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Query: UNIPROT:P06126 (CD1a)
 2,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Colonies of CD1a+ HLA-DR+/DQ+ CD4+ cells with the functional and some of the structural attributes of Langerhans cells are observed in human bone marrow cultures in semi-solid media and are assumed to be the progeny of an early progenitor, the dendritic/Langerhans cell CFU (CFU-DL). The cytokine-regulated growth of these cells has been studied using a chemically defined serum-free system to culture both unfractionated and highly enriched bone marrow progenitor cell populations. Although unfractionated cell growth was optimal in serum replete cultures with PHA-stimulated leukocyte-conditioned medium (PHA-LCM) suboptimal proliferation of CFU-DL was observed in serum even in the absence of PHA-LCM. No colonies were observed under serum-free conditions when granulocyte-macrophage CSF (GM-CSF), IL-3, granulocyte CSF (G-CSF), and macrophage CSF (M-CSF) were present at levels optimal for granulocyte colony-forming unit (CFU-G) and macrophage colony-forming unit (CFU-M) growth. Addition of IL-1 alpha to these cytokines stimulated a small number of CFU-DL. However, in the presence of GM-CSF and IL-3, TNF-alpha or TNF-beta (5 U/ml) were both highly effective in promoting growth up to 82% of optimal and CFU-G growth was also enhanced at these concentrations. TNF was only active during the first 3 days of culture and higher concentrations of TNF-alpha but not TNF-beta were inhibitory for both CFU-DL and CFU-G. CD34+ cell-enriched populations were also enriched for both myeloid progenitors (CFU-G + CFU-M) and CFU-DL to 36- and 48-fold, respectively, and single cell cultures of CD34+ cells yielded single colonies containing both CD1a+ dendritic cells and CD1a- macrophages. Thus dendritic/Langerhans progenitors in the bone marrow expresses CD34, have a capacity for both macrophage and dendritic cell differentiation, and depend on hemopoietic growth factors and TNF for their further development in vitro.
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PMID:Interactions of tumor necrosis factor with granulocyte-macrophage colony-stimulating factor and other cytokines in the regulation of dendritic cell growth in vitro from early bipotent CD34+ progenitors in human bone marrow. 138 22

Langerhans cells (LC) undergo a variety of phenotypic and functional changes in vitro. To determine the effects of granulocyte macrophage--colony-stimulating factor (GM-CSF), tumor necrosis factor-alpha (TNF-alpha), and interleukin 1-alpha (IL-1) on LC phenotype in vitro, epidermal cell suspensions were enriched for LC by density-gradient centrifugation and cultured in the presence of 10 ng/ml of these cytokines. The percentage of cells expressing the surface protein CD1a was determined by flow cytometry. This percentage typically dropped after 48 h culture in both control and cytokine-treated medium to less than half that of the starting value. By the fifth day, the percentage of cells expressing CD1a in TNF-alpha and IL-1--treated cultures was still near half of the starting value, slightly above that of control cultures. Treatment with GM-CSF caused large and consistent decreases in the percentage of epidermal cells expressing CD1a. Cell viability in each of the three cytokine-treated cultures was identical to the control cultures, with essentially all cells having died by the sixth day after isolation. To determine the functional effects of these cytokines, the cytokine-containing medium was replaced after 72 h with medium containing purified allogeneic T cells and proliferation measured. Preliminary experiments showed no increased proliferation induced by IL-1 or TNF-alpha--treated epidermal cells. GM-CSF-treated epidermal cells induced 2-3 times more T-cell proliferation than epidermal cells cultured without additional cytokines. We conclude that GM-CSF, a cytokine known to be produced by keratinocytes in vitro, decreases CD1a expression by human LC and increases their ability to stimulate proliferation by allogeneic T cells.
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PMID:Granulocyte macrophage--colony-stimulating factor (GM-CSF) decreases CD1a expression by human Langerhans cells and increases proliferation in the mixed epidermal cell-lymphocyte reaction (MELR). 169 5

Langerhans' cell histiocytosis (LCH) is characterized by the proliferation of large mononucleated cells containing Birbeck granules and expressing CD1a. Recent studies have demonstrated that LCH is a clonal proliferation; however, its aetiology is still unknown. Growth and differentiation of bone-marrow-derived cells are controlled by cytokines. The proliferation, differentiation and activation of normal Langerhans cells are controlled by granulocyte/macrophage colony-stimulating factor (GM-CSF) in vitro. Therefore, GM-CSF could be implicated in the pathogenesis of LCH. Indeed, LCH cells contain GM-CSF, and children with disseminated LCH have an elevated GM-CSF serum level. As a cytokine only acts on cells expressing a specific receptor, we investigated the presence of GM-CSF receptor on LCH cells. Fourteen frozen tissue samples from children with LCH were studied by in situ immunohistochemistry with two mouse monoclonal antibodies specific for the alpha chain of the GM-CSF receptor (CDw116). LCH cells of all the samples were positively stained with both antibodies. This study suggests that GM-CSF may be a growth factor for LCH cells.
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PMID:Expression of GM-CSF receptor by Langerhans' cell histiocytosis cells. 758 41

The possibility that production of some cytokines in the carcinoma microenvironment is associated with the presence and differentiation of cells belonging to the dendritic cell (DC)/Langerhans' cell (LC) lineage was investigated. Immunohistochemical examination showed the presence of intraepithelial LCs (CD1a- and S100-positive cells) in 6 of 10 squamous cell carcinomas and in 8 of 10 adenocarcinomas. Langerhans' cells were mainly located close to lymphoid aggregates. In situ hybridization performed in four cases (three LC positive and one LC negative) of squamous cell carcinoma and in five cases (four LC positive and one LC negative) of adenocarcinoma showed that some mononuclear cells in the interstitium displayed hybridization with granulocyte macrophage-colony stimulating factor (GM-CSF), tumor necrosis factor-alpha (TNF alpha), and interleukin 1-beta (IL1 beta) cDNA probes. Only in LC-positive carcinomas did epithelial cells close to lymphoid aggregates display small amounts of GM-CSF and TNF alpha mRNA expression. Immunohistochemical analysis performed in the 20 cases of lung carcinoma showed that epithelial cells in tumors with lymphoid aggregates and LCs were immunoreactive with antihuman GM-CSF monoclonal antibody. Specimens negative for GM-CSF contained very few LCs. Northern blot analysis was used to investigate GM-CSF, TNF alpha, IL1 alpha, and IL1 beta mRNA expression in six human lung carcinoma cell lines. A constitutive expression of TNF alpha mRNA was found in all of them, whereas only three showed a low constitutive expression of GM-CSF mRNA. In the latter three cell lines treatment with phytohemagglutinin (PHA)-stimulated peripheral blood lymphocyte (PBL) supernatant (PHA-SUP) upregulated GM-CSF mRNA expression and induced that of IL1 alpha mRNA. Carcinomatous epithelial cells producing small amounts of cytokines could promote the recruitment of cells of DC/LC lineage. Subcellular factors produced by reactive lymphocytes and/or macrophages may influence the production of GM-CSF and IL1 alpha by various epithelia. Up-regulation of this production could favor the arrival and differentiation of DCs and activate LC functions.
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PMID:Role of cytokines in distribution and differentiation of dendritic cell/Langerhans' cell lineage in human primary carcinomas of the lung. 763 48

In this paper we demonstrate that granulocyte-macrophage CSF (GM-CSF) specifically induces the expression of CD1 molecules, CD1a, CD1b and CD1c, upon human monocytes. CD1 molecules appeared upon monocytes on day 1 of stimulation with rGM-CSF, and expression was up-regulated until day 3. Monocytes cultured in the presence of LPS, FMLP, PMA, recombinant granulocyte-CSF, rIFN-gamma, rTNF-alpha, rIL-1 alpha, rIL-1 beta, and rIL-6 remained negative. The induction of CD1 molecules by rGM-CSF was restricted to monocytes, since no such effect was observed upon peripheral blood granulocytes, PBL, and the myeloid cell lines Monomac1, Monomac6, MV4/11, HL60, U937, THP1, KG1, and KG1A. CD1a mRNA was detectable in rGM-CSF-induced monocytes but not in those freshly isolated. SDS-PAGE and immunoblotting analyses of CD1a mAb VIT6 immunoprecipitate from lysate of rGM-CSF-activated monocytes revealed an appropriate CD1a polypeptide band of 49 kDa associated with beta 2-microglobulin. Expression of CD1 molecules on monocytes complements the distribution of these structures on accessory cells, and their specific induction by GM-CSF strengthens the suggestion that CD1 is a family of crucial structures required for interaction between accessory cells and T cells.
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PMID:CD1 molecule expression on human monocytes induced by granulocyte-macrophage colony-stimulating factor. 767 76

The skin is not only a physico-mechanical barrier between the environment and the body, but it also functions as an immune organ. The immunological function of epidermis is principally linked to the presence in this tissue of a distinct subpopulation of dendritic cells: the Langerhans cells (LC). LC constitute 2-4% of epidermal cell population and within epidermis they are the only cells which express MHC class II antigens constitutively. LC play a key role in the initiation of T cell responses to cutaneous antigens by picking up the antigen and migrating to the draining lymph node where they trigger specific T cell activation. There is also evidence that keratinocytes participate in immune responses in the skin since these cells produce a wide variety of cytokines that can modulate T cell responses. Dendritic cells comprise a system of highly efficient antigen-presenting cells which initiate immune responses such as the sensitization of T cells restricted by major histocompatibility complex molecules, the rejection of organ transplants and the formation of T-cell-dependent antibodies. Dendritic cells are found in many non-lymphoid tissues, such as skin and mucosa (Langerhans cells), and they migrate after antigen capture through the afferent lymph or the bloodstream to lymphoid organs, where they efficiently present antigen to T cells. Dendritic cells are difficult to isolate and, although they originate from bone marrow their growth and differentiation are still poorly characterized. Granulocyte macrophage-colony stimulating factor (GM-CSF) favours the out-growth of dendritic cells from mouse peripheral blood. The cooperation between GM-CSF and tumour necrosis factor-alpha (TNF-alpha) is crucial for the generation of human dendritic/Langerhans cells from CD34+ haematopoietic progenitors. The availability of large numbers of these cells should now facilitate the understanding of their role in immunological regulation and disorder. Recent studies reported that after 2-3 days in vitro incubation, both murine and human LC undergo profound phenotypic changes, as an enhancement in the expression of MHC class I and II antigens, LFA-3 and ICAM-1 molecules, a concomitant decrease of CD1a antigens and a loss of Fc gamma RII. Furthermore, cultured LC (cLC) lose or markedly reduce their specific cytoplasmic organelles: the Birbeck granules. Therefore, after a 2-3 days in vitro incubation, LC seem to acquire most of the features of lymphoid dendritic cells.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Cutaneous immune system]. 783 4

Dendritic cells (DC) are the most potent APCs within the immune system. We show here that highly purified CD14(bright) peripheral blood monocytes supplemented with granulocyte-monocyte (GM)-CSF plus IL-4 develop with high efficacy (>95% of input cells) into DC. They neo-expressed CD1a, CD1b, CD1c, CD80, and CD5; they massively up-regulated CD40 (109-fold) and HLA-DQ and DP (125- and 87-fold); and significantly (>5-fold) up-regulated HLA-DR, CD4, CD11b, CD11c, CD43, CD45, CD45R0, CD54, CD58, and CD59. CD14, CD15s, CD64, and CDw65 molecules were down-regulated to background levels, and no major changes were observed for HLA class I, CD11a, CD32, CD33, CD48, CD50, CD86, CDw92, CD93, or CD97. Monocytes cultured in parallel with GM-CSF plus TNF-alpha were more heterogeneous in expression densities but otherwise similar in their surface molecule repertoire. They clearly differed, however, in their accessory cell capacity. Only GM-CSF plus IL-4-cultured cells were found to be potent stimulators in allogeneic and autologous MLR and they presented tetanus toxoid 100- to 1000-fold more efficiently than other cell populations tested. Furthermore, only cytokine-treated monocytes formed clusters with resting T cells. At variance from all these similarities between in vitro-generated monocyte-derived DC and in vivo-developing DC, the DC populations generated by us contained significant amounts of myeloperoxidase and also expressed lysozyme. At least in this respect they, thus, differ from "classical" DC types.
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PMID:Molecular and functional characteristics of dendritic cells generated from highly purified CD14+ peripheral blood monocytes. 889 15

Since either macrophages (Mphi) or dendritic cells (DC) differentiate from monocytes (MO) depending on culture conditions, we investigated the relationship of the DC and Mphi differentiation pathways. Culturing MO-enriched blood mononuclear cells with Mphi colony-stimulating factor (M-CSF) or with granulocyte/Mphi (GM)-CSF induced Mphi with a different morphology and CD14/CD1a expression. In contrast, in cultures with GM-CSF and interleukin (IL)-4, cells rapidly became nonadherent and acquired DC morphology, ultrastructure, CD1a expression, and most DC markers; they lost membrane CD14 and CD64 and capacity of phagocytosis, displayed less CD68 than Mphi, but retained nonspecific esterase activity. These DC directly developed from MO without proliferation inasmuch as only day 0 FACS-sorted MO, but not small CD14- cells, differentiated into DC when cultured with GM-CSF and IL-4, or to Mphi with M-CSF While overall cell numbers declined, DC numbers plateaued from culture day 2 onwards, indicating that most had differentiasted by then. This differentiation was radioresistant and occurred without [3H]thymidine incorporation. Commitment to differentiate into DC with GM-CSF and IL-4 was irreversible by day 2, since discontinuing IL-4 at this point did not revert cells to Mphi. Alternatively, cells rapidly converted to DC when IL-4 was added from day 2 to cultures initiated with GM-CSF only. If cultures were initiated with M-CSF and switched to GM-CSF and IL-4 after 2 or 5 days, about half of the cells still converted to DC. Thus, the capacity of MO and even of Mphi to differentiate into DC was conserved for at least this period. The increased capacity to stimulate the mixed leukocyte reaction correlated with the relative number of CD1a+ cells at any time and under each condition tested, a confirmation that these cells functionally qualify as DC. Thus, MO and even Mphi can be directed to differentiate into DC depending on the cytokine microenvironment.
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PMID:Differentiation of human dendritic cells from monocytes in vitro. 904 14

We evaluated the effects of interleukin (IL)-10 on the differentiation of dendritic cells (DC) obtained by culturing plastic-adherent peripheral blood mononuclear cells for 7 days in presence of granulocyte/macrophage-colony-stimulating factor (GM-CSF) + IL-4. The addition of IL-10 at the initiation of culture resulted in the generation of macrophage-like cells with expressing high levels of CD14 and decreased levels of CD1a and CD1c. Furthermore, cells generated in presence of IL-10 secreted lower levels of IL-12, but higher levels of IL-8 compared with DC generated in absence of IL-10, both spontaneously and after CD40 engagement. Finally, cells generated in presence of IL-10 were less efficient than DC in stimulating the production of IL-2, interferon-gamma, and IL-4 by allogeneic T cells. We conclude that IL-10 prevents the generation of DC induced by GM-CSF + IL-4 and favors the development of macrophages with a lower T cell stimulatory potential, but secreting higher levels of IL-8 than DC.
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PMID:Interleukin-10 prevents the generation of dendritic cells from human peripheral blood mononuclear cells cultured with interleukin-4 and granulocyte/macrophage-colony-stimulating factor. 907 19

Monocytes and dendritic cells are infected by HIV-1 and subsequently produce virions that initiate further rounds of infection. Current methods for the isolation and study of dendritic cells are hampered by the low frequency of these cells and contamination with other cell types. A two-step culture method was devised to generate large numbers of either dendritic cells or monocytes from fetal liver CD34+ progenitors. CD34+ cells were first expanded with the growth factors granulocyte-macrophage CSF and stem cell factor to generate a population of intermediate progenitor cells with a relatively immature phenotype. To induce specific differentiation to dendritic cells, the cultures were switched to serum-free medium with the growth factors granulocyte-macrophage CSF, stem cell factor, TNF-alpha, and IL-4. The cells became highly positive for HLA class II Ags and the dendritic cell marker CD1a. Culture of the intermediate progenitors in serum-containing medium with macrophage CSF resulted in differentiation to adherent monocytes expressing high levels of CD14 with low CD1a expression. The intermediate progenitors were permissive for HIV infection by both monocyte- and lymphocyte-tropic strains. In contrast, differentiation to monocytes or dendritic cells resulted in restricted viral tropism. Dendritic cells efficiently replicated the lymphocyte-tropic virus HIV-1MN, but not the monocyte-tropic virus HIV-1ADA. As expected, monocytes only supported replication of HIV-1ADA. This two-step culture method allows for the production of large numbers of monocytes or dendritic cells from a common precursor pool for studying the development of tropism-associated events.
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PMID:Differential infection of CD34+ cell-derived dendritic cells and monocytes with lymphocyte-tropic and monocyte-tropic HIV-1 strains. 914 24


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