Human macrophage lectin specific for galactose/N-acetylgalactosamine is a marker for cells at an intermediate stage in their differentiation from monocytes into macrophages

• Published in: International immunology 2002-06, Vol.14 (6), p.545-554
• Main Authors: Higashi, Nobuaki, Morikawa, Akiko, Fujioka, Kouki, Fujita, Yuko, Sano, Yoshihiko, Miyata-Takeuchi, Megumi, Suzuki, Noriko, Irimura, Tatsuro
• Format: Article
• Language: English
• Subjects: Acetylgalactosamine - metabolism; Antibodies, Monoclonal; Cell Differentiation; Female; Galactose - metabolism; Gene Expression; Humans; In Vitro Techniques; Lectins - genetics; Lectins - metabolism; Macrophages - cytology; Macrophages - immunology; Macrophages - metabolism; Monocytes - cytology; Monocytes - immunology; Monocytes - metabolism; Phenotype; Skin - cytology; Skin - immunology
• ISSN: 0953-8178; 1460-2377
• DOI: 10.1093/intimm/dxf021

We studied the expression of a human macrophage lectin specific for galactose/N-acetylgalactosamine (hMGL) during macrophage differentiation. The expression of hMGL during the in vitro differentiation induced by human serum was examined by immunostaining and Western blotting with a specific mAb, MLD-1, as well as with RT-PCR analysis. hMGL was detected on cells at an intermediate stage of differentiation. These cells were round, slightly larger in size (12.7 +/- 0.2 microm) than monocytes (9.8 +/- 0.1 microm) and expressed the macrophage marker CD14, but lacked the dendritic cell marker CD1a. The highest levels of expression occurred after 2-4 days of culture. At this time point, MLD-1 prominently stained 20-40% of the cells. Monocytes cultured for 16 h or fully differentiated monocyte-derived macrophages were negative or weak for hMGL expression. Similar transient expression was also observed during granulocyte macrophage colony stimulating factor- or macrophage colony stimulating factor-dependent macrophage differentiation. The lectin was characterized as a functional endocytic receptor for glycosylated macromolecules, since the uptake of carbohydrate polymers was partially inhibited by the addition of MLD-1. The distribution of hMGL(+) cells in normal human skin was found by immunostaining to be mainly in the upper dermis distant from vascular structures. More than 90% of the hMGL(+) cells were double stained with anti-CD68 mAb and constituted approximately 20% of the CD68(+) cells. We suggest that the dermal hMGL(+) cells are a subset of differentiated cells derived from monocytes and that hMGL is a unique marker for cells at an intermediate stage of macrophage differentiation.