Generation of macrophage variants with 5-azacytidine: selection for mannose receptor expression.

Mannose receptors are expressed only in primary macrophages. Established macrophage-derived cell lines, although apparently possessing the potential to synthesize mannose receptors, do not express them on their plasma membranes. Using the drug 5-Azacytidine, mannose receptor expression was induced in the macrophage-derived mouse cell line J774. Receptor positive cells were sorted through a fluorescent activated cell sorter (FACS) prior to cloning. Clones were isolated which continuously express mannose receptors in culture. These macrophages were able to endocytose beta-glucuronidase and phagocytose yeast particles via mannose receptors. Secretion of the lysosomal enzyme beta-hexosaminidase was also reduced in proportion to the degree of mannose receptor expression.