The Prevention of Inflammatory Immune Responses to Inhaled Antigens in Healthy

The prevention of inflammatory immune responses to inhaled antigens in healthy individuals has mechanisms in common with those that prevent inflammatory immune responses to commensal microbes in the gut. One important component of immune regulation shared by these two situations is:

A) The presence of tissue-resident dendritic cells that produce IL-23 when activated
B) The presence of tissue-resident mast cells that bind IgE through the high affinity IgE receptor
C) The high levels of constitutive IL-10 present in the mucosal surfaces of both the airway and the gastrointestinal tract
D) The induction of increased numbers of IFN- $\gamma$ -producing T cells and ILCs in the airway and gastrointestinal epithelium
E) The important role for CD4 regulatory T cells in suppressing inflammatory immune responses in these tissues