Heterogeneity in wheat germ agglutinin binding by mouse peritoneal macrophages

The binding of the lectin wheat germ agglutinin (WGA) to the cell surface of monocytes and macrophages obtained from the stimulated peritoneal cavity of mice was investigated electron microscopically, using ovomucoid-gold as an indirect marker. Resident (tissue) macrophages, identified by the presence of PO activity in the rough endoplasmic reticulum as well as in the nuclear envelope, showed low WGA binding, whereas monocytes and monocyte-derived macrophages with PO activity in the granules showed high WGA binding. Since cells devoid of PO activity showed variable WGA binding, the value of this gold-WGA-binding technique for discrimination on a quantitative basis between resident macrophages and monocytes or monocyte-derived macrophages, is discussed.