title: Monoclonal antibody EBM11 (anti-CD68) discriminates between dendritic cells and macrophages after short-term culture.
abstract: Identification of dendritic cells (DC) is usually done on the basis of their strong MHC class II expression, their typical dendritic morphology and their capacity to induce a strong proliferation of allogeneic T cells. However using these criteria DC can easily be confused with MHC class II positive macrophages (M phi). In addition, the lack of an antibody directed to a specific DC marker greatly hampers the discrimination between DC and M phi. In the present study it is shown that EBM11 (anti-CD68) is a marker specific for both human M phi and DC but in a distinctive way. Human DC locate the EBM11 reactivity in a discrete juxtanuclear spot in contrast to M phi which show EBM11 reactivity throughout the cytoplasm. This greatly improves identification of DC. Light and electron microscopy showed that the CD68 epitope is associated with (phago-)lysosomes. Remarkably the EBM11 spot was only seen in DC after short-term culture, which is an essential step in all classical DC enrichment procedures. Before culture, M phi and DC were indistinguishable. These results show the close relationship between M phi and DC and suggest an important role for the structure of the lysosomal apparatus in these antigen-presenting cells.
authors.affiliation: Department of Cell Biology, Free University, Amsterdam, The Netherlands.
authors.forename: M G
authors.initials: MG
authors.lastname: Betjes
authors.forename: M C
authors.initials: MC
authors.lastname: Haks
authors.forename: C W
authors.initials: CW
authors.lastname: Tuk
authors.forename: R H
authors.initials: RH
authors.lastname: Beelen
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology*; D001202:Ascitic Fluid / Q000276:immunology; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D007959:Lymphocyte Culture Test, Mixed; D008264:Macrophages / Q000276:immunology*; D008853:Microscopy; D016253:Microscopy, Immunoelectron
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD