In an inflammatory response, macrophages are usually derived from -
When a monocyte enters damaged tissue through the endothelium of a blood vessel, a process known as the leukocyte extravasation, it undergoes a series of changes to become a macrophage. Reff: Ananthanarayanan & Panikers textbook of microbiology 9th edition pg: 137
Monocytes
Reticuloendothelial cells
Neutrophils
Lymphocytes
Immunology