Relationship of tissue and cellular interleukin-1 and lipopolysaccharide after endotoxemia and bacteremia.
Distributions of immunoreactive interleukin-1 (IL-1) and lipopolysaccharide (LPS) were studied in the tissues of rats after intravenous injection of purified LPS or live Escherichia coli bacteria. IL-1 staining in the spleen peaked at 4-8 h, colocalized with LPS in marginal zone macrophages, and was undetectable 24 h after injection, whereas LPS staining peaked at 24 h and was detectable for 4 weeks. The tissue IL-1 response was similar for LPS and live bacteria. Thus, tissue IL-1 is down-regulated within hours despite maintenance of LPS in the same cells for weeks. Macrophages in liver and lung had only slight IL-1 staining despite intense staining for LPS. Tissue IL-1 production appears to be differentially regulated after gram-negative bacteremia; LPS cleared by liver and lung macrophages elicit minimal IL-1, whereas there is high local IL-1 production in the marginal zone of the spleen that may increase immune responses to bacterial wall antigens.
Ge
Y
Y
Department of Surgery, Massachusetts General Hospital, Shriners Burns Institute, and Harvard Medical School, Boston, USA.
Ezzell
R M
RM
Clark
B D
BD
Loiselle
P M
PM
Amato
S F
SF
Warren
H S
HS
D000818:Animals; D016470:Bacteremia / Q000276:immunology*; D019446:Endotoxemia / Q000276:immunology*; D007375:Interleukin-1 / Q000032:analysis / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000032:analysis / Q000378:metabolism*; D008099:Liver / Q000276:immunology; D008168:Lung / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013154:Spleen / Q000276:immunology
D007375:Interleukin-1; D008070:Lipopolysaccharides