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Keywords:

  • Airway inflammation;
  • CD47;
  • DC;
  • Signal regulatory protein a;
  • Th2

Abstract

The interplay between innate and adaptive immune responses is essential for the establishment of allergic diseases. CD47 and its receptor, signal regulatory protein α (SIRP-α), govern innate cell trafficking. We previously reported that administration of CD47+/+ but not CD47−/− SIRP-α+ BM-derived DC (BMDC) induced airway inflammation and Th2 responses in otherwise resistant CD47-deficient mice. We show here that early administration of a CD47-Fc fusion molecule suppressed the accumulation of SIRP-α+ DC in mediastinal LN, the development of systemic and local Th2 responses as well as airway inflammation in sensitized and challenged BALB/c mice. Mechanistic studies highlighted that SIRP-α ligation by CD47-Fc on BMDC did not impair Ag uptake, Ag presentation and Ag-specific DO11.10 Tg Th2 priming and effector function in vitro, whereas in vivo administration of CD47-Fc or CD47-Fc-pretreated BMDC inhibited Tg T-cell proliferation, pinpointing that altered DC trafficking accounts for defective Th priming. We conclude that the CD47/SIRP-α axis may be harnessed in vivo to suppress airway SIRP-α+ DC homing to mediastinal LN, Th2 responses and allergic airway inflammation.