Fig 2: A proposed mechanism of SOD3 on IgE production in B cells. Ligations of LPS or anti CD40 along with IL-4 on B cells trigger the activation of JAK-STAT, p38, JNK, and NFκB signaling events which result in the secretion of IgE and chemokines. SOD3 suppressed the activation of these cellular signals and thus controls the release of IgE and chemokines in B cells.

Fig 3: SOD3 inhibits IgE isotype class switching in B cells. (A–B) B cells were pre-treated with SOD3 (100U, 200U and 300U/mL) for 1 h followed by treatment with either (A) LPS (10 μg/mL)/IL-4 10 ng/mL or (B) anti-CD40 (5 μg/mL)/IL-4 (10 ng/mL). Genes involved in CSR were analyzed by RT-PCR. (C–D) B cells isolated from SOD3+/+ and SOD3−/− mice were pre-treated with SOD3 (200U/mL) and then treated with differentiating stimuli and DETCA (10 μM). Genes involved in CSR were analyzed by RT-PCR. All experiments were performed in triplicates. Data are expressed as mean ± standard deviation. The band intensities of gel electrophoresis are presented in supplementary section (Fig. S1). Full length blots are presented in Fig. S2. #p < 0.05, ##p < 0.01, ###p < 0.001 (Control group vs. LPS/IL-4 or anti-CD40/IL-4-treated group); *p < 0.05, **p < 0.01, ***p < 0.001 (LPS/IL-4 or anti-CD40/IL-4-treated group vs. SOD3-treated group); @p < 0.05, @@p < 0.01, @@@p < 0.001 (SOD3+/+vs SOD3−/−).

Fig 4: SOD3 suppressed IgE secretion in B cells. (A–B) B cells were pre-treated with SOD3 (100U, 200U and 300U/mL) for 1 h followed by treatment with either (A) LPS (10 μg/mL)/IL-4 10 ng/mL or (B) anti-CD40 (5 μg/mL)/IL-4 (10 ng/mL). The level of IgE secretion was determined after 5 days of incubation from cell-free supernatant by ELISA. (C–D) B cells were isolated from SOD3+/+ and SOD3−/− mice and pre-treated with SOD3 (200U/mL). The cells were then treated with differentiating stimuli and DETCA (10 μM). The level of IgE was measured by ELISA. All experiments were performed in triplicates. Data are expressed as mean ± standard deviation. #p < 0.05, ##p < 0.01, ###p < 0.001 (Control group vs. LPS/IL-4 or anti-CD40/IL-4-treated group); *p < 0.05, **p < 0.01, ***p < 0.001 (LPS/IL-4 or anti-CD40/IL-4-treated group vs. SOD3-treated group); @p < 0.05, @@p < 0.01, @@@p < 0.001 (SOD3+/+ vs SOD3−/−).