Characterization of rat lung ICAM-1.
OBJECTIVE
We expressed soluble rat ICAM-1, generated a polyclonal anti-ICAM-1 antibody, and studied ICAM-1 upregulation in lung inflammatory conditions. Bacterial and baculovirus expression systems were employed.


METHODS
250 g adult, male Long Evans rats were used. For in vitro studies, rat pulmonary artery endothelial cells (RPAEC), rat alveolar macrophages and aortic rings were stimulated (as described below) and evaluated for ICAM-1 expression.


METHODS
RPAEC and macrophages were stimulated with lipopolysaccharide (LPS) and recombinant murine tumour necrosis factor alpha (TNFalpha). In vivo immunoglobulin G (IgG) immune complex-induced lung injury was employed.


METHODS
Enzyme-linked immunoassay (ELISA) Western and Northern blot analyses and immunohistochemical evaluations were performed. All experiments were done at least in duplicate. Data were analyzed by two-tailed Student's t-test.


RESULTS
ICAM-1 expression of RPAEC was time- and dose-dependent, peaking at 6h after LPS-stimulation. LPS and TNFalpha each enhanced ICAM-1 expression on alveolar macrophages (reaching a maximum at 2 h). In IgG immune complex-induced lung injury, ICAM-1 mRNA isolated from whole lung peaked at 4 h, while lung ICAM- I protein peaked at 6 h.


CONCLUSIONS
Quantitation of ICAM-1 expression in vitro and in vivo suggests that ICAM-1 plays a central role in two lung inflammatory models. Furthermore, lung ICAM-1 upregulation involves at least two cell types: vascular endothelial cells and alveolar macrophages.
Beck-Schimmer
B
B
Department of Pathology, University of Michigan Medical School, Ann Arbor 48109-0602, USA.
Schimmer
R C
RC
Schmal
H
H
Flory
C M
CM
Friedl
H P
HP
Pasch
T
T
Ward
P A
PA
D000818:Animals; D001419:Bacteria / Q000378:metabolism; D016367:Baculoviridae / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D002460:Cell Line; D004730:Endothelium, Vascular / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D007074:Immunoglobulin G / Q000276:immunology; D007150:Immunohistochemistry; D007313:Insecta / Q000166:cytology / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis / Q000737:chemistry*; D008168:Lung / Q000737:chemistry* / Q000378:metabolism; D016676:Macrophages, Alveolar / Q000378:metabolism; D008297:Male; D011014:Pneumonia / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction
D007074:Immunoglobulin G; D011994:Recombinant Proteins; D018799:Intercellular Adhesion Molecule-1