| Objective:Bronchial asthma (asthma) is a chronic inflammatory disease and its pathological features are airway inflammation, AHR and airway remodeling. The pathogenesis of asthma involves a variety of inflammatory cells, which include eosinophils, basophils, lymphocytes, neutrophils, mast cells etc. Chemokines play an important role in the process of activation and migration of inflammatory cells. T helper (Th) cells are divided into Thl and Th2by producing characteristic cytokines. The current researches indicate the imbalance of Thl/Th2is an important immunological mechanism of asthma. Th cells express different chemokine receptors which recruit Th cells into different organ. During the differention of naive T cells to a Thl or Th2, a distinct chemokine receptor expression pattern was demonstrated:the Thl cells expressed CCR5and CXCR3, whereas the Th2cells expressed CCR3, CCR4and CCR8. The present study was designed to determine the effect of HSP70/CD80DNA vaccine on airway inflammatory and hyperresponsiveness in asthma mice through the chemokine and its receptor to regulate the Thl/Th2balance.Methods:HSP70/CD80DNA plasmid and pVAX1plasmid were prepared.40healthy female BALB/c mice were randomly divided into control group (group A), asthma group (group B), vector group (group C) and vaccine group (group D) and each group included10mice. Mouse model of asthma was established by OVA-sensitized in group B, group C and group D. Then, mice in group C and group D were respectively injected with pVAX1plasmis and HSP70/CD80DNA vaccine. Mice in group A and group B were injected with NS at the same time.24h after the last OVA challenge, airway responsiveness (AR) were measured using whole-body plethysmography. Blood from eyepit was collected and the concentration of IgE was detected in serum. The pathological changes of lung tissue were observed by staining with hema-toxylin and eosin (HE). CCL5and CCL17were detected by immunohistochemical method. The levels of CCR5and CCR4mRNA in lung tissue were examined using Real-Time PCR.Results:1. Airway resistance in mice:after sensitized with various concentrations of methacholine, the AR of mice in group B and group C was significantly higher than mice in group A and group D. AR of mice in group B and group C mice were significantly higher than mice in group A (P<0.05), the AR of mice in group C is lower than that of mice in group B (P<0.05) at methacholine concentration of24mg/ml and48mg/ml.2.The changes of pulmonary histopathology:it can be seen the infiltration of inflammatory cells around the bronchi, small blood vessels and alveolus in HE-stained lung tissues of mice in group B and group C. HSP70/CD80DNA vaccine can effectively decrease the airway and perivascular inflammatory response in mice of group D. It is showed the airway epithelial goblet cell hyperplasia/hypertrophy, PAS coloring cells significantly increased, and the lumen of a large number of mucus secretion in PAS stained lung tissues of mice in group B and group C. PAS staining cells and intraluminal mucus secretion was significantly reduced in mice of group D (P<0.05).3.The concentrations of IgE in serum:the concentration of IgE in mice of group B and group C were higher than group A. The concentration of IgE in mice of group D decreased significantly (P<0.05).4. The results of Immunohistochemistry:immunohistochemical result showed that CCL5and CCL17were expressed in epithelial cells of lung tissues. The expression of CCL5in mice of group B and group C was negative or weakly positive; CCL5expression in mice of group A and group D was positive or strongly positive. The protein expression of CCL17in mice of group B and group C was positive or strongly positive; CCL17expression in mice of group D was negative or weakly positive.5. CCR5and CCR4mRNA expression in lung measured by Real-Time PCR:the expression of CCR4mRNA in mice of group B and group C were increased (P<0.05); the expression of CCR4mRNA in mice of group D decreased significantly (P<0.05). The expression ratio of CCR5/CCR4mRNA in mice of group B and group C were decreased (p<0.05); the expression ratio of CCR5/CCR4mRNA in mice of d group increased significantly (P<0.05).Conclusion:1. In this study, we established successfully an acute asthma mouse model by OVA. There were airway inflammation and airway hyperresponsiveness in the asthmatic mice model.2. After treatmenting acute asthma, HSP70/CD80DNA vaccine can reduce airway resistance, mucus secretion and airway inflammation.3. Results show that HSP70/CD80DNA vaccine can enhance the expression of CCL5in airway epithelial cell and reduce CCL17expression. HSP70/CD8DNA vaccine can also increase the expression of CCR5, decrease the expression of CCR4, upregulate the ratio of CCR5/CCR4, thereby restore the balance of Thl/Th2. HSP70/CD80DNA vaccine, as a new immunomodulator vaccine, play an important role in the treatment of asthma and provide experimental basis for the vaccine. |
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