Objective To study the changes and significance of CD4+CD25+ regulatory T cells and C-reactive protein(CRP) in patients with acute exacerbation of chronic obstructive pulmonary disease(COPD). Methods Flow cytometry was used to detect the frequency of CD4+CD25+ regulatory T cells in peripheral blood from 36 patients with acute exacerbation of COPD( COPD group) and 36 patients with clinical stability of COPD(control group one)and 36 normal individuals(control group two). The level of CRP was detected routinely. Results The ratio of CD4+CD25+ regulatory T cells number in peripheral blood of COPD group to the total number of CD4+T cell was (2.56±1.83 )%, and it was significantly decreased compared to the other two groups (P all<0.01 ). The level of CRP in COPD group was markedly higher than that in the other two groups (P all<0.01 ). The level of CD4+CD25+ regulatory T cells in patients with acute exacerbation of COPD had negative relation with CRP. Conclusions CD4+CD25+ regulatory T cells participate in inflammatory response. The proportion of CD4+CD25+ regulatory T cells decreases in patients with acute exacerbation of COPD, and it may result in maladjustment of cytoimmunity.

To prepare a soluble human extracellular III domain of Flt1 and analyze its biological activity. The gene encoding extracellular domain III of Flt-1 was cloned into the expression vector pAZY by RT-PCR from human umbilical vein endothelial cell (HUVEC), and induced to express in Escherichia coli by low phosphoric medium, the product was purified by E-tag affinity chromatography. SDS-PAGE and Western blotting analysis showed that Flt-1 gene domain III gene was expressed in E. coli and the yield of the soluble fusion protein was about 1.10 mg/L. Enzyme-Linked ImmunoSorbent Assay (ELISA) revealed that the Flt-1 domain III was able to bind to VEGF165 dose-dependently. Monolayer denudation assay and Transwell assay showed that the fusion protein could inhibit HUVECs migration induced by conditional medium with 50 ng/mL VEGF165 and 100 ng/mL bFGF. In conclusion, Flt-1 gene domain III gene has been successfully cloned and expressed in E. coli, which will be useful in both the research on the function of Flt-1 gene domain III and preparation of anti-Flt-1 monoclonal antibody in the future.
Cloning, Molecular ; Endothelial Cells ; cytology ; metabolism ; Escherichia coli ; genetics ; metabolism ; Extracellular Space ; metabolism ; Genetic Vectors ; genetics ; Humans ; Recombinant Fusion Proteins ; genetics ; isolation & purification ; metabolism ; pharmacology ; Solubility ; Umbilical Veins ; cytology ; Vascular Endothelial Growth Factor Receptor-1 ; genetics ; isolation & purification ; metabolism