The Effect of Natural Killer T Cells on the Pathogenesis of Allergic Asthma Challenged With House Dust Mite Extracts

Abstract

Objective To explore the effect of natural killer T (NKT) cells on the pathology of allergic asthma sensitized with house dust mite extracts(HDM). Methods A total of 16 specific pathogen free (SPF) BALB/c mices were included in the study, and randomly divided into research group (n=8) and control group(n=8). Research group was sensitized by HDM to generate the murine model of asthma.Control group was treated with phosphate buffered saline (PBS) instead of HDM. Airway hyperactivity (AHR) was analyzed by pulmonary impedance method. The level of IL-4 and IFN-γ in bronchoalveolar lavage fluid(BALF) and the level of total IgE were detected by ELISA. The mRNA expression of T-bet and GATA-3 was measured by RT-PCR. The number of NKT and the proportion of mature cells were analyzed by flow cytometry. Results Compared to control group, AHR of research group was increased significantly(P<0.01). The total cells and eosinophils (EOS) of BALF in research group were significantly higher than those of control group(P<0.01). There had significant differences in the level of IL-4, IFN-γ and total IgE in BALF between two groups(P<0.01). There also had significant differences in the mRNA expression of T-bet, GATA-3, the number of NKT cells and the proportion of mature cells between two groups(P<0.01). The number of NKT cells and the proportion of mature cells had positive correlation with the expression of T-bet (r=0.767, P<0.01; r=0.757, P<0.01), and had negative correlation with the expression of GATA-3(r=-0.8871, P<0.01; r=-0.727, P<0.01). Conclusions The NKT cells might play an important role in the pathology of murine model of asthma challenged with HDM extracts. Key words: natural killer T cells; asthma; mice