The study will include a Screening period of up to 21 days, during which subject eligibility will be assessed and Screening responses to endotoxin exposure challenge will be collected. Eligible subjects will initially undergo an 8-day treatment period, during which they will receive treatment based on their assigned cohort (or will receive no treatment if assigned to Cohort 1) and will be applied with the endotoxin challenges. After the treatment period, subjects will be followed up until study Day 42.