The effects of serum on the in vitro adherence and maturation of bovine monocytes.

Serum concentration was found to affect both the initial adherence and subsequent in vitro maturation of bovine monocytes. Bovine monocytes cultured in the absence of serum remained small and reduced in number, whereas monocytes cultured in an adequate concentration of either autologous adult bovine or fetal bovine serum developed into large macrophage-like cells. Heat inactivation (56 degrees C for 30 minutes) did not affect the ability of bovine sera to promote monocyte maturation in vitro.