| OBJECTIVE: The prevalence of allergic rhinitis(AR) and asthma has increased steadily over the past 3 decades. They are two kinds of common allergic disease endanger the health of human beings and there is a lack of effective prevention and therapeutic measures. Abnormal immunological responses is induced by altered environmental conditions in cases of AR and asthma. The disequilibrium of Th1/Th2 touches off the allergic inflammation, especially Th2 immunologic response, in the nasal cavity and bronchial mucosa. Modulating the Th1/Th2 balance may represent a new strategy of preventing and curing AR and asthma. IL-12 is an important immunoloregulation factor,which strongly promotes the differentiation of Th1 cell, while the lymphocytes contacting with the allergen. Simultaneously, IL-12 maintains the Th1 allergic response and promotes the active Th1 cell and NK cell to excrete IFN-γ and IL-2, which suppress the expression of Th2 cytokines and the synthesis of IgE and reduce the Th2 allergic response.To gain the high and steady level of bioactivity of IL-12 both in vitro and vivo, we constructed a single-chain IL-12 DNA plasmid, in which the two IL-12 subunits(p35 and p40) were linked by a 54bp polypeptide linker and then transferred into the plasmid. The local transfer of the single-chain IL-12 DNA plasmid modifies the allergic inflammation in the airway.Early periodic infections play an important role in modulating the Th1/Th2 balance. Infection of tuberculosis or pertussis in childhood may improve the immune system,including total body and local pulmonary immune system, which can build up a Th1 immune response enviroment of Th1 profiles cytokines such as IFN-γ,IL-12 and TNF. Meanwhile, these Th1 cytokines suppress the function of Th2 cytokines and redress the disequilibrium of Th1/ Th2. BCG , an attenuated strain of living bovine tubercle bacillus and a inducer of strong Th1 immune response, could direct the response to Th1 and decrease the occurrence of allergic diseases.In this study, we investigated the intervention function of recombination IL-12 DNA and nonspecific immunoloregulation BCG in AR and asthma. we observed the intervention of recombination IL-12 in AR in mature mice and its association with BCG-inoculation at early stage to suppress the allergic inflammation in the OVA-induced allergic mouse models. This intervention could decrease the Th2 reaction and specific IgE and suppress the allergic inflammation in the airway. Our study may provide a new strategy in developing the vaccine of atopic diseases and the prevention of AR and asthma.METHODS:1.The expression of pcDNA/IL-12 in eukaryon cells is identified PCR and DNA sequencing. pcDNA3.1(+) and pcDNA/IL-12 were transfected into COS-7 cells and their expression in eukaryon cells were evaluated by PT-PCR,ELISA and Western Blot.2. 20 6-week-aged BALB/c mice were divided into cast and control groups by random. Mice were sensitized by intraperitoneal and subcutaneous injections of OVA and AL(OH)3 twice,then received 6 consecutive airway OVA by aerosolization to induce the airway inflammation, AR and asthma. The serum samples were obtained to determine the OVA-specific IgE antibody titers. The BALF were obtained through the BAL to determine the proportion of EOS. The pathological changes were observed in the pulmonary tissues and the expression of IL-4mRNA of lymphocytes in local airway were evaluated by immunohistochemistry. 3. pcDNA3.1 and pcDNA/IL-12 plasmids were gained in great deal according to the QIAGEN introduction. The content of plasmids was evaluated by polynucleotide quantu machine and the purity by spectrophotometer. Plasmids were dissolved into NS to a concentration of 1mg/ml. 4.mature mice were divided into 3 groups by random: psIL-12, pcDNA3.1(+) control and PBS control. Each group contained 10 mice. All mice were sensitized and provoked with OVA to establish the animal models of airway inflammation. A single dose of psIL-12, pcDNA3.1(+), PBS-lipid complex was appli...
|
PDF Full Text Request