Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06126 (CD1a)
 2,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is well established by in vivo and in vitro studies that dendritic cells (DCs) originate from hematopoietic progenitor cells. However, the presumed intermediate of Birbeck granule (BG)+ Langerhans cells (LCs) has not been detected in cultures derived from bone marrow or peripheral blood progenitor cells (PBPCs), thus contrasting with the data obtained with cord blood. We show here that large numbers of BG+ LCs can be generated from human CD34+ PBPCs in vitro, when granulocyte-macrophage colony-stimulating factor and interleukin-4, potent promotors of LC/DC differentiation, are combined with a cocktail of early acting hematopoietic growth factors. LCs were found to emerge from CD33+CD11b+CD14- progenitor cells that they share with the monocytic lineage. During culture, these cells exhibited a sequence of dramatic morphologic changes, starting with a major increase in granularity followed by an increase in size herein exceeding that of all peripheral blood cells. At the same time, CD1a and major histocompatibility complex class II expression were upregulated and virtually all CD1a++ cells were BG+ by electron microscopy. With prolonged culture, CD1a was downregulated on a major population of cells, paralleled by a loss of BG and an increase of CD4, CD25, and CD80 expression that may correspond to the maturation of epidermal LC in vitro. However, these cells were consistently CD5- and did not exhibit changes in the CD45-isoform expression during culture. The availability of large numbers of these highly purified BG+ LCs and mature DCs allows for specific analysis of these subpopulations and provides a source of potent antigen-presenting cells from individual patients for vaccination protocols against infectious or tumor-associated antigens.
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PMID:Delineation of the dendritic cell lineage by generating large numbers of Birbeck granule-positive Langerhans cells from human peripheral blood progenitor cells in vitro. 754 68

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

Human Langerhans cells (LC) are CD1a+ dendritic cells (DC) that function as potent antigen-presenting cells for primary and secondary immune responses. Limitations in DC/LC numbers, imposed by difficult and tedious isolation procedures, have so far precluded their use as immunogens in the generation and/or augmentation of host responses against various pathogens. Therefore, we have developed a procedure for the generation of human DC/LC from CD34+ hematopoietic progenitor cells (HPC) isolated (mean: 0.7 x 10(6)/ buffy coat and 2.6 x 10(6)/leukapheresis product) and purified ( > 95%) from the peripheral blood of healthy adults. In vitro stimulation of these cells with granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor (TNF)-alpha led to their vigorous proliferation and differentiation resulting in the emergence of CD45+/CD68+/CD3-/CD19-/CD56- leukocytes some of which (mean: 12%) express CD1a and exhibit anti-CD4 and anti-major histocompatibility complex (MHC) class II reactivity. These CD1a- leukocytes include (1) LC as evidenced by the presence of Birbeck granules (BG), (2) CD14+ monocytes, and (3) Birbeck granule-negative cells with a dendritic morphology. Addition of interleukin (IL)-4 to the cytokine cocktail interfered with the development of monocytes and led to a reduction in the overall yield but, on the other hand, resulted in an increased percentage of CD1a+ cells (mean: 24%) among all cells generated. In vitro generated CD1a+, but not CD1a- HPC-derived cells are potent stimulators of the primary mixed leukocyte reaction and, as such, promising candidates for vaccination purposes.
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PMID:Generation of human dendritic cells/Langerhans cells from circulating CD34+ hematopoietic progenitor cells. 860 17

We have previously shown that tumor necrosis factor (TNF)alpha strongly potentiates the granulocyte-macrophage colony-stimulating factor (GM-CSF)/interleukin (IL)-3-dependent proliferation of CD34+ hematopoietic progenitor cells (HPC) through the recruitment of early progenitors with high proliferative potential. Furthermore, the combination of GM-CSF and TNFalpha allows the generation of large numbers of dendritic/Langerhans cells (D-Lc). Herein, we analyzed whether IL-3, when combined to TNFalpha would, as does GM-CSF, allow the generation of CD1a+ D-Lc. Accordingly, cultures of cord blood CD34+ HPC with IL-3 + TNFalpha yielded 20% to 60% CD14+ cells and 11% to 17% CD1a+ cells, while IL-3 alone did not generate significant numbers of CD1a+ cells. Although the percentage of CD1a+ cells detected in IL3 + TNFalpha was lower than that observed in GM-CSF + TNFalpha (42% to 78%), the strong growth induced by IL-3 + TNFalpha generated as many CD1a+ cells as did GM-CSF + TNFalpha. The CD14+ and CD1a+ cells generated with IL-3 + TNFalpha are similar to CD14+ and CD1a+ cells generated in GM-CSF alone and GM-CSF + TNFalpha, respectively. CD1a+ cells differed from CD14+ cells by (1) dendritic morphology, (2) higher expression of CD1a, CD1c, CD4, CD40, adhesion molecules (CD11c, CD54, CD58), major histocompatibility complex (MHC) class II molecules and CD28 ligands (CD80 and CD86), (3) lack of Fc receptor FcgammaRI (CD64) and complement receptor CR1 (CD35) expression, and (4) stronger induction of allogeneic T-cell proliferation. Thus, in combination with TNFalpha, IL-3 is as potent as GM-CSF for the generation of CD1a+ D-Lc from cord blood CD34+ HPC. The dendritic cell inducing ability of IL-3 may explain why mice with inactivated GM-CSF gene display dendritic cells.
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PMID:Interleukin-3 cooperates with tumor necrosis factor alpha for the development of human dendritic/Langerhans cells from cord blood CD34+ hematopoietic progenitor cells. 863 Apr 1

CD34+ precursors in normal human bone marrow (BM) generate large numbers of dendritic cells alongside macrophages and granulocytic precursors when cultured for 12 to 14 days in c-kit ligand, granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF-alpha). This study reports an intermediate cell type that develops by day 6, and has the potential to differentiate into either macrophages or dendritic cells. When the d6 progeny are depleted of mature macrophages and residual CD34+ precursors, a discrete CD14+ HLA-DR+ population persists in addition to immunostimulatory CD14- HLA-DR() dendritic cells. Half of the CD14+ HLA-DR+ population is in cell cycle (Ki-67+), but colony-forming units (CFUs) are no longer detectable. The calls are c-fms+, but lack myeloperoxidase and nonspecific esterase. They also possess substantial phagocytic and allostimulatory activity. These post-CFU, CD14+ HLA-DR+ intermediates develop into typical macrophages when recultured in the absence of exogenous cytokines. M-CSF supports up to approximately 2.5-fold expansion of macrophage progeny. In contrast, the combination of GM-CSF and TNF-alpha supports quantitative differentiation into dendritic cells, lacking c-fms, CD14, and other macrophage properties, and expressing HLA-DR, CD1a, CD83, CD80, CD86, and potent allostimulatory activity. Therefore, normal CD34+ BM precursors can generate a post-CFU bipotential intermediate in the presence of c-kit ligand, GM-CSF, and TNF-alpha. This intermediate cell type will develop along the dendritic cell pathway when macrophages are removed and GM-CSF and TNF-alpha are provided. Alternatively, it can differentiate along a macrophage pathway when recultured with or without M-CSF.
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PMID:Dendritic cells and macrophages can mature independently from a human bone marrow-derived, post-colony-forming unit intermediate. 863 19

It is well established that granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-1 and tumour necrosis factor-alpha (TNF-alpha) are involved in Langerhans' cell (LC) development and dendritic cell traffic. However, little is known about the pattern of cytokine receptors on human LC and their modulation during different stages of maturation. The expression of cytokine receptors was studied by flow cytometry on both freshly isolated LC (fLC) and 72-hr cultured LC (cLC). Epidermal cell suspensions enriched in LC were obtained after skin trypsinization and Ficoll-Hypaque gradient. LC were identified by their CD1a positivity. Although the majority of fLC were positive for the alpha chain of GM-CSF receptor (GM-CSFR), the beta chain of GM-CSFR was detected only on 15% of CD1a+ cells. fLC were also positive for IL-1 receptor (IL-1R) type 1, IL-1R type 2, 75,000 molecular weight TNF receptor (TNFR) and interferon-gamma receptor (IFN-gamma R). IL-6R and its transducing signal gp130 were present in a subset of fLC. Granulocyte colony-stimulating factor receptor (G-CSFR), macrophage colony-stimulating factor receptor (M-CSFR), the alpha and beta chain of IL-2R, IL-4R, IL-7R, IL-8R and 55,000 molecular weight TNFR were not detected on fLC. After culture, LC up-regulated the expression of both the alpha and beta chains of GM-CSFR, IL-1R type 2, alpha and beta chains of IL-2R, IL-6R and gp130. In contrast, IL-1R type 1 and 75,000 molecular weight TNFR were down-modulated and the expression of IFN-gamma R was not affected by culture. These results suggest that LC undergo changes in the cytokine receptor repertory during in vitro maturation.
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PMID:Flow cytometric analysis of cytokine receptors on human Langerhans' cells. Changes observed after short-term culture. 869 97

Recently, we described the isolation through fluorescent-activated cell sorting (FACS) of low autofluorescent (LAF) cells from human bronchoalveolar lavage (BAL). These LAF cells displayed an immunophenotype comparable with that of dendritic cells (DC), and showed a high potency to stimulate naive T cells. In the study reported here we investigated the capability of LAF cells to produce interleukin-1 (IL-1), IL-6, and tumor necrosis factor alpha (TNF-alpha), and the role of these cytokines in allogeneic T-cell stimulation by LAF cells. Lipopolysaccharide (LPS)-stimulated LAF cells released biologically active IL-1, IL-6, and TNF, and also showed intracellular immunoreactivity for IL-1, IL-6, and TNF-alpha. A neutralizing antibody against IL-1 slightly but statistically significantly (P < 0.05, Wilcoxon's test) inhibited the ability of the LAF cells to stimulate allogeneic T-cell proliferation (89% of stimulation in the absence of the antibody). Neutralizing antibodies against IL-6 and TNF-alpha had no effect. An antibody to granulocyte-macrophage colony-stimulating factor (GM-CSF) also interfered with the accessory function of the LAF cells (79% of stimulation in the absence of the antibody, P < 0.05). We also investigated whether subsets of LAF cells (i.e., positive or negative for CD1a and purified by FACS sorting) differed in T-cell stimulatory capacity and in the ability to produce IL-1, IL-6, TNF-alpha, and S100. CD1a+ LAF cells were positive for and produced S100, CD1a- LAF cells were negative in this respect. The CD1a+ subset exhibited a clearly higher and very strong accessory capability as compared with the CD1a- subset. Despite this, CD1a+ LAF cells were poor producers of IL-1, IL-6, and TNF-alpha. The neutralizing antibody to IL-1, however, inhibited the ability of CD1a+ cells to stimulate allogeneic T-cell proliferation (43% of stimulation in the absence of the antibody, P < 0.01). Anti-IL-6 and alpha-GM-CSF had no effects. CD1a- LAF cells were potent producers of IL-1, IL-6, and TNF-alpha, and antibodies to IL-1, IL-6, and GM-CSF strongly interfered with their weaker accessory capability. In conclusion, two different subsets of LAF cells could be identified on the basis of accessory capability and cytokine profile. CD1a+ LAF cells (S100+; very potent T-cell stimulators, poor cytokine producers) are the "Langerhans cells" of the lung. CD1a- LAF cells (S100-; lower T-cell stimulatory capability, potent producers of IL-1, IL-6, and TNF-alpha) displayed a marker pattern intermediate between that of monocytes and monocyte-derived DC.
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PMID:CD1a+ and CD1a- accessory cells from human bronchoalveolar lavage differ in allostimulatory potential and cytokine production. 896 70

We compared dendritic cells (DC) derived from CD34+ hematopoietic progenitor cells with tumor necrosis factor alpha and granulocyte-macrophage colony-stimulating factor (GM-CSF) to DC derived from monocytes/macrophages with interleukin-4 (IL-4) and GM-CSF. Monocyte/macrophage-derived DC demonstrated higher levels of CD1a, lower levels of CD14, greater stimulatory activity in mixed lymphocyte reactions, and greater capacity to present soluble protein antigen than CD34+ cell-derived DC. Lymphocytes stimulated with antigen-pulsed, monocyte/macrophage-derived DC produced more IL-10 than those stimulated with antigen-pulsed, CD34+-derived DC. Whereas CD1a+ DC could be derived from CD34+ cells in serum-free- and human-sera-containing cultures, the derivation of CD1a+ DC from monocytes/macrophages required the presence of fetal calf serum. The spectrum of cytokine mRNA expression, the presentation of peptide antigen, and the sensitivity to human immunodeficiency virus-1 infection of CD34(+)- and monocyte/macrophage-derived DC were comparable. Although cells derived by both methods are potent antigen-presenting cells, there are differences between DC derived in vitro from hematopoietic progenitors and from monocytes/macrophages that may influence their in vivo activity.
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PMID:Phenotypic and functional differences between human dendritic cells derived in vitro from hematopoietic progenitors and from monocytes/macrophages. 912 9

Using a recently described serum-free culture system of purified human CD34+ progenitor cells, we show here a critical cooperation of flt3 ligand (FL) with transforming growth factor-beta1 (TGF-beta1) in the induction of in vitro dendritic cell/Langerhans cell (DC/LC) development. The addition of FL to serum-free cultures of CD34+ cells supplemented with TGF-beta1, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor alpha, and stem cell factor strongly increases both percentages (mean, 36% +/- 5% v 64% +/- 4%; P = .001) and total numbers (4.4- +/- 0.8-fold) of CD1a+ dendritic cells. These in vitro-generated CD1a+ cells molecularly closely resemble a particular type of DC known as an epidermal Langerhans cell. Generation of DC under serum-free conditions was found to strictly require supplementation of culture medium with TGF-beta1. Upon omission of TGF-beta1, percentages of CD1a+ DC decreased (to mean, 10% +/- 8%; P = .001) and, in turn, percentages of granulomonocytic cells (CD1a- cells that are lysozyme [LZ+]; myeloperoxidase [MPO+]; CD14+) increased approximately threefold (P < .05). Furthermore, in the absence of TGF-beta1, FL consistently promotes generation of LZ+, MPO+, and CD14+ cells, but not of CD1a+ cells. Serum-free single-cell cultures set up under identical TGF-beta1- and FL-supplemented culture conditions showed that high percentages of CD34+ cells (mean, 18% +/- 2%; n = 4) give rise to day-10 DC colony formation. The majority of cells in these DC-containing colonies expressed the Langerhans cell/Birbeck granule specific marker molecule Lag. Without TGF-beta1 supplementation, Lag+ colony formation is minimal and formation of monocyte/macrophage-containing colonies predominates. Total cloning efficiency in the absence and presence of TGF-beta1 is virtually identical (mean, 41% +/- 6% v 41% +/- 4%). Thus, FL has the potential to strongly stimulate DC/LC generation, but has a strict requirement for TGF-beta1 to show this costimulatory effect.
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PMID:flt3 ligand in cooperation with transforming growth factor-beta1 potentiates in vitro development of Langerhans-type dendritic cells and allows single-cell dendritic cell cluster formation under serum-free conditions. 926 60

In response to granulocyte-macrophage colony-stimulating factor plus tumor necrosis factor alpha, cord blood CD34+ hematopoietic progenitor cells differentiate along two unrelated dendritic cell (DC) pathways: (1) the Langerhans cells (LCs), which are characterized by the expression of CD1a, Birbeck granules, the Lag antigen, and E cadherin; and (2) CD14+ cell-derived DCs, characterized by the expression of CD1a, CD9, CD68, CD2, and factor XIIIa (Caux et al, J Exp Med 184:695, 1996). The present study investigates the functions of each population. Although the two populations are equally potent in stimulating naive CD45RA cord blood T cells through apparently identical mechanisms, each also displays specific activities. In particular CD14-derived DCs show a potent and long-lasting (from day 8 to day 13) antigen uptake activity (fluorescein isothiocyanate dextran or peroxidase) that is about 10-fold higher than that of CD1a+ cells, which is restricted to the immature stage (day 6). The antigen capture is exclusively mediated by receptors for mannose polymers. The high efficiency of antigen capture of CD14-derived cells is coregulated with the expression of nonspecific esterase activity, a tracer of lysosomial compartment. In contrast, the CD1a+ population never expresses nonspecific esterase activity. The most striking difference is the unique capacity of CD14-derived DCs to induce naive B cells to differentiate into IgM-secreting cells, in response to CD40 triggering and interleukin-2. Thus, although the two populations can allow T-cell priming, initiation of humoral responses might be preferentially regulated by the CD14-derived DCs. Altogether, those results show that different pathways of DC development might exist in vivo: (1) the LC type, which might be mainly involved in cellular immune responses, and (2) the CD14-derived DC related to dermal DCs or circulating blood DCs, which could be involved in humoral immune responses.
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PMID:CD34+ hematopoietic progenitors from human cord blood differentiate along two independent dendritic cell pathways in response to granulocyte-macrophage colony-stimulating factor plus tumor necrosis factor alpha: II. Functional analysis. 926 63


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