title: Generation of dendritic cell-like antigen-presenting cells in long-term mixed leucocyte culture: phenotypic and functional studies.
abstract: The mechanisms contributing to the proliferation and differentiation of antigen-presenting cell (APC) precursors upon antigen stimulation or tissue injury are poorly understood. Herein, we report the induction of a population of dendritic cell-like cells (DLC) with potent antigen-presentation function from unfractionated spleen cells by means of repetitive allostimulation in long-term mixed leucocyte cultures (LT-MLC). Initially, only a few adherent DLC were observed. By 4-6 weeks, however, there were large numbers of DLC which survived persistently. Features of these DLC are closely related to dendritic cells (DC), including (1) dendritic, veiled or spiny-processed morphology; (2) expression of a wide array of leucocyte surface markers including DC-associated or restricted antigens: 33D1, NLDC-145, CD11c (N418), heat-stable antigen (HSA), CD44, B7-1 and B7-2; (3) ability to migrate to draining lymph nodes and white pulp area of spleen; (4) expression of high level of major histocompatability complex (MHC) class II molecules and (5) more potent mixed leucocyte reaction (MLR)-stimulating capacity than peritoneal macrophages and APC-enriched spleen cells. DLC-stimulated MLR was inhibited by monoclonal antibodies (mAbs) to B7-1, B7-2, intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), leucocyte-function associated antigen-1 (LFA-1) or very-late activation antigen-4 (VLA-4) by 30-55%. When maintained for more than 2 months, the DLC did not lose their MLR-stimulating activity, but many surface markers were down-regulated except for Mac-2 and VCAM-1, which remained stable or were up-regulated, respectively. In short-term culture, the addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin (IL)-2 enhanced proliferation of DLC, while tumour necrosis factor-alpha (TNF-alpha) and IL-4 did not. IL-4 suppressed not only 'spontaneous', but also GM-CSF-enhanced proliferation, suggesting that cytokines play a differential role in DLC proliferation. These results confirm that professional APC can proliferate in response to repetitive antigen stimulation, and their proliferation is differentially regulated by cytokines. A comparison study of DLC with typical DC is being carried out in our laboratory.
authors.affiliation: Department of Surgery, University of Western Ontario, London, Canada.
authors.forename: J X
authors.initials: JX
authors.lastname: Gao
authors.forename: J
authors.initials: J
authors.lastname: Madrenas
authors.forename: W
authors.initials: W
authors.lastname: Zeng
authors.forename: R
authors.initials: R
authors.lastname: Zhong
authors.forename: D
authors.initials: D
authors.lastname: Grant
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D002455:Cell Division / Q000276:immunology; D002465:Cell Movement / Q000276:immunology; D002469:Cell Separation; D016207:Cytokines / Q000276:immunology; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000648:ultrastructure; D005434:Flow Cytometry; D016130:Immunophenotyping; D007519:Isoantigens / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D008221:Lymphoid Tissue / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL
chemical_list: D016207:Cytokines; D007519:Isoantigens