Standard fla from salmonella typhimurium

For the OVA/FLA model of asthma, mice were sensitized by oropharyngeal (o.p.) instillations of 100 μg endotoxin-free OVA together with 1.25 μg standard FLA from Salmonella typhimurium (InvivoGen, San Diego, CA) on days 0 and 7, then challenged on days 14, 15, and 16 with 1% OVA aerosol. (This FLA preparation signals through both TLR4 and TLR5 because it contains 10³–10⁴ endotoxin units/mg protein). In the HDM model of asthma, mice were sensitized with 1 μg HDM (Greer, Lenoir, NC) by o.p. instillation on days 0 and 7 and challenged by the same route on days 14, 15, and 16. For both models, mice were harvested at 4h post-challenge to examine cytokines and chemokines, and at 24h post-challenge to assess leukocyte recruitment to the airway. For the OVA/IL33 model of asthma, mice were sensitized by o.p. instillations of 100 μg endotoxin-free OVA together with 500 ng IL33 (Biolegend, San Diego, CA) on days 0 and 7, then challenged on days 14, 15, and 16 with 1% OVA aerosol.