Prior to analyzing the in vivo antipseudomonal efficacy of exogenous AMPs, the ability of the selected peptides [i.e. Esc(1–21), Esc(1–21)-1c and LL-37] to elicit host immune response and eventually lead to pulmonary toxicity upon intra-tracheal delivery, was evaluated at 24 hours after their administration. The peptides were tested at a concentration of 20 μM (2 μg/mouse) and 64 μM (7 μg/mouse).