title: ICAM-1 directs migration and localization of interstitial leukocytes in experimental glomerulonephritis.
abstract: Recent studies of rat anti-GBM disease have demonstrated a functional role of the ICAM-1/LFA-1 interaction in the entry of leukocytes into the glomerulus and an association between interstitial ICAM-1 expression, leukocyte infiltration and tubulointerstitial damage. In the current study, we used immunogold ultrastructural techniques to identify ICAM-1/LFA-1 interactions in the initiation of interstitial leukocyte infiltration during the first 24 hours of rat accelerated anti-GBM disease. In normal rats, there was weak constitutive ICAM-1 expression in the interstitium: on the endothelial luminal surface of interstitial capillaries, venules and arterioles, on the entire surface of interstitial fibroblast-like cells and confined to the brush border of proximal tubules. As early as 1.5 hours after injection of anti-GBM serum, there was a marked increase in the intensity of ICAM-1 expression, most notably on capillary endothelium, fibroblast-like cells and brush borders of proximal tubules, particularly in the periglomerular/perihilar areas. Mononuclear leukocytes exhibiting strong surface LFA-1 (CD11a and CD18) expression were seen adherent to the endothelium of interstitial capillaries, with ICAM-1 and LFA-1 antigens present at sites of contact. In addition, mononuclear cells migrating into the interstitium showed areas of close apposition to interstitial fibroblast-like cells, and here ICAM-1 and LFA-1 expression were also prominent at the sites of contact. This is the first study to demonstrate sites of ICAM-1/LFA-1 interaction in mononuclear cell migration and localization in glomerulonephritis. The results suggest that up-regulation of periglomerular/peritubular capillary ICAM-1 expression is important for mononuclear cell entry into the interstitium, while interaction with fibroblast-like cells may facilitate movement and subsequent focal accumulation of mononuclear cells at sites within the interstitium.
authors.affiliation: Department of Anatomy, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: P A
authors.initials: PA
authors.lastname: Hill
authors.forename: H Y
authors.initials: HY
authors.lastname: Lan
authors.forename: D J
authors.initials: DJ
authors.lastname: Nikolic-Paterson
authors.forename: R C
authors.initials: RC
authors.lastname: Atkins
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D001485:Basement Membrane / Q000276:immunology; D015815:Cell Adhesion Molecules / Q000502:physiology* / Q000648:ultrastructure; D002465:Cell Movement / Q000502:physiology; D005921:Glomerulonephritis / Q000276:immunology / Q000473:pathology* / Q000503:physiopathology*; D007150:Immunohistochemistry; D007678:Kidney Glomerulus / Q000276:immunology; D007962:Leukocytes / Q000502:physiology*; D008297:Male; D016253:Microscopy, Immunoelectron; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values
chemical_list: D000906:Antibodies; D015815:Cell Adhesion Molecules