Objective and design: In this study, we explored whether prolonged ovalbumin (OVA) exposure in sensitized mice created an environment suitable for Th17 differentiation.
Materials and methods: BALB/c and C57BL/6 mice (n = 36), after intraperitoneal OVA sensitization on days 0 and 12, received prolonged OVA aerosol challenges up to day 55. Airway inflammatory cell levels, cytokine profiles, and Th17 cell infiltration were evaluated after sacrifice.
Results: Prolonged OVA challenge caused inflammation that was characterized by raised influxes of airway macrophages and neutrophils. Following long-term exposure, Th17 cytokines and Th17 cell numbers progressively increased in the lung (P < 0.05) along with increased production of Th17 polarization-related factors, including TGF-beta, IL-6, and IL-23. The lineage-specific transcription factor for Th17 subsets, RORgammat, displayed similar upregulation throughout the OVA challenge (P < 0.05).
Conclusions: Prolonged OVA challenge induces an environment that facilitates Th17 polarization.