞中。在本研究中，我們將日本腦炎病毒封套蛋白片段選殖出來，經由構築至表現載體後送到細胞當中表達，觀察日本腦炎病毒封套蛋白片段對於細胞的影響。本實驗中使用兩種細胞，其一為日本腦炎病毒的標的細胞，巨噬細胞；其二為上皮細胞COS-7，以西方墨點法來探討在細胞內可能的分子機制。在COS-7細胞株的實驗結果中，發現細胞週期有關的p53蛋白質以及p21蛋白質，隨著轉染封套蛋白時間的增加p21、p53的表現量也隨之增加。接著我們測試與免疫反應有關的NF-κB，NF-κB p105的表現有增加的趨勢，隨著轉染封套蛋白時間的增加，NF-κB p50的表現有降低的趨勢。轉染封套蛋白後與發炎有關的COX-2的表現也呈現下降的趨勢。而mmp2的表現則隨著轉染封套蛋白時間的增加而下降，我們已在COS-7的細胞株建立良好的實驗模式，在巨噬細胞中是否也有相同的結果，有待進一步的實驗來釐清。
Japanese encephalitis virus has been known as a serious issue for a long time that is mainly transmitted via the mosquito and can cause various pathological processing including meningitis and center nerve system disorder. The genome of JEV virus is 3432bp that encodes a polyprotein of 11kD. It consists of three structural proteins and seven non- structural proteins. In the structural protein, the envelope can direct attach with cell surface that pierced cell memberane and release the hereditary material for entering host's cell. In this study, we constructed JEV envelope to expression vector (pEGFP) and transfected COS-7 and RAW264.7 cells for expressing the envelope protein to detect the possible molecular mechanism. In our results, we found p53 and p21 proteins in transfected JEV envelope COS-7 are increased in a time dependent manner. We also found that increased NF-κB, NF-κB p105 in transfected JEV envelope COS-7 is time dependent, but not NF-κB p50. We also found COX-2, the NF-κB down-stream gene that is associated with inflammation, is decreased in a time-dependent manner in JEV-envelope transfected COS-7 cells. Since we have studied the effects of JEV envelope to COS-7 cells, further investigations are required to clarify the precise mechanism in RAW264.7 cells.
