A role for galectin-3 in CD13-mediated homotypic aggregation of monocytes.
We recently reported that anti-CD13 mAbs induce homotypic aggregation of monocytic cells. This phenomenon is signal transduction dependent and does not require CD13 aminopeptidase activity. Since CD13 is heavily glycosylated and a member of the galectin family (galectin-4) has been shown to associate with CD13 in the intestinal epithelium, we hypothesized that CD13-mediated aggregation might proceed through a carbohydrate-dependent mechanism involving galectin-3, the most highly expressed galectin on monocytes. We report here that lactose and anti-galectin-3 antibodies completely abrogate homotypic aggregation induced by anti-CD13 antibodies. Furthermore, galectin-3 co-immunoprecipitates with CD13 from resting U-937 cells and this association decreases during the aggregation process, a phenomenon that may have functional implications. Together, the results presented here point to a key role for galectin-3 in CD13-mediated homotypic aggregation of monocytic cells.
Mina-Osorio
Paola
P
Department of Immunology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México, D.F., México. pmina@uchc.edu
Soto-Cruz
Isabel
I
Ortega
Enrique
E
D018826:CD13 Antigens / Q000037:antagonists & inhibitors / Q000276:immunology*; D002449:Cell Aggregation / Q000187:drug effects / Q000276:immunology*; D002462:Cell Membrane / Q000378:metabolism; D037502:Galectin 3 / Q000276:immunology / Q000502:physiology*; D006801:Humans; D007785:Lactose / Q000494:pharmacology; D018448:Models, Immunological; D009000:Monocytes / Q000187:drug effects / Q000276:immunology*; D013395:Sucrose / Q000494:pharmacology; D020298:U937 Cells
D037502:Galectin 3; D013395:Sucrose; D018826:CD13 Antigens; D007785:Lactose