Assertion: allergy | /r/HasProperty | immune system reaction
Facets:
value: to a substance
type: CAUSE
Source sentences:
text: Allergies are an immune system reaction to a substance called an allergen.
text: An allergy is an immune system response to a substance the body perceives as harmful.
text: An allergy is the immune system's reaction when exposed to what is otherwise a harmless substance, such as plant pollen , mold, or animal hair , skin or saliva .