Growth requirements of murine bone marrow macrophages in serum-free cell culture.

A serum-free medium for mass production of pure murine bone marrow-derived macrophages in liquid culture was developed. Iscove's modified Dulbecco's medium (IMDM) was used as a basal nutrient medium supplemented with 2-mercaptoethanol, transferrin and a source of colony-stimulating factor (CSF). Addition of exogenous lipids or bovine serum albumin was not required. The macrophages can be kept viable for at least eight days in the serum-free culture medium, and they are able to incorporate tritiated thymidine. The tritiated thymidine incorporation can be enhanced by retinoic acid, phorbol myristate acetate (PMA), colony-stimulating factor (CSF) and transferrin. Prostaglandin E1, prostaglandin E2 and dexamethasone inhibited tritiated thymidine incorporation. The serum-free culture of bone marrow-derived macrophages has some important implications. First, signal molecules can be defined which enhance or inhibit the proliferative capacity of bone marrow-derived macrophages. Second, the fatty acid composition of membrane phospholipids can be altered to study the relationship between macrophage function and membrane lipid composition.