Lymph node macrophage heterogeneity: the phenotypic and functional characterization of two distinct populations of macrophages from rat lymph node.
The isolation and characterization of lymph node macrophages (M phi) has shown a hitherto unknown heterogeneity. Two types of M phi were distinguished by morphology, monoclonal antibody staining and functional assays. The type I M phi failed to express surface Ia even when activated, a characteristic which has only previously been reported for splenic marginal zone M phi; despite studies suggesting an antigen presentation role for the M phi, the failure to express surface Ia would seem to eliminate an interaction with T helper cells for the type I M phi in the lymph node. In contrast, the type I M phi, other characteristics of clustering with activated B cells in vitro, the colocalization of the type I M phi and activated B cells in situ, the specific uptake of thymus-independent type 2 antigens and the failure to undergo respiratory burst activity all suggest a M phi-B cell interaction, possibly of a trophic nature. The defective microbicidal activity of the type I M phi may have been compensated for by the type II M phi, which expresses both strong respiratory burst activity and surface Ia expression when freshly isolated. However, unlike the inflammatory M phi the activated phenotype of the type II M phi did not appear to be interferon-gamma dependent because type II M phi could also be isolated from nude rat lymph nodes.
Chao
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Sir William Dunn School of Pathology, University of Oxford.
MacPherson
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D000818:Animals; D000911:Antibodies, Monoclonal; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology; D001402:B-Lymphocytes / Q000276:immunology; D018801:CD2 Antigens; D002469:Cell Separation; D002478:Cells, Cultured; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D008198:Lymph Nodes / Q000166:cytology*; D008264:Macrophages / Q000145:classification* / Q000502:physiology; D010101:Oxygen Consumption; D010587:Phagocytosis; D051381:Rats; D011919:Rats, Inbred Strains; D011971:Receptors, Immunologic / Q000502:physiology; D013154:Spleen / Q000166:cytology
D000911:Antibodies, Monoclonal; D015214:Antigens, Differentiation, Myelomonocytic; D000945:Antigens, Differentiation, T-Lymphocyte; D018801:CD2 Antigens; D000949:Histocompatibility Antigens Class II; D011971:Receptors, Immunologic