Eosinophils in our Immunity While Eosinophils account for less than 5% of our white blood cells, they pack quite a punch (Jackson et al., 2022). Most people have likely heard about eosinophils in terms of their role in allergies, but their original purpose is to fight parasites (Vieira et al., 2026). Eosinophils are a type of white blood cell we call granulocytes. They’re named because they store toxic granules which they use to fight and kill infections. But this is far fro