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Objective To investigate the role of CD4+CD25+FoxP3+ in severe Mycoplasma pneumonia among children.Methods One hundred and forty children with M.pneumoniae pneumonia (65 severe and 75 non-severe) who were hospitalized were enrolled along with forty other children as controls.X-ray was assessed.The proportions of peripheral blood CD4+CD25+FoxP3+cells were determined by flow cytometry.Results Both severe and non-severe children had decreased CD4+CD25+FoxP3+cells as compared with control subjects in acute phase (0.87 ± 0.66％ vs.3.88 ± 2.00％,P ＜ 0.01 and 1.17 ± 0.70％ vs.3.88 ±2.00％,P ＜0.01,respectively).The levels of CD4+CD25+FoxP3+cells in severe children were lower than those in non-severe children in acute phase and recovery phase (0.87 ±0.66％ vs.1.17 ±0.70％,P ＜0.05 and 1.66 ±0.85％ vs.3.61 ± 1.45％,P＜0.01,respectively).Both severe children and non-severe children expressed higher CD4+CD25+FoxP3+cells in recovery phase than in acute phase (1.66 ± 0.85 ％ vs.0.87 ± 0.66％,P ＜0.01 and 3.61 ± 1.45％ vs.1.17 ±0.70％,P ＜0.01,respectively).Conclusion The expression of CD4+CD25+FoxP3+Tregs may play a role in the onset of severity of mycoplasma pneumonia and the low express of CD4+CD25+FoxP3+Tregs in children infected with M.pneumonia may increase the susceptibility to severe mycoplasma pneumonia.
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Nerve growth factor (NGF) promotes neuronal survival and differentiation and stimulates neurite outgrowth. NGF is synthesized as a precursor-proNGF in vivo. In this paper, a pET-proNGF prokaryocyte expression vector was constructed and transformed into E. coli BL21(DE3)pLysS. The proNGF was expressed in the form of non-active aggregated monomer in E. coli after induction with IPTG. SDS-PAGE revealed the proNGF expression product had a Mr.30.2 kD. Western blotting analysis showed that the protein had good antigenicity. Fusion protein was successfully purified by Ni2+-NTA affinity chromatography and cleaved by Enterokinase and 13.1 mg proNGF was obtained from 100 mL cell culture in a typical experiment. The protein was dialyzed in a redox system containing reduced and oxidized glutathione. RP-HPLC was used to analysis the result of the refolding. The refolded proNGF protein can induce neurite outgrowth of PC12 cells, which indicated that pro-form of NGF we obtained had biological activity.