Aminopeptidase as a marker for macrophage differentiation

Thioglycolate medium, rich in peptides, causes an inflammation reaction in mice upon i.p. injection. It induces from the 2nd to the 6th day an increase in aminopeptidase, an enzyme bound to the plasma membrane of macrophages. This increase is up to 30-fold per cell and is due to a 10–20-fold increase in enzyme concentration per unit area of the membrane.