反义HLA-A2 cDNA抑制人成纤维细胞于大鼠脑内移植后的免疫排斥反应

为了探讨人类白细胞抗原(HLA)反义RNA在抑制异种移植免疫排斥反应中的作用,用HLA A2反义cDNA和GDNF共表达的逆转录病毒转导人胚肺成纤维细胞,再移植到Parkinson病大鼠模型纹状体(实验组);同时移植到未感染病毒的人成纤维细胞作对照。移植后每周检测大鼠旋转行为的变化;并于4d、2周、6周灌杀大鼠,进行HLA A、CD4、CD8以及人核糖核蛋白颗粒(RNP)免疫组化染色等以观察宿主的免疫排斥反应和移植物在脑内的存活情况。结果发现:两组间动物的旋转行为变化不明显。实验组HLA A阳性细胞数在移植后的各时间点均明显少于对照组(P<0.05)。移植后4d两组的CD4和CD8阳性细胞数量变化均不明显(P>0.05),CD8细胞较多。2周和6周时实验组的CD4阳性细胞均明显少于对照组(P<0.01),且随时间逐渐下降。2周后实验组的CD8细胞基本消失,而对照组的CD8水平在2周时仍较高, 6周时也可见到。实验组RNP阳性细胞数量在各个时间点都明显多于对照组(P<0.01),到6周时明显下降, 12周时完全消失。反义HLA A2cDNA可以降低异种移植引起的免疫排斥反应程度,延长移植物存活时间,但抑制长期免疫排斥反应方面仍需寻找更好的方法。

ANTISENSE HLA-A2 cDNA SUPPRESSED THE IMMUNE REJECTIONS AGAINST HUMAN FIBROBLASTS XENOGRAFTED IN THE RAT BRAIN

To investigate the effects of antisense HLA-A2 RNA on suppressing immune rejection against the xenografted cells, human embryonic lung fibroblasts transduced with or without the retrovirus harboring antisense HLA-A2 cDNA and GDNF gene were xenografted into the striatum in a rat model of Parkinson's disease. The rotation behavior per week and immunostaining for HLA-A, CD4, CD8, RNP at 4 days, 2 and 6 weeks were determined after grafting of human fibroblasts with or without co-expression of antisense HLA-A2 cDNA and GDNF in order to evaluate immune rejection from host and survival of the xeno-grafted fibroblasts in the brain. The results revealed that rats grafted with GDNF and antisense HLA co-expressing fibroblasts showed no improvement in motor behavior as determined by the rotation test, with a significant decrease in the number of HLA-A2-, CD8- and CD4-immunopositive cells at 2 and 6 weeks after transplantation as compared with those in the control animals ( P <0.01). By contrast, there was a significant increase in the number of RNP immunoreactive fibroblasts in rats with antisense HLA-expressing fibroblasts at the all time-points as compared with control animals ( P <0.01). The RNP cells were reduced significantly at 6 weeks and disappeared completely at 12 weeks after grafting. These results suggested that antisense HLA A2 can reduce immune rejection against the xenotransplanted cells in the brain and prolong survival time of the grafts. However, better ways should be explored to suppress this rejection for a long-term survival of the xenografts in the brain.