Mononuclear cell retention in rheumatoid synovial tissue engrafted in severe combined immunodeficient (SCID) mice is up-regulated by tumour necrosis factor-alpha (TNF-alpha) and mediated through intercellular adhesion molecule-1 (ICAM-1).
The aim of this study was to assess regulation of mononuclear cell (MNC) traffic to human synovial tissue by TNF-alpha and IL-1 and the involvement of ICAM-1 in MNC retention in rheumatoid synovial tissue. Human rheumatoid arthritis synovium was engrafted subcutaneously in 6-8 week-old SCID/CB17 mice. Three weeks later, we injected 20 x 10(6) human peripheral blood mononuclear cells (PBMC) previously labelled with 111indium intraperitoneally into mice containing control or cytokine-injected grafts. Total body scintigraphy was performed 72 h postinjection. The graft was removed and immunochemical analysis carried out to assess ICAM-1, vascular cell adhesion molecule-1 (VCAM-1) and E-selectin expression. In some experiments, mice were treated intravenously with 500 micrograms MoAb anti-ICAM-1 (BIRR-1) or an isotype-matched control MoAb before introduction of MNC. TNF-alpha, but not IL-1 alpha, enhanced MNC retention in the rheumatoid synovial graft 72 h post-injection (graft activity 989 +/- 1227 ct/min per 200 pixels or 3.36 +/- 4.16% of initial injected activity versus 411 +/- 157 ct/min per 200 pixels or 1.13 +/- 0.45% in controls; P < 0.03). TNF-alpha enhanced ICAM-1 expression by synovial cells and endothelial cells, whereas VCAM-1 or E-selectin expression was not enhanced on either cell type. After MoAb treatment of ICAM-1, synovial lymphocyte recruitment of TNF-alpha-treated mice decreased significantly to levels below that of control mice (160 +/- 97 ct/min per 200 pixels, 0.54 +/- 0.33%; P < 0.01). Mononuclear cell retention in rheumatoid synovial tissue engrafted into SCID mice was up-regulated by TNF-alpha and blocked by MoAb to ICAM-1. These results suggest that ICAM-1 is involved in mononuclear cell retention in rheumatoid synovium.
Jorgensen
C
C
Service d'Immuno-Rhumatologie, Lapeyromie Hospital, Montpellier, France.
Couret
I
I
Canovas
F
F
Bologna
C
C
Brochier
J
J
Reme
T
T
Lipsky
P
P
Sany
J
J
D000818:Animals; D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D002448:Cell Adhesion / Q000187:drug effects*; D005260:Female; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000494:pharmacology*; D007375:Interleukin-1 / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D051379:Mice; D016513:Mice, SCID; D008875:Middle Aged; D013583:Synovial Membrane / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism* / Q000637:transplantation; D014183:Transplantation, Heterologous / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects*
D007375:Interleukin-1; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1