Regulation of endothelial VCAM-1 expression in murine cardiac grafts. Roles for TNF and IL4.
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.
Bergese
S
S
Department of Surgery, Ohio State University College of Medicine, Columbus, USA.
Pelletier
R
R
Vallera
D
D
Widmer
M
M
Orosz
C
C
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology*; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000235:genetics; D004730:Endothelium, Vascular / Q000276:immunology*; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D016027:Heart Transplantation / Q000276:immunology*; D007124:Immunoenzyme Techniques; D015847:Interleukin-4 / Q000037:antagonists & inhibitors / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000502:physiology; D019010:Vascular Cell Adhesion Molecule-1
D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D015815:Cell Adhesion Molecules; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D015847:Interleukin-4