Yu S, Nakafusa Y, Flye M W
Department of Surgery, Washington University School of Medicine, St. Louis , Missouri 63110, USA.
Transplantation. 1997 Dec 27;64(12):1684-8. doi: 10.1097/00007890-199712270-00009.
Normally, a Buffalo (BUF) recipient (RT1b) rejects a heterotopically transplanted Lewis (LEW) heart (RT1l) drained into the portal vein (PV) within 14 days. However, the addition of PV administration of 25x10(6) ultraviolet B (UVB)-treated LEW spleen cells (SC) to BUF recipients 7 days before cardiac transplantation results in 70% long-term allograft survival.
In this study, we used gadolinium chloride (GdCl3) (7 mg/kg/day) to selectively block the phagocytosis of recipient hepatic Kupffer cells before PV injection of UVB-treated donor SC to examine the mechanism of tolerance induction, as measured by in vitro analysis of mixed lymphocyte culture (MLC), T cell cytotoxicity, T helper cell precursors (pTH), and cytotoxic T cell precursors (pCTL) by limiting dilution analysis.
A BUF recipient that received untreated or gamma-irradiated LEW SC intraportally reacted to in vitro stimulation by LEW alloantigen with increased MLC proliferation, T cell cytotoxicity, pTH and pCTL frequencies, and interleukin-2 production. In contrast, SC from BUF that received UVB-treated LEW SC were hyporesponsive on MLC stimulation by donor LEW alloantigen and exhibited markedly reduced cytotoxicity, pTH and pCTL frequency, and interleukin-2 production. However, normal in vitro responsiveness resulted with stimulation by third-party Brown-Norway (RT1n) SC, thus indicating that the systemic hyporesponsiveness was specific for the UVB donor alloantigen given PV. On the other hand, GdCl3 given by intravenous injection daily for 3 days before PV alloantigen blocked the induction of in vitro hyporesponsiveness.
Therefore, prevention of alloantigen sequestration by GdCl3 inhibition of hepatic Kupffer cell phagocytosis was pivotal in preventing the development of portal venous tolerance.
正常情况下，水牛（BUF）受体（RT1b）会在14天内排斥异位移植至门静脉（PV）的Lewis（LEW）心脏（RT1l）。然而，在心脏移植前7天给BUF受体经门静脉注射25×10⁶个经紫外线B（UVB）处理的LEW脾细胞（SC），可使70%的移植物长期存活。
在本研究中，我们在经门静脉注射经UVB处理的供体SC前，使用氯化钆（GdCl₃）（7毫克/千克/天）选择性阻断受体肝库普弗细胞的吞噬作用，以通过混合淋巴细胞培养（MLC）的体外分析、T细胞细胞毒性、辅助性T细胞前体（pTH）以及通过有限稀释分析的细胞毒性T细胞前体（pCTL）来检测耐受诱导机制。
经门静脉接受未处理或经γ射线照射的LEW SC的BUF受体，对LEW同种异体抗原的体外刺激产生反应，表现为MLC增殖增加、T细胞细胞毒性、pTH和pCTL频率以及白细胞介素-2产生增加。相比之下，接受经UVB处理的LEW SC的BUF来源的SC，在受到供体LEW同种异体抗原的MLC刺激时反应低下，且细胞毒性、pTH和pCTL频率以及白细胞介素-2产生明显降低。然而，受到第三方Brown-Norway（RT1n）SC刺激时，体外反应正常，这表明全身反应低下是针对经门静脉给予的UVB供体同种异体抗原的特异性反应。另一方面，在经门静脉给予同种异体抗原前3天每天静脉注射GdCl₃可阻断体外反应低下的诱导。
因此，通过GdCl₃抑制肝库普弗细胞吞噬作用来防止同种异体抗原的隔离，对于预防门静脉耐受的形成至关重要。
