Identification of fish macrophage and its DNase activity in the podosomes. Cells harvested from fish scales consist of macrophages and keratocytes. The macrophage was identified with specific antibody (anti-TNF-α), and the expression of TNF-α was correlated with formation of podosomes and DNase activity. Therefore, one can distinguish macrophages from keratocytes simply by observing the SNS signal produced by cells. By estimate, ∼10–30% of cells harvested from fish scales are macrophages.