ABSTRACT
Aim To investigate the optimal condition for expression of pCI-neo-IL-1ra-Fc? plasmid for gene therapy and its immune response in rats.Methods Different doses(0.25,0.5,2.5 mg?kg-1)pCI-neo-IL-1ra-Fc? plasmid were instilled into lungs of rats through tracheas,then expressions of IL-1ra-Fc? fusion protein were detected at different interval times(d 4,d 7,d 20)by RT-PCR and Western blot.Through immu-nohistochemistry analysis of rat lungs,those results of optimal condition were validated.Dynamic changes of rat serum IgG level,including IgG2a and IgG1 were detected by indirect ELISA.Results IL-1ra-Fc? could be detected at 20th day after instilling pCI-neo-IL-1ra-Fc? plasmid in all dose groups.The expression level in 2.5 mg?kg-1 groups was higher than that in other two groups.IL-1ra-Fc? protein could not be expressed at 4th day,but increased at 7th day and reached maximum at 20th day after instillation.IL-1ra-Fc? gene could be efficiently expressed in rat lungs by immunohistochemistry analysis.Humoral immunity of rats was induced by pCI-neo-IL-1ra-Fc? plasmid.IgG2? expression was predominant in IgG subsets,showing that the humoral immunity was Th1-like immune response.Conclusion The optimal condition is established for gene therapy with pCI-neo-IL-1ra-Fc? plasmid which can induce Th1-like immune response in rats.