Figure 2. Knockdown of PTPN2 causes increased sensitivity of T-cell lines to cytokine stimulation.

1. Western blot analysis of WCL showing increased sensitivity of JURKAT cells to cytokine stimulation (IFNγ) due to decreased PTPN2 expression. Stimulated cells expressing reduced levels of PTPN2 displayed an increased and prolonged phosphorylation of STAT1 as well as JAK1 (right panel). Results of two independent experiments are shown. ERK1/2 was used as loading control. Open bars: siRNA PTPN2; closed bars: siRNA control; bars show average ± s.e.m., n=3; error bars represent s.e.m. *p<0.05, **p<0.005
2. HPB-ALL cells expressing reduced (siRNA PTPN2) or normal levels (siRNA control) of PTPN2 were stimulated with different concentrations of IL7 for indicated time points and WCL were analyzed for activation of STAT5 and JAK1 by western blot. Quantification of western blot experiments showed that knockdown of PTPN2 resulted in stronger activation of JAK1 and STAT5. Normalized quantification values calculated as fold- change compared to unstimulated cells are shown below respective immunoblots. ERK1/2 was used as loading control.