Objective: To investigate whether M. vaccae inhalation affects asthma via γδ T cell regulation.
Methods: Forty male Balb/c mice were randomly divided into 4 groups: normal group, asthma group, control group and intervention group. The normal group was given no treatment. For the asthma group, control group and intervention group, the mice were sensitized and stimulated with ovalbumin (OVA) to establish asthma models. Mice in the asthma group were not treated. Mice in the control group were treated with γδ T cell suspension from normal mice, and those in the intervention group were treated with γδ T cell suspension from mice intervened by Mycobacterium bovis. ELISA assay was adopted for quantification of IL-4 and IFN-γ in mouse alveolar fluid (BALF), and flow cytometry for determining the percentage of IL-4 and IFN-γ from mononuclear cells of lung tissues.
Results: The airway responsiveness of the asthma group was higher than that of the normal group. The degree of airway inflammation in the intervention group was lighter than that in the control group, and it was significantly alleviated compared with the asthma group (P<0.05). Compared with the asthma group, the level of IL-4 in the BALF of the control group and the intervention group decreased significantly, while the level of IFN-γ increased significantly (P<0.05). Compared with the control group, the level of IL-4 in the BALF of the intervention group was significantly lower, while the level of IFN-γ was significantly higher (P<0.05). In addition, the results of flow cytometry were basically consistent with the results of Elisa.
Conclusion: Aerosol inhalation of Mycobacterium bovis can alleviate the Th2 dominant immune response induced by OVA sensitization and regulate the Th1/Th2 immune imbalance in patients with asthma.
Keywords: Asthma; Mycobacterium bovis; adoptive immune γδ T cells; aerosol inhalation; airway inflammation; cytokines.
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