The clone FUT4/815 recognizes CD15, a cell surface protein (~220 kDa) abundantly expressed by granulocytes and monocytes. CD15 plays important role in mediating phagocytosis, bactericidal activity, and also chemotaxis. CD15 is also expressed by Reed-Sternberg cells and some other epithelial cells. CD15 is very useful in the identification of Hodgkin s disease and also large cell lymphomas of both B and T phenotypes.