大囊包被异种胰岛免疫保护机理初探

An Investigation of Immunoprotecting Mechanism of Macroencapsulated Pancreatic Islet Xenograft

继实验证明琼脂糖大囊包被异种胰岛移植能减缓排斥反应之后，作者又对琼脂糖大囊包被异种胰岛的免疫保护机理进行了初步探讨。实验分为琼脂糖大囊包被异种（大鼠）胰岛组、未包被异种（大鼠）胰岛组、大囊无胰岛组及同系小鼠胰岛组，每组５个样本。采用淋巴细胞胰岛混合培养（ｍｉｘｅｄｌｙｍｐｈｏｃｙｔｅｉｓｌｅｔｃｕｌｔｕｒｅ，ＭＬＩＣ），测定并计算各组淋巴细胞刺激指数（ｓｔｉｍｕｌａｔｉｎｇｉｎｄｅｘ，ＳＩ）及培养上清液中ＩＬ－２活性。结果：琼脂糖大囊包被异种胰岛组及大囊无胰岛组的ＳＩ和ＩＬ－２活性与同系小鼠胰岛组比较无显著性差异；未包被异种胰岛组的ＳＩ和ＩＬ－２活性分别为１４．２２±３．３８及１７．８±２．１７ＩＵ／ｍｌ，均显著高于同系小鼠胰岛组及琼脂糖大囊包被异种胰岛组。上述结果证明琼脂糖大囊包被技术可明显降低异种胰岛移植物的免疫原性。推测其机理可能与琼脂糖形成的人工膜能将异种胰岛与宿主免疫系统隔离。

Macroencapsulated islet xenografts in agarose are able to prevent rejection. This study was conducted to shed light on the immunoprotecting mechanism of macroencapsulated islet xenografts in agarose. There were four groups ( n =5 in each group):(1) macroencapsulated islet xenografts in agarose; (2) nonencapsulated islet xenografts; (3) agarose macroencapsule without islet; (4) syngenic pancreatic islets. Mixed lymphocyte islet culture (MLIC) was used in the experiment. The results showed that stimulating index (SI) of MLIC and IL 2 level in the macroencapsulated islet xenografts in agarose group were similar to those of syngenic pancreatic islets group. The SI and IL 2 levels of nonencapsulated islet xenograft group were significant higher than those in macroencapsulated islet xenografts in agarose group and syngenic pancreatic islets group. These indicate that macroencapsulation is capable of reducing the immunogenicity of islet xenograft, and it is presumable that macroencapsulated islet xenografts in agarose be not recognized by the recipient's immune system because of being separated by the selectively permeable membrane made with agarose.