The function common to neutrophils, monocyte & macrophages is -

Phagocytes Micro-organisms entering the tissue fluid or bloodstream are very rapidly engulfed by the cells called phagocytes. Phagocytic cells are of two types : Mononuclear macrophages: Monocytes (blood), histiocytes (tissues), alveolar macrophages (lung), kupffer cells (liver), microglia (brain), osteoclasts (bone), and mesangial cells (kidney). Polymorphonuclear microphages: Neutrophils. Basophils also belong to polymorphonuclear microphages but they are not phagocytes. Eosinophils have only a limited degree of phagocytic activity.