Study of Graft Infiltrating Cells in Rat Small Bowel transplantation

• Project/Area Number: 07671951
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 小児外科
• Research Institution: Osaka University
• Principal Investigator: AZUMA Tatsuo Osaka University, Medical School, Assistant Professor, 医学部, 助手 (90263285)
• Co-Investigator(Kenkyū-buntansha): OKADA Akira Osaka University, Medical School, Professor, 医学部, 教授 (40028569)
• Project Period (FY): 1995 – 1996
• Project Status: Completed (Fiscal Year 1996)
• Budget Amount: ¥1,700,000 (Direct Cost: ¥1,700,000); Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000); Fiscal Year 1995: ¥1,300,000 (Direct Cost: ¥1,300,000)
• Keywords: small bowel transplantation / graft infiltranting cell / lamina propria / flow cytometry / liver / FK506 / 拒絶反応 / 粘膜固有層細胞 / CD8αβ^+細胞 / NK細胞

Research Abstract

The aim of this study is to investigate the graft infiltrating cells (GIC) in laminapropria (LP). The origin and phenotype of GIC were studied by flow cytometry analysis after isolation.
Allogeneic heterotopic jejunal transplantations (15 cm in length) were performed from DA (RT1<@D1a@>D1) to PVG (RT1<@D1c@>D1). In this combination, DA small bowel allografts in PVG recipients are rejected on day 7 (]SY.+-[) 2 but a spontaneously tolerated DA liver allograft in PVG induces tolerance of DA intestinal graft performed 17days later. The recipients were divided into 3 groups : Group 1 (NTG) : no treatment (n=5), Group 2 (L/SBG) : Liver/small bowel transplantation (n=5), Group 3 (FKG) : 0.3mg/Kg/day of FK506 i.m for 14 days (n=6). After SBT,grafts were takenon day 5 in Group 1,2 and on day 14 in Group 3 respectively.
(1) The proportion of recipient origin cells in FKG was not increased compared to NTG,while that in L/SBG was significantly increased (NTG : 59.0 (]SY.+-[) 7.2%, L/SBG : 95.3 (]SY. +-[) 5.4%, FKG : 57.2 (]SY.+-[) 10.5%).
(2) In NTG and L/SBG,recipient origin GIC contained a higher propotion of T cells (NTG=TcR alpha beta<@D1+@>D1 : 61.5 (]SY.+-[) 7.4%, CD4<@D1+@>D1 : 38.2 (]SY.+-[) 8.6%, CD8 alpha<@D1+@>D1 : 42.9 (]SY.+-[) 3.5%, NKR-P1<@D1+@>D1 : 27.7 (]SY.+-[) 8.2%, L/SBG=TcR alpha beta<@D1+@>D1 : 79.9 (]SY.+-[) 6.4%, CD4<@D1+@>D1 : 38.0 (]SY.+-[) 6.6%, CD8 alpha<@D1+@>D1 : 44.6 (]SY.+-[) 12.3%, NKR-P1<@D1+@>D1 : 7.5 (]SY.+-[) 3.9%). In contrast, the ratio of CD8 alpha<@D1+@>D1 (CD8 alpha alpha/CD8 alpha beta) and NK cells was signifcantly decreased in FKG (TcR alpha beta<@D1+@>D1 : 42.2 (]SY.+-[) 19.6%, CD4<@D1+@>D1 : 39.4 (]SY.+-[) 13.0%, CD8 alpha<@D1+@>D1 : 11.7 (]SY.+-[) 6.8, NKR-P1<@D1+@>D1 : 8.2 (]SY.+-[) 3.1%).
(3) The expression of CD25 (IL-2R) in FKG was not reduced compared to NTG (NTG=TcR alpha beta<@D1+@>D1 : 41.3 (]SY.+-[) 10.4%, CD4<@D1+@>D1 : 55.2 (]SY.+-[) 12.2%, CD8 alpha<@D1+@>D1 : 28.2 (]SY.+-[) 13.9%, NKR-P1<@D1+@>D1 : 16.2 (]SY.+-[) 8.4%, FKG=TcR alpha beta<@D1+@>D1 : 41.8 (]SY.+-[) 11.5%, CD4<@D1+@>D1 : 38.2 (]SY.+-[) 16.7%, CD8 alpha<@D1+@>D1 : 24.2 (]SY.+-[) 9.8%, NKR-P1<@D1+@>D1 : 29.7 (]SY.+-[) 12.4%), while the expression of CD25 in L/SBG was significantly decreased among all subsets (TcR alpha beta<@D1+@>D1 : 17.0 (]SY.+-[) 9.2%, CD4<@D1+@>D1 : 28.2 (]SY.+-[) 11.0%, CD8 alpha<@D1+@>D1 : 4.6 (]SY.+-[) 4.4%, NKR-P1<@D1+@>D1 : 1.0 (]SY.+-[) 2.0%).
This study shows that liver-induced tolerance of intestinal grafts is associated with anergic state of recipient T cells by down regulation of CD25 on T cells on recipient origin. In contrast, low dose of FK506 does not affect the expression of CD25 of recipient origin cells and immunosuppression by FK506 is associated with reduced proporion of CD8 alpha^+ (CD8 alpha alpha^+/CD8 alpha beta^+, especially CD8 alpha beta^+) and NK cells among recipient origin cells in LP.