Monocyte

A type of leukocyte (agranulocyte type). Monocytes are usually found in lymph nodes, spleen, bone marrow, and connective tissue. Monocytes generally circulate in the system for 1-2 days, before transforming into macrophages when they enter the body tissues. Macrophages are designed to fight infection by engulfing foreign invaders. Monocytes usually arrive at the site of the infection right after neutrophils.