Fish Immunology (1+1)

Unit 4- Fish Leucocytes

4.2. Monocytes/Macrophages
Macrophages differentiated from mononuclear cells derived from circulating blood monocytes. In fish macrophages are mainly involved in phagocytosis which is one of the most ancient immune mechanism, and macrophages were observed in almost all lymphoid tissues. Several subpopulations of macrophages are also present in fish. Distribution of macrophages in the fish is species dependent but these macrophages are commonly observed in both lymphoid organ (spleen, kidney, and thymus) and non lymphoid organ (liver, gonads, and heart) tissue. The environmental change influence on the size, pigmentation, and number of macrophages.