Bergese S, Pelletier R, Vallera D, Widmer M, Orosz C
Department of Surgery, Ohio State University College of Medicine, Columbus, USA.
Am J Pathol. 1995 Apr;146(4):989-98.
The in vivo mechanisms of vascular endothelial activation and VCAM-1 expression were studied in murine heterotopic cardiac grafts. Preliminary studies demonstrated that cardiac allograft endothelia develop reactivity with MECA-32 monoclonal antibody (MAb) and M/K-2 (anti-VCAM-1) MAb within 3 days of transplantation, whereas cardiac isografts develop MECA-32 reactivity but no M/K-2 reactivity. Additional studies demonstrated that a single treatment of cardiac isograft recipients with the anti-CD3 MAb 145-2C11 induces VCAM-1 expression on isograft microvascular endothelia within 24 hours. We have used this experimental system to identify the cytokines responsible for expression of VCAM-1 and MECA-32 MAb reactivity on graft vascular endothelia. We report that the expression of VCAM-1 on isograft endothelia that was induced with anti-CD3 MAb was blocked by simultaneous treatment with either pentoxifylline, soluble tumor necrosis factor (TNF) receptor (TNFR-Fc), anti-IL4 MAb, or soluble IL4R, but not by anti-IFN-gamma MAb. Alternatively, a similar pattern of isograft endothelial VCAM-1 expression was stimulated in the absence of anti-CD3 MAbs with a single injection of human recombinant TNF-alpha, or with recombinant murine IL4 provided as IL4/anti-IL4 MAb complexes. In addition, the IL4-induced VCAM-1 expression was completely blocked by a single intravenous treatment of the isograft recipients with TNFR:Fc. This suggests that high concentrations of TNF-alpha can stimulate endothelial VCAM-1 expression, but these concentrations are apparently not achieved in cardiac isografts. In the absence of an inducing agent such as anti-CD3 MAb, the stimulation of VCAM-1 expression with exogenous IL4 may reflect functional interaction between endogenous TNF and exogenous IL4, as suggested by the blocking experiments with TNFR:Fc. Although cardiac isograft endothelia normally develop reactivity with MECA-32 MAb within 3 days of transplantation, treatment of cardiac isograft recipients with anti-CD3 MAb accelerated MECA-32 reactivity to within 24 hours of transplantation. This accelerated expression can be experimentally manipulated in the same way as M/K-2 reactivity, suggesting that similar mechanisms may control the development of these two inflammatory endothelial phenotypical markers, despite their differential expression in cardiac isografts and allografts.
在小鼠异位心脏移植模型中研究了血管内皮激活和VCAM - 1表达的体内机制。初步研究表明，心脏同种异体移植内皮细胞在移植后3天内就会与MECA - 32单克隆抗体（MAb）和M/K - 2（抗VCAM - 1）MAb发生反应，而心脏同基因移植内皮细胞会产生MECA - 32反应，但不产生M/K - 2反应。进一步研究表明，用抗CD3 MAb 145 - 2C11单次处理心脏同基因移植受体，可在24小时内诱导同基因移植微血管内皮细胞表达VCAM - 1。我们利用这个实验系统来确定负责移植血管内皮细胞上VCAM - 1表达和MECA - 32 MAb反应性的细胞因子。我们报告，抗CD3 MAb诱导的同基因移植内皮细胞上VCAM - 1的表达可被同时用己酮可可碱、可溶性肿瘤坏死因子（TNF）受体（TNFR - Fc）、抗IL4 MAb或可溶性IL4R处理所阻断，但不能被抗IFN - γ MAb阻断。另外，在没有抗CD3 MAbs的情况下，单次注射人重组TNF - α或作为IL4/抗IL4 MAb复合物提供的重组鼠IL4，可刺激同基因移植内皮细胞VCAM - 1表达出现类似模式。此外，同基因移植受体单次静脉注射TNFR:Fc可完全阻断IL4诱导的VCAM - 1表达。这表明高浓度的TNF - α可刺激内皮细胞VCAM - 1表达，但在心脏同基因移植中显然未达到这些浓度。在没有诸如抗CD3 MAb这样的诱导剂的情况下，外源性IL4刺激VCAM - 1表达可能反映了内源性TNF与外源性IL4之间的功能相互作用，正如用TNFR:Fc进行的阻断实验所表明的那样。尽管心脏同基因移植内皮细胞通常在移植后3天内就会与MECA - 32 MAb发生反应，但用抗CD3 MAb处理心脏同基因移植受体可将MECA - 32反应性加速至移植后24小时内。这种加速表达可以与M/K - 2反应性相同的方式进行实验调控，这表明尽管这两种炎症内皮表型标志物在心脏同基因移植和同种异体移植中的表达存在差异，但可能由相似的机制控制它们的产生。
