Handa J T, Houston L L, Jaffe G J
Duke Eye Center, Durham, North Carolina.
Invest Ophthalmol Vis Sci. 1993 Nov;34(12):3419-28.
To determine the effect of a rabbit transferrin conjugated to recombinant ricin A chain (Tfr-rRA) and the carboxylic ionophore monensin on proliferating and density-arrested human retinal pigment epithelial cells and rabbit dermal fibroblasts.
Cells were seeded on 24-well plates at 20,000 cells/cm2 and exposed to Tfr-rRA (0.1-10,000 ng/ml) with or without monensin (0.01 microM), and with or without human transferrin (65.7 mg/l) for 5 minutes to 7 days. Cells were studied morphologically and counted at 1, 2, 4, and 7 days.
Tfr-rRA (10-10,000 ng/ml) killed proliferating human retinal pigment epithelial cells and rabbit dermal fibroblasts in a dose-dependent manner (p < or = 0.01) up to a maximum of 86% and 93%, respectively. In contrast, Tfr-rRA had minimal effect on density-arrested human retinal pigment epithelial cells and rabbit dermal fibroblasts. The cytotoxicity of Tfr-rRA was inhibited by the addition of human transferrin (65.7 mg/l), an effect that was partially overcome by longer treatment with Tfr-rRA. Monensin (0.01 microM) increased the cytotoxicity of Tfr-rRA by 4.8-fold over Tfr-rRA alone, shortened the onset of cell kill with Tfr-rRA from 48 to 24 hours (P = 0.04), and partially reversed the neutralizing effect of human transferrin.
The results indicate that Tfr-rRA effectively inhibited the proliferation of human retinal pigment epithelial cells and rabbit dermal fibroblasts in vitro. The inhibitory effect could be modified by the addition of human transferrin or monensin. Thus, this ricin A chain conjugate may interrupt the proliferation of cells necessary in the pathogenesis of proliferative vitreoretinopathy.
确定与重组蓖麻毒素A链结合的兔转铁蛋白（Tfr-rRA）和羧酸离子载体莫能菌素对增殖的和密度抑制的人视网膜色素上皮细胞及兔真皮成纤维细胞的作用。
将细胞以20,000个细胞/平方厘米的密度接种于24孔板，分别用或不用莫能菌素（0.01微摩尔）、用或不用人转铁蛋白（65.7毫克/升），再暴露于Tfr-rRA（0.1 - 10,000纳克/毫升）中5分钟至7天。在第1、2、4和7天对细胞进行形态学研究和计数。
Tfr-rRA（10 - 10,000纳克/毫升）以剂量依赖性方式杀死增殖的人视网膜色素上皮细胞和兔真皮成纤维细胞（p≤0.01），最高分别可达86%和93%。相比之下，Tfr-rRA对密度抑制的人视网膜色素上皮细胞和兔真皮成纤维细胞影响极小。添加人转铁蛋白（65.7毫克/升）可抑制Tfr-rRA的细胞毒性，而延长Tfr-rRA处理时间可部分克服这种作用。莫能菌素（0.01微摩尔）使Tfr-rRA的细胞毒性比单独使用Tfr-rRA时增加4.8倍，将Tfr-rRA导致细胞死亡的起始时间从48小时缩短至24小时（P = 0.04），并部分逆转了人转铁蛋白的中和作用。
结果表明Tfr-rRA在体外可有效抑制人视网膜色素上皮细胞和兔真皮成纤维细胞的增殖。添加人转铁蛋白或莫能菌素可改变这种抑制作用。因此，这种蓖麻毒素A链偶联物可能会阻断增殖性玻璃体视网膜病变发病机制中所需细胞的增殖。
