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英美两国科学家开发出一种能积累较高含量griffithsin蛋白（GRFT）的转基因烟草。即便是在皮摩尔级浓度范围下，这种蛋白也对人体免疫缺陷病毒（HIV）产生明显的抑制作用。Griffithsin蛋白最初是从Griffithsia红藻中分离提取的，它能与病毒包膜糖蛋白接合，从而阻止细胞间的HIV病毒传播。 目前科学家能在460平方米的温室中利用Nicotana benthamiana生产60克griffithsin蛋白。他们估计这一产量大约能生产100万份抗HIV制剂。而目前其它抗逆转录病毒药物的规模生产依然代价昂贵。 研究发现这种烟草griffithsin能有效抑制A、B、C三种类型的HIV病毒。A型和C型HIV病毒流行的撒哈拉以南非洲地区及印度次大陆地区迫切需要这种杀菌剂。与其他杀菌剂相比，GFRT还具有一个优点，它不会刺激淋巴细胞增殖。 推荐原始出处： 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. (责任编辑：Doctor001) |
