Résumé
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.
Résumé
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.