Ym. Ge et al., RELATIONSHIP OF TISSUE AND CELLULAR INTERLEUKIN-1 AND LIPOPOLYSACCHARIDE AFTER ENDOTOXEMIA AND BACTEREMIA, The Journal of infectious diseases, 176(5), 1997, pp. 1313-1321
Distributions of immunoreactive interleukin-l (IL-1) and lipopolysacch
aride (LPS) were studied in the tissues of rats after intravenous inje
ction 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 st
aining 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 d
ownregulated within hours despite maintenance of LPS in the same cells
for weeks, Macrophages in liver and lung had only slight IL-1 stainin
g despite intense staining for LPS. Tissue IL-1 production appears to
be differentially regulated after gram-negative bacteremia; LPS cleare
d 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.