Heterogeneity of freshly isolated human tonsil dendritic cells demonstrated by intracellular markers, phagocytosis, and membrane dye transfer.
BACKGROUND
Heterogeneity within human dendritic cells (DCs) has been described but its functional relationships to cells of macrophage lineage and its role in human immunodeficiency virus (HIV) infection in vivo remain unclear.


METHODS
Tonsil macrophages and DCs were isolated from low-density cells by negative selection and DCs were sorted into myeloid and plasmacytoid populations using antibodies to CD11c or CD123. Phagocytosis of latex beads and uptake of dye-labeled target cells were compared by flow cytometry and CD68 and S-100 by immunofluorescence on cytospins of sorted cells.


RESULTS
Bead uptake and membrane dye transfer were found in both blood and tonsil CD11c(+) DCs and in CD14(+) cells particularly from blood monocytes. CD11c(-) DCs were poorly phagocytic but took up fluorescent dye from intact, necrotic or apoptotic cells. Tonsil DCs and macrophages expressed both CD68 and S-100 but CD11c(-) DCs expressed CD68 only.


CONCLUSIONS
Freshly isolated CD11c(+) tonsil DCs are similar to CD14(+) macrophages in phagocytic function but the poorly phagocytic CD11c(-) DCs can also take up membrane from target cells. The intracellular markers commonly used to identify DCs and macrophages in situ do not identify accurately the CD11c(-) DC subset nor do they distinguish tonsil macrophages from DCs.
Stent
Gianna
G
Department of Microbiology and Immunology, University of Melbourne, Grattan Street, Parkville, Australia.
Reece
Jeanette C
JC
Baylis
Dean C
DC
Ivinson
Karen
K
Paukovics
Geza
G
Thomson
Megan
M
Cameron
Paul U
PU
D015703:Antigens, CD / Q000378:metabolism; D015415:Biomarkers; D021961:Cell Membrane Structures / Q000378:metabolism; D002648:Child; D003713:Dendritic Cells / Q000145:classification / Q000166:cytology* / Q000378:metabolism; D005434:Flow Cytometry / Q000379:methods; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008264:Macrophages / Q000145:classification / Q000166:cytology / Q000378:metabolism; D014066:Palatine Tonsil / Q000166:cytology* / Q000378:metabolism; D010587:Phagocytosis; D010641:Phenotype
D015703:Antigens, CD; D015415:Biomarkers; D016650:Fluorescein-5-isothiocyanate