Ahmed K R, Guo T B, Gaal K K
Department of Medicine, Harbor-UCLA Medical Center, Torrance, California 90509, USA.
Transplantation. 1997 Apr 15;63(7):951-7. doi: 10.1097/00007890-199704150-00008.
Perforin and Fas are the two main pathways by which cytotoxic T lymphocytes (CTLs) mediate target cell lysis in vitro. The perforin pathway is predominantly used by CD8+ cells, which comprise the majority of CTLs. The Fas pathway has been demonstrated to be the principal cytolytic mechanism in CD4+ CTLs. CTLs have been shown to play an important role in allograft rejection. In this study, we examined the relevance of perforin and Fas to allograft rejection by transplanting pancreatic islets from fully allogeneic C3H/HeJ (C3H) or Fas-deficient C3H/lpr donors into perforin-deficient (P0) mice or controls with intact perforin genes (P2).
P0 or P2 mice that were rendered diabetic with streptozotocin at 300 mg/kg i.p. received approximately 350 islets obtained from C3H or C3H/lpr donors by in situ collagenase digestion and Ficoll density centrifugation of the pancreas. Four groups of animals were studied: C3H to P2 (group 1), C3H to P0 (group 2), lpr to P0 (group 3), and syngeneic P2 to P2 (group 4). Graft survival monitored by blood sugar levels was compared among the groups. At the time of rejection (blood sugar >300 mg/100 ml), grafts were harvested and analyzed by histopathology, immunocytochemistry, and reverse transcriptase-polymerase chain reaction. Primary splenic T cells of the recipients, harvested at the time of rejection, were tested for cytotoxicity against 51Cr-labeled donor cells.
The mean graft survival for groups 1, 2, and 3 was 10.2+/-1.4, 12.2+/-6.0, and 13.2+/-0.8 days, respectively. Syngeneic grafts survived indefinitely. Rejecting grafts from all groups (1, 2, and 3) showed an intense infiltration by both CD4+ and CD8+ cells and complete islet destruction. Reverse transcriptase-polymerase chain reaction revealed granzyme B in rejecting grafts from all three groups.
Perforin and Fas pathways alone or in combination are not required for islet rejection, suggesting that these pathways may not play a crucial role in allograft rejection.
穿孔素和Fas是细胞毒性T淋巴细胞（CTLs）在体外介导靶细胞裂解的两条主要途径。穿孔素途径主要由占CTLs大多数的CD8 +细胞使用。Fas途径已被证明是CD4 + CTLs中的主要溶细胞机制。CTLs已被证明在同种异体移植排斥中起重要作用。在本研究中，我们通过将完全同种异体的C3H/HeJ（C3H）或Fas缺陷的C3H/lpr供体的胰岛移植到穿孔素缺陷（P0）小鼠或具有完整穿孔素基因的对照（P2）小鼠中，研究了穿孔素和Fas与同种异体移植排斥的相关性。
通过腹腔注射300mg/kg链脲佐菌素使P0或P2小鼠患糖尿病，通过原位胶原酶消化胰腺并经Ficoll密度离心从C3H或C3H/lpr供体获得约350个胰岛。研究了四组动物：C3H至P2（第1组），C3H至P0（第2组），lpr至P0（第3组），以及同基因P2至P2（第4组）。比较各组通过血糖水平监测的移植物存活情况。在排斥时（血糖>300mg/100ml），收获移植物并通过组织病理学、免疫细胞化学和逆转录聚合酶链反应进行分析。在排斥时收获的受体的原代脾T细胞，检测其对51Cr标记的供体细胞的细胞毒性。
第1、2和3组的平均移植物存活时间分别为10.2±1.4、12.2±6.0和13.2±0.8天。同基因移植物无限期存活。所有组（1、2和3）的排斥移植物均显示CD4 +和CD8 +细胞强烈浸润以及胰岛完全破坏。逆转录聚合酶链反应显示所有三组排斥移植物中均有颗粒酶B。
胰岛排斥不需要单独或联合穿孔素和Fas途径，表明这些途径可能在同种异体移植排斥中不发挥关键作用。
