Effects of Foxp3 transfection on splenocyte functions in asthma mice

AIM: To study the expression and the effects of Foxp3 on the immunologic functions by transfecting the Foxp3 eukaryotic expression plasmid into the splenocytes of the asthma mice. METHODS: The mice were sensitized and challenged by ovalbumin to make asthma model. The splenocytes were harvested and cultured. The Foxp3 expression vector pcDNA3.1(-)-Foxp3 was transfected into the splenocytes with electroporation. The splenocytes transfected with empty vector and control splenocytes (non-transfected) were also set up. The expression of Foxp3 at mRNA and protein levels was detected by RT-PCR and Western blotting, respectively. The proportion of CD4⁺CD25⁺ Treg cells/CD4⁺ cells was measured by flow cytometry. Proliferation of the splenocytes was analyzed with MTT assay. ELISA was used to determine the levels of interleukin 4 (IL-4) and interferon γ (IFN-γ) in the supernatant of the splenocytes. RESULTS: The expression of Foxp3 at mRNA and protein levels in transfection group was significantly higher than that in empty vector group and control group. The proportion of CD4⁺CD25⁺Treg cells/CD4⁺ cells in transfection group was higher than that in empty vector group and control group. The proliferation of transfected cells was markedly inhibited compared with empty vector group and control group. The levels of IL-4 and IFN-γ were significantly lower in transfection group than those in empty vector group and control group. CONCLUSION: The transfected Foxp3 gene overexpresses in the splenocytes of asthma mice. Foxp3 increases the number of CD4⁺CD25⁺ T cells and inhibits the proliferation and production of Th1/Th2 cytokines in splenocytes.