细胞毒性T淋巴细胞相关抗原4诱导新鲜异体骨移植免疫耐受的实验研究

目的　利用外源性细胞毒性T淋巴细胞相关抗原4 ( cytotoxic T lymphocyte- associated antigen 4immuno globlin,CTL A4 - Ig)阻断T细胞反应的第2信号,诱导新鲜同种异体骨移植免疫耐受。　方法　采用近交系小鼠BAL B/C 6 6只作为骨移植的受体,进行异位肌袋一次及第2次骨移植。一次移植分为3组,每组18只,一组移植C5 7BL/6小鼠骨骼,注射L6 (对照品) ,为AL组;一组移植C5 7BL/6小鼠骨骼,注射CTL A4 - Ig,为AC组;一组移植同系BAL B/C小鼠骨骼,注射PBS缓冲液,为AB组。在第2、4及6周,进行血淋巴细胞亚群分析,血清抗体测定,供体细胞及抗原二次刺激实验及组织学观察。另取12只BAL B/C小鼠,进行第2次移植实验,供体为C5 7BL/6小鼠的骨骼,注射CTL A4 - Ig后2周,分别移植C5 7BL/6 ( BC组)和C3H( BH组)小鼠的骨骼,检测产生免疫耐受的特异性。　结果　AL组与AB组比较,产生了强烈的免疫排斥反应,移植后2、4及6周,CD4 T细胞的增殖明显增加( P<0 .0 5 ) ,血清抗体明显增多( P<0 .0 5 ) ,供体细胞及骨抗原二次刺激的细胞增殖也明显增加( P<0 .0 5 ) ;AC组免疫排斥反应较轻,在CD4 T细胞的增殖、血清抗体及二次刺激的细胞增殖方面均与AB组相似( P>0 .0 5 ) ;组织学观察也显示,异体骨周围的淋巴细胞浸润消失,软骨诱导及新骨形

EXPERIMENTAL STUDY OF IMMUNOLOGICAL TOLERANCE INDUCED BY CYTOTOXIC T LYMPHOCYTE-ASSOCIATED ANTIGEN 4 IMMUNO GLOBLIN IN FRESH BONE ALLOGRAFTS

Objective To study the immunological tolerance induced by blocking the second signal of T cell with extrinsic cytotoxic T lymphocyte associated antigen 4 immuno globlin(CTLA4 Ig). Methods Fifty four BALB C mice, inbred strains, were employed as recipients of bone allografts, using a model of heterotopic muscle pouch. The 54 mice were divided into 3 groups and 18 for each group. The first group, in which the donor was C57BL 6 with intraperitoneal injection of L6(as a control), was named AL group. The second group, also C57BL 6 with injection CTLA4 Ig, was named AC group. The third group, homologous BALB C with injection of PBS buffer solution, was named AB group. The serum antibody, lymphocyte proliferation of the second stimulation by splenic cell and bone supernatant of donor, the analysis of lymphocyte subsets, a regraft experiment and histology were determined 2, 4 and 6 weeks after transplantation. The second transplantation was to regraft C57BL 6(BC group) and C3H(BH group) mice respectively after first 12 mice being transplantated with C57BL 6 and injected with CTLA4 Ig as to detect donor specificity of immunological tolerance. Results Compared with AB group, AL group created more intensive immune rejection: CD4 T cell subsets( P <0.05), the serum antibody( P <0 05) and lymphocyte proliferation of the second stimulation by splenic cell and bone supernatant of donor ( P <0 01 and 0 05) were significantly increased. However, the results of AC group showed that CTLA4 Ig significantly inhibited the immune rejection: CD4 T cell subsets( P > 0 05), the serum antibody ( P >0 05), and lymphocyte proliferation of the second stimulation( P >0 05) were similar to those of AB group. Histological observation of AC group showed that lymphocyte infiltration disappeared, cartilage and new bone formed, and bone marrow cavities emerged. A regraft experiment showed that CD4 T cell subsets ( P <0 05) and lymphocyte proliferation of the second stimulation by splenic cell and bone supernatant of donor ( P <0.05), BC group was significantly lower than those of BH group. So the immunological tolerance induced by CTLA4 Ig was of donor specificity. Conclusion The immunological tolerance induced by CTLA4 Ig was prolonged for 6 weeks. This study provides a brand new path for bone transplantation, which can be helpful to other organ transplantation.