大溪地等鞭金藻抗B型肝炎病毒野生型及Lamivudine抗藥性突變株作用之探討

Studies of Anti-HBV Effects of Isochrysis aff. galbana on Wild-type HBV and Lamivudine-Resistant Mutant HBV

B 型肝炎是國人常見的肝疾，會引起急性及慢性肝炎，慢性肝炎患者長期染病，極易轉為猛暴性肝炎、肝硬化及肝癌。B 型肝炎目前雖然有疫苗，但是國內仍有約300 萬病毒帶原者需要治療。目前臨床上使用之治療藥物，以lamivudine（即3TC），有非常肯定的療效，可惜仍然有抗藥性的問題。因長期服用lamivudine 藥物的B 型肝炎患者會因產生抗藥性而使病毒量嚴重升高，lamivudine 抗藥性突變株為B 型肝炎病毒聚合酶基因的YMDD 位置產生單一點突變成為YVDD，因此全世界許多國家仍在努力研究中，對此是否能另外從海洋中找尋出抗B 型肝炎病毒藥物為重點。本論文以體外細胞培養模式，利用酵素連結免疫吸附分析法，測定大溪地等鞭金藻甲醇萃取物對人類B 型肝炎病毒野生型及lamivudine 抗藥性突變株於病毒表面抗原及e 抗原之作用。結果顯示大溪地等鞭金藻甲醇萃取物在lamivudine 抗藥性突變株（M33 細胞株）之表面抗原具有極顯著的抑制作用，但是在野生型（MS-G2 細胞株）之表面抗原不具抑制作用。而兩細胞株在e 抗原的表現上均無抑制作用。期望有助於臨床抗病毒藥物之開發。

Viral Hepatitis B is the major cause of acute and chronic hepatitis. Chronic infection has been known to be the precursor for cirrhosis and hepatocellular carcinoma (HCC). Despite the availability of an effective preventive vaccine for HBV in recent years, there are still 300 million existing chronic HBV carriers that urgently need therapy. Recently, lamivudine (also called 3TC), a cytosine nucleoside analogue, has been shown to be very effective in therapeutic treatment of hepatitis B. However, after long-term administration of lamivudine, drug-resistant HBV mutations can occur. The drug-resistant mutations are believed to be due to site-directed mutagenesis on YMDD motif of the wild-type HBV DNA polymerase gene. To address the issue, many research efforts worldwide are now focused on identifying marine-based drugs with effective anti-HBV effects while free from the above-mentioned drug-resistant mutations. In this paper, we use an in vitro cell culture system and the ELISA method to assay the inhibition of surface and e antigen in Isochrysis aff. galbana on wild-type HBV(MS-G2 cell line) and lamivudine-Resistant Mutant HBV(M33 cell line). Our results showed that the methanol extract of Isochrysis aff. galbana exhibits very significant inhibition on the expression of the surface antigen from the lamivudine-Resistant Mutant HBV. However, no significant inhibition on the expression of surface antigen from wild-type HBV was found. In addition, the methanol extract of Isochrysis aff. galbana exhibits no effect on the expression of e antigen from either lamivudine-Resistant Mutant HBV or wild-type HBV.