MHC class II compartment, endocytosis and phagocytic activity of macrophages and putative dendritic cells isolated from normal tissues rich in synovium.
The endocytic and phagocytic activities of a population of MHC IIhi CD11c+ dendritic cell (DC)-like cells in synovium-rich tissues (SRTs) of normal rat paws were compared with CD163+ cells (putative macrophages) from the same tissues and pseudo-afferent lymph DCs, peritoneal macrophages and blood monocytes. Fifty percent of CD11c+ cells and 75% of CD163+ cells isolated from SRT internalized fluorescein-conjugated dextran (FITC-DX). Of these endocytic cells, half of those expressing CD11c, but only 30% of those expressing CD163, were surface MHC class II+ (sMHC II+). CD11c+ cells were more endocytic than monocytes or pseudo-afferent lymph DC, but some CD163+ cells (type A synoviocytes) were found to be highly endocytic. CD163+ cells from SRT were more phagocytic (25%) than the general MHC class II+ population (16%). Of phagocytic cells, 40% of CD163+ cells were sMHC II(variable) and they constituted 60% of all MHC class II+ phagocytic cells. Only 18% of phagocytic MHC II+ cells expressed CD11c and the most of these were MHC IIhi. In comparison, 60% of CD163+ peritoneal macrophages were phagocytic, while blood monocytes were poorly phagocytic. Intracellular MHC class II-rich compartments (MIIC) were prominent in sMHC IIhi cells in SRT but rare in CD163+ cells. Most MHC IIhi CD11c+ cells did not have a detectable MIIC.
Moghaddami
Mahin
M
Arthritis Research Laboratory, Hanson Institute for Medical Research, Institute of Medical and Veterinary Science, Adelaide, South Australia.
Mayrhofer
Graham
G
Cleland
Leslie G
LG
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D039521:CD11c Antigen / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology*; D004705:Endocytosis; D005260:Female; D005434:Flow Cytometry; D000949:Histocompatibility Antigens Class II / Q000378:metabolism*; D008264:Macrophages / Q000276:immunology*; D018613:Microscopy, Confocal; D009000:Monocytes / Q000166:cytology / Q000276:immunology; D010587:Phagocytosis; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism; D013583:Synovial Membrane / Q000166:cytology* / Q000276:immunology*; D000098902:CD163 Antigen
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D039521:CD11c Antigen; D000098902:CD163 Antigen; D000949:Histocompatibility Antigens Class II; D011956:Receptors, Cell Surface