Υδ T cells play an important role in the development of RSV-influenced allergic airway inflammation

Abstract

Objective To investigate whether γδ T cells act as a regulatory factor during respiratory syncytial virus (RSV) infections was responsible for the subsequent changes in asthmatic-type inflammation in allergic mice.Methods Mice were sensitized and challenged with OVA,and infected intranasaly with RSV before or after OVA sensitization.Lung sections were stained with HE for determination of inflammatory reaction.Real-time RT-PCR was used to analyze the expression of cytokine mRNA of γδ T cells in the lung and spleen of tested mice.The number of γδ T cells in the spleen and lung of BALB/c mice was determined by flow cytometry.Adoptive transfer of γδ T cells was performed to identify the role of γδ T cells in allergic asthma.Results OVA-sensitized and challenged mice exhibited significantly peribronchial inflammation with larger number of mononuclear cells and granulocytes in the lung tissue sections.RSV infection before OVA-sensitization diminished the grade of inflammatory responses induced by OVA treatment.The expression of IFN-γ mRNA was increased siguificantly in RSV-infected,OVA-sensitized mice.In contrast,the level of IL-4 mRNA was diminished.The number of total γδ T cells as well as activated γδ T cells was decreased in the spleen and lung of OVA-sensitized mice by prior RSV infection.Adoptive transfer of γδ T cells obtained from OVA-sensitized and challenged mice induced a slight inflammation in the lung of normal mice,and enhanced inflammatory responses in RSV-infected OVA-sensitized mice.Conclusion γδ T cells may play an important role in the development of allergen-induced allergic airway inflammation. Key words: Asthma; γδ T cell; Respiratory syncytial virus; Inflammation