Significant upregulation of cytokine secretion from T helper type 9 and 17 cells in a NC/Nga mouse model of ambient chemical exposure-induced respiratory allergy.

It has been reported that ambient chemical exposure is closely associated with respiratory allergies. We attempted to develop an original protocol for detecting ambient chemical exposure-induced respiratory allergy in different strains of mice. In the process of comparing allergic potency of these mice, we observed that NC/Nga mice showed significant upregulation of respiratory allergic symptoms as well as specific type of cytokine secretions. The main purpose of this study was to investigate the mechanism underlying these phenomena in NC/Nga mice in comparison with BALB/c mice. For the model of respiratory allergy, female BALB/c and NC/Nga mice were sensitized and challenged with trimellitic anhydride. Clinical observation, IgE and immunocyte counts, and cytokine profile in the serum, lymph nodes, and bronchoalveolar lavage fluid were recorded. We also monitored the expression of genes encoding pro-inflammatory cytokines in the lung. We found that worsening of respiratory status was noted only in NC/Nga mice, whereas Th2 reactions were significantly increased in BALB/c mice compared with NC/Nga mice. In contrast, the levels of Th9 and Th17-derived cytokines in NC/Nga mice were significantly higher than those in BALB/c mice. Thus, Th9 and Th17 may be involved in the aggravation of respiratory allergic symptoms induced by ambient chemicals.