Suppressive effects of serum on the LPS-induced production of nitric oxide and TNF-alpha by a macrophage-like cell line, WEHI-3, are dependent on the structure of polysaccharide chains in LPS.
The effect of serum on LPS-induced activation of a murine macrophage-like cell line, WEHI-3, was examined. Foetal calf serum strongly inhibited the production of nitric oxide (NO) and TNF-alpha by LPS-stimulated WEHI-3 cells, while it enhanced the production of both by other macrophage-like cell lines, J774.1 and BAM3, on treatment with LPS. This suppressive effect of serum on WEHI-3 cells was most remarkable when the cells were stimulated with rough-chemotype LPS, Ra LPS, Rc LPS and Rd2 LPS. Foetal calf serum also inhibited TNF-alpha production by the same cells stimulated with high concentrations of smooth-form LPS (S LPS; > 1000 ng/mL). Serum-mediated suppression was also observed for expression of the TNF-alpha gene in Rc LPS-stimulated WEHI-3 cells. This suppressive effect of FCS was most remarkable during the 1-2 h before the addition of LPS, but it was not observed when FCS was added at 1 h after the addition of LPS, suggesting dependence on the time of FCS addition to LPS-stimulated cells. No significant difference was observed in the expression of CD14 on WEHI-3 cells cultured in the presence and absence of serum, suggesting that CD14 is not involved in the serum-mediated suppression of these LPS-responses. On the contrary, FCS showed enhancing effects on the production of NO and TNF-alpha by WEHI-3 cells stimulated with low concentrations (< 100 ng/mL) of S LPS and rough mutant Salmonella minnesota Re LPS. These results suggest that the ability of FCS to suppress LPS-induced activation of WEHI-3 cells in mainly dependent on the structure of polysaccharide chains and also on the concentration of LPS employed.
Ohki
K
K
Department of Microbiology, Saga Medical School, Japan.
Amano
F
F
Yamamoto
S
S
Kohashi
O
O
D000818:Animals; D002460:Cell Line; D018950:Lipopolysaccharide Receptors / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000737:chemistry / Q000276:immunology*; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis*; D012333:RNA, Messenger; D012710:Serum Albumin, Bovine / Q000276:immunology; D013329:Structure-Activity Relationship; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D012710:Serum Albumin, Bovine; D009569:Nitric Oxide