Differential effects of interleukin-4 and interleukin-10 on nitric oxide production by murine macrophages.
OBJECTIVE
To study the effect of interleukin (IL)-4 and IL-10 on nitric oxide (NO) production by macrophages.


METHODS
Elicited or resident peritoneal macrophages (PMO) and a macrophage cell line Raw264.7 were primed by IL-4 or IL-10 for 6 hours, and were further incubated in the presence of interferon (IFN)-gamma and/or lipopolysaccharide (LPS) for 48 hours. NO2- accumulation in the supernatant of cultured cells was used as an indicator of NO production and was determined by the standard Griess reaction adapted for microplates. The amount of tumor necrosis factor (TNF)-alpha in the culture supernatants was determined with a commercially available ELISA kit. The absorbance was measured at 450 nm with a microplate photometer.


RESULTS
IL-4 inhibited NO production by murine macrophages of different sources and the macrophage cell line Raw264.7. In contrast, different macrophage populations showed differential responses to IL-10. After stimulation with LPS or IFN-gamma, IL-10 suppressed NO production by elicited PMO but enhanced NO production by resident PMO or by Raw264.7. Both IL-4 and IL-10 inhibited the production of TNF-alpha, which has been shown to play a crucial role in NO production. In the presence or the absence of blocking antibody to TNF-alpha, IL-10 always enhanced NO production by resident PMO. This result suggests that the inhibition of TNF-alpha production and the enhancement of NO production by resident PMO stimulated with IL-10 are independent, coexisting events.


CONCLUSIONS
Factors other than TNF-alpha have been suspected to influence NO production by macrophages, and this study indicates that IL-10 may be a candidate cytokine for resident PMO.
Nemoto
Y
Y
First Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Otsuka
T
T
Niiro
H
H
Izuhara
K
K
Yamaoka
K
K
Nakashima
H
H
Niho
Y
Y
D000818:Animals; D002478:Cells, Cultured; D005260:Female; D007371:Interferon-gamma / Q000494:pharmacology; D016753:Interleukin-10 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009569:Nitric Oxide / Q000096:biosynthesis*; D011994:Recombinant Proteins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D015847:Interleukin-4; D009569:Nitric Oxide; D007371:Interferon-gamma