Regulatory T cells (Tregs) play a non-redundant role in maintenance of immune homeostasis. This is achieved by
suppressing both, priming of naı¨ve cells and effector cell functions. Although Tregs have been implicated in modulating
allergic immune responses, their influence on distinct phases of development of allergies remains unclear. In this study, by
using bacterial artificial chromosome (BAC)-transgenic Foxp3-DTR (DEREG) mice we demonstrate that the absence of
Foxp3+ Tregs during the allergen challenge surprisingly does not exacerbate allergic airway inflammation in BALB/c mice. As
genetic disposition due to strain specificity may contribute significantly to development of allergies, we performed similar
experiment in C57BL/6 mice, which are less susceptible to allergy in the model of sensitization used in this study. We report
that the genetic background does not influence the consequence of this depletion regimen. These results signify the
temporal regulation exerted by Foxp3+ Tregs in limiting allergic airway inflammation and may influence their application as
potential therapeutics.