MHC II类抗原的诱导性表达和同种异体软骨细胞移植的免疫排斥

本研究将不同年龄香猪的软骨细胞和可注射性材料复合物Pluronic混合在一起 ,以 5 0× 10 6/ml浓度接种到版纳猪的腹部皮下 ,在第 1、 2、 4周取材作组织学检查 ,并进行软骨细胞表面标志的分析和测定淋巴细胞软骨细胞混合反应(MLChR )的强度。结果显示 :猪的软骨细胞仅表达MHCI类分子 ,分别来自胎猪、幼猪和成年猪的软骨细胞刺激MLChR的能力无显著差别 ,均表现抗原性较弱。经IFN γ诱导后 ,软骨细胞表达MHCII类抗原 ,能明显地刺激淋巴细胞增殖。免疫病理学检测发现 ,在组织化的软骨中 ,第 1周出现大量淋巴细胞浸润 ,第 4周组织化软骨消失。上述结果提示 ,体内同种异体软骨细胞被迅速排异 ,可能与MHCII类抗原诱导性表达有关

Inducible Expression of MHC Class II Antigens on Chondrocytes and Their Rejection in Allogeneic Grafting

To study the allo reactions in transplantation with the tissue engineered chondrocytes taken from different developmental stages of a Chinese minipig strain of Xiang zhu,the chondrocytes were mixed with an injectable complex Pluronic and injected into subcutaneous tissues of abdomen of another minipig strain of Banna minipig at the dosages of 50×10 6/ml.The phenotypes of the chondrocytes were assayed by FACS and their antigenicity was determined in a mixed lymphocyte chondrocyte mixed reaction(MLChR)system,in which the lymphocytes of the Banna strain and the chondrocytes of the Xiang zhu strain were functioned as responding and stimulating cells respectively.The chondrocytes which were detected to express the MHC class I molecules constitutively,were not able to initiate a significant allo response of lymphocytes,and there were no obvious differences among the chondrocytes with different ages in terms of antigenicity.Allo responses could be evolved,however,when the chondrocytes began to express the MHC class II antigens after the treatment with swine IFN γ.The biopsies taken every weeks after transplantations showed that in the first week there were lymphocyte infiltrations in the tissue engineered cartilage and that the allogeneic cartilages began to be absorbed in the fourth week.The fact that the tissue engineered cartilages were rejected promptly even though the antigenicity of the original ones was not so strong,suggests that the inducible expression of the MHC class II molecules by some means during the allo grafting(such as by treatment with IFN γ)might be a critical factor attributable for the rejection reactions.