Updated project metadata. The cytokine interleukin-33 (IL-33) is an epithelial alarmin with critical roles in allergic inflammation and type 2 immunity. The project aims at the characterization of the direct cleavage of IL-33 by allergen proteases, resulting in its activation, and in the subsequent induction of type 2 cytokine production in group 2 innate lymphoid cells. The present dataset contains mass spectrometry analyses to map the cleavage sites for 9 distinct allergens proteases in the human IL-33 sequence.