Blockade of IL-23 ameliorates allergic lung inflammation via decreasing the infiltration of Tc17 cells.

INTRODUCTION: Tc17 cells are interleukin (IL)-17-producing CD8(+) T cells and have been found to participate in the development of allergic asthma. Interleukin-23 is a cytokine that may be involved in modulating the IL-17 response via Th17 cells. This study aimed to investigate whether IL-23 also has immunomodulatory effects on Tc17 cells.

MATERIAL AND METHODS: An allergic asthmatic mouse model was induced by sensitizing and challenging with ovalbumin (OVA). Anti-IL-23 antibody was administered intratracheally before challenge to the OVA-induced asthmatic mouse model. Airway hyperresponsiveness, lung inflammation, Tc17 cell percentages and IL-17 level in the lung tissue homogenate were measured.

RESULTS: Anti-IL-23 treatment reduced airway hyperresponsiveness (Rn 2.471 ±0.5077 vs. 4.051 ±0.2334, p < 0.05), inflammatory cell infiltration in bronchoalveolar lavage fluid (eosinophils 140.0 ±9.869 vs. 222.4 ±31.55, p < 0.05, neutrophils 75.93 ±6.745 vs. 127.4 ±19.73, p < 0.05), airway inflammation and mucus secretion. Treatment with anti-IL-23 antibody also markedly reduced IL-17 level (398.1 ±28.74 vs. 590.6 ±36.13, p < 0.01) and percentage of Th17 and Tc17 cells in lung tissue homogenate (4.200 ±0.1581 vs. 9.314 ±1.027, p < 0.01 and 2.852 ±0.2566 vs. 5.588 ±0.3631, p < 0.01, Th17 and Tc17 cells respectively).

CONCLUSIONS: Our data suggest that the IL-23/Tc17 cell axis may be involved in the pathogenesis of asthma as the complement of IL-23/Th17 cells.