title: Hyaluronan receptor (CD44) expression and function in human peripheral blood monocytes and alveolar macrophages.
abstract: CD44 glycoproteins are present on the surfaces of many hematopoietic cells and in some cases can bind hyaluronan, a major component of the extracellular matrix. In the present study, we have found that newly explanted human peripheral blood monocytes (PBMs) exhibit a major CD44 band of 85 kDa, whereas autologous alveolar macrophages (AM phi) express multiple isoforms ranging from 85 to 200 kDa. Within 4 h in culture, PBMs began expressing new CD44 isoforms of 120, 150, and 180 kDa. Newly explanted AM phi specifically bound [3H]hyaluronan (135 cpm/microgram protein), but newly explanted PBMs did not. However, in vitro cultured PBM progressively acquired the ability to bind [3H]hyaluronan and exhibited specific binding of hyaluronan similar to that of AM phi (113 cpm/microgram protein) after 4 days in culture. In both case, the binding of [3H]hyaluronan was specifically inhibited by the addition of monoclonal antibody directed against CD44. AM phi readily degraded [3H]hyaluronan and reached a plateau after 4 days in culture (115 cpm/microgram protein). Newly explanted PBM exhibit no hyaluronan degradation and only a small degradative activity after 4 days in culture (6 to 11 cpm/microgram protein). Thus, CD44 expression and function appear to change as PBM mature in vitro resembling more that found in AM phi.
authors.affiliation: Department of Cell Biology, Georgetown University Medical Center, Washington, DC 20007.
authors.forename: M
authors.initials: M
authors.lastname: Culty
authors.forename: T E
authors.initials: TE
authors.lastname: O'Mara
authors.forename: C B
authors.initials: CB
authors.lastname: Underhill
authors.forename: H
authors.initials: H
authors.lastname: Yeager
authors.forename: R P
authors.initials: RP
authors.lastname: Swartz
mesh_terms: D000328:Adult; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D018960:Hyaluronan Receptors; D006820:Hyaluronic Acid / Q000378:metabolism; D008214:Lymphocytes / Q000378:metabolism; D016676:Macrophages, Alveolar / Q000737:chemistry*; D008297:Male; D008970:Molecular Weight; D009000:Monocytes / Q000737:chemistry*; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D016201:Receptors, Lymphocyte Homing / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*
chemical_list: D002352:Carrier Proteins; D018960:Hyaluronan Receptors; D011956:Receptors, Cell Surface; D016201:Receptors, Lymphocyte Homing; D006820:Hyaluronic Acid