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英美兩國科學家開發出一種能積累較高含量griffithsin蛋白（GRFT）的轉基因煙草。即便是在皮摩爾級濃度范圍下，這種蛋白也對人體免疫缺陷病毒（HIV）產生明顯的抑制作用。Griffithsin蛋白最初是從Griffithsia紅藻中分離提取的，它能與病毒包膜糖蛋白接合，從而阻止細胞間的HIV病毒傳播。 目前科學家能在460平方米的溫室中利用Nicotana benthamiana生產60克griffithsin蛋白。他們估計這一產量大約能生產100萬份抗HIV制劑。而目前其它抗逆轉錄病毒藥物的規模生產依然代價昂貴。 研究發現這種煙草griffithsin能有效抑制A、B、C三種類型的HIV病毒。A型和C型HIV病毒流行的撒哈拉以南非洲地區及印度次大陸地區迫切需要這種殺菌劑。與其他殺菌劑相比，GFRT還具有一個優點，它不會刺激淋巴細胞增殖。 推薦原始出處： PNAS March 30, 2009, doi: 10.1073/pnas.0901506106 Scaleable manufacture of HIV-1 entry inhibitor griffithsin and validation of its safety and efficacy as a topical microbicide component Barry R. O'Keefea, Fakhrieh Vojdanib, Viviana Buffac, Robin J. Shattockc, David C. Montefiorid, James Bakkee, Jon Mirsalise, Anna-Lisa d'Andreae, Steven D. Humef, Barry Bratcherf, Carrie J. Saucedoa,g, James B. McMahona, Gregory P. Pogueb and Kenneth E. Palmerb,h,1 To prevent sexually transmitted HIV, the most desirable active ingredients of microbicides are antiretrovirals (ARVs) that directly target viral entry and avert infection at mucosal surfaces. However, most promising ARV entry inhibitors are biologicals, which are costly to manufacture and deliver to resource-poor areas where effective microbicides are urgently needed. Here, we report a manufacturing breakthrough for griffithsin (GRFT), one of the most potent HIV entry inhibitors. This red algal protein was produced in multigram quantities after extraction from Nicotiana benthamiana plants transduced with a tobacco mosaic virus vector expressing GRFT. Plant-produced GRFT (GRFT-P) was shown as active against HIV at picomolar concentrations, directly virucidal via binding to HIV envelope glycoproteins, and capable of blocking cell-to-cell HIV transmission. GRFT-P has broad-spectrum activity against HIV clades A, B, and C, with utility as a microbicide component for HIV prevention in established epidemics in sub-Saharan Africa, South Asia, China, and the industrialized West. Cognizant of the imperative that microbicides not induce epithelial damage or inflammatory responses, we also show that GRFT-P is nonirritating and noninflammatory in human cervical explants and in vivo in the rabbit vaginal irritation model. Moreover, GRFT-P is potently active in preventing infection of cervical explants by HIV-1 and has no mitogenic activity on cultured human lymphocytes. (責任編輯：Doctor001) |
