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.
Immune response
Phagocytosis
Liberation of histamine
Destruction of old erythrocytes