Figure 6. Endotoxin contamination with a TLR2 agonist is responsible by airway neutrophilia observed in mice sensitized with B. tropicalis allergens plus eLPS.

C57BL/6 (WT), TLR2^−/− or TLR4^−/− mice were sensitized twice with Bt or Bt containing PAM3CSK4 (PAM) co-adsorbed to alum and challenged twice with Bt. Control group consisted of non-manipulated animals. The experiments were performed 24 h after the last Bt challenge. Same protocol was conducted using OVA as allergen instead Bt. Eosinophil (A) and neutrophil (B) counts in BAL fluid. Representative dot plot analysis of eosinophils (Gr-1^Low/Siglet-F^High) and neutrophils (Gr-1^High/Siglec-F^low) of mice sensitized in the presence of PAM3CSK4 (c). Intracellular staining for IL-4, IL-5 and IL-17 cytokine production (D), and BAL neutrophils counts (E). Results are expressed as mean ±SEM for groups of five mice and are representative of two experiments. *Significant difference (p<0.05) when compared with Bt group.