monocyte

Last reviewed 01/2018

Monocytes are the largest type of white blood cell on the peripheral blood smear - 16-20 micrometers in diameter. They are the precursors of macrophages. Together, the two types of cell make up the reticulo-endothelial system.

Monocytic function includes:

• transforming into a macrophage at the site of inflammation in order to undertake phagocytosis
• processing antigen for lymphocyte recognition
• the removal of senescent blood cells

Monocytes are formed in the bone marrow and emerge to form either locally-fixed macrophages in various connective tissues e.g. that of the liver, lymph nodes and central nervous system, or circulating precursors of more differentiated scavenger cells. Their circulating life is about 3 days.