title: Peroxidase-positive mononuclear leukocytes as possible precursors of human dendritic reticulum cells.
abstract: In this report, we provide evidence that suggests the dendritic reticulum cells (DRC) occurring in germinal centers of lymphatic follicles originate from a distinct endogenous peroxidase-positive mononuclear blood cell subset. The new monoclonal antibody Ki-M4 showed a highly restricted reactivity, tested by immune histochemistry, being confined to DRC, lining cells of lymph node sinuses, and to 0.001% of nonadherent mononuclear blood cells separated at a density of 1.077 g/ml; the latter exhibited endogenous peroxidase activity in cytoplasmic granules. Such granules being specific for myelomonocytic cells implies that DRC may derive from a committed nonadherent subpopulation of this cell line, which in turn originates from bone marrow. The Ki-M4-reactive antigen was found to be destroyed by the majority of fixatives and to resist 4% paraformaldehyde for 10 min and cold acetone for 30 sec. In cell suspensions from human tonsils, Ki-M4 showed strong reactivity with the outer surface of DRC plasma membrane. This observation demonstrates the possibility of using Ki-M4 to separate DRC from cell suspensions in functional tests.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000937:Antigen-Antibody Reactions; D002454:Cell Differentiation; D005260:Female; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology / Q000648:ultrastructure; D006651:Histocytochemistry; D007124:Immunoenzyme Techniques; D007962:Leukocytes / Q000166:cytology* / Q000201:enzymology / Q000276:immunology; D008221:Lymphoid Tissue / Q000166:cytology* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009000:Monocytes / Q000166:cytology / Q000276:immunology / Q000648:ultrastructure; D014066:Palatine Tonsil / Q000166:cytology / Q000276:immunology / Q000648:ultrastructure
chemical_list: D000911:Antibodies, Monoclonal