Fig. 4

a and b Protein expression of tumor necrosis factor (TNF)-α and interleukin (IL)-6 was determined by enzyme-linked immunosorbent assay, and that of inducible nitric oxide synthase (iNOS) was determined by Western blot analysis following treatment with soluble sialic acid-binding immunoglobulin-type lectin (sSiglec)-9 (0–20 ng/ml) for 24 h. Expression of β-actin was used as a control. The expression of all M1 markers was significantly suppressed by sSiglec-9 treatment. *p < 0.05, **p < 0.01 (Bonferroni post hoc test). c Western blot analysis revealed that sSiglec-9 treatment dose-dependently decreased the interferon (IFN)-γ-stimulated phosphorylation of nuclear factor (NF)-kB p65, while the phosphorylation of p38 was not affected. d Celastrol, a specific inhibitor of NF-kB, significantly inhibited the IFN-γ-stimulated increase in TNF-α messenger RNA (mRNA) expression. However, SB202190, a specific inhibitor of p38/mitogen-activated protein kinase, did not affect TNF-α mRNA expression. **p < 0.01 versus samples stimulated with IFN-γ without sSiglec-9 treatment (Bonferroni post hoc test). GAPDH glyceraldehyde 3-phosphate dehydrogenase, n.s. not significant