Eosinophils are a type of white blood cell that plays a role in the immune response against parasitic infections and allergic reactions. They are characterized by their large, brightly colored granules in their cytoplasm and are involved in the regulation of inflammation and tissue repair. Eosinophils are also implicated in various diseases, including asthma, allergies, and certain autoimmune disorders. Research on eosinophils often focuses on understanding their function in the immune system and developing new treatments for diseases associated with eosinophil dysfunction.