A nematode immunomodulator suppresses grass pollen-specific allergic responses by controlling excessive Th2 inflammation

► An animal model of allergic asthma using the clinically relevant allergen Phl p 5b was established. ► Filarial cystatin (AvCystatin) showed down-modulatory capacity in this model. ► AvCystatin decreased levels of Th2 cytokines and mast cell degranulation and increased levels of cystatin-specific IL-10. ► AvCystatin modulated allergen-specific responses of human PBMCs from grass pollen allergic patients.