Figure 5.

Protein tyrosine kinase inhibitors PP2 and piceatannol affected the enhancing effect of IVIG on IL-10 production in BMDC stimulated with LPS. Cells (5 × 10⁵/mL) were stimulated with LPS (500 ng/mL) in the presence or absence of IVIG (10 mg/mL) and/or protein tyrosine kinase inhibitors for 18 h. IL-10 production in the culture supernatant was measured using an ELISA kit and results were expressed as mean ± SEM (n = 3). ^## P < 0.01, significantly different from the medium alone (without LPS stimulation, Student's t-test); **P < 0.01, significantly different from the Control (LPS stimulation without IVIG, Dunnett's multiple comparison test); ^¶¶ P < 0.01, significantly different from LPS stimulation with IVIG, Student's t-test. ND, IL-10 concentrations were under the lower limit values of the standard ELISA curves. The enhancing effect of IVIG on IL-10 production was abolished by (a) the Hck/Lyn inhibitor PP2 and (b) Syk inhibitor piceatannol. Three independent experiments were conducted and representative results were shown. The tyrosine phosphorylation of ERK1/2 and Syk in cells was detected by immunoblotting as described in the Materials and Methods. PP2 and piceatannol inhibited ERK1/2 and Syk phosphorylation by IVIG in mouse BMDC stimulated with LPS. (c) ERK1/2; (d) Syk.