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)

Recruitment of monocytes into tissues and their differentiation into macrophages or dendritic cells (DCs) depend on the microenvironment of the inflammatory site. Although many factors affecting this process have been identified, the intracellular signaling pathways implicated are poorly understood. We found that cyclic nucleotides regulate certain steps of monocyte differentiation into DCs. Increased levels of the cyclic nucleotides, cAMP or cGMP, inhibit differentiation of CD14(+)/CD1a(low) monocytes into CD14(-)/CD1a(high) DCs. However, DC-specific ICAM-3-grabbing nonintegrin (CD209) up-regulation was not affected by cyclic nucleotides, indicating that DC development was not blocked at the monocyte stage. Interestingly, Ag-presenting function was increased by cyclic nucleotides, as measured by the higher expression of MHC class II, CD86, and an increased ability to stimulate CD4(+) T cell proliferation in allogeneic MLRs. Although cyclic nucleotides do not completely block DC differentiation, they do block the ability of DCs to be induced to mature by LPS. Treatment during DC differentiation with either cAMP or cGMP analogues hampered LPS-induced expression of CD83, DC-LAMP, and CCR7 and the ability of DCs to migrate toward CCL19/macrophage-inflammatory protein 3beta. Interestingly, the induction of a CD16(+) subpopulation of cells was also observed. Thus, signals causing an increase in either cAMP or cGMP levels during monocyte recruitment to inflammatory sites may restrain the activation of acquired immunity by blocking DC development and migration to lymph nodes. At the same time, these signals promote development of an active intermediate cell type having properties between those of macrophages and DCs, which might contribute to the innate immune response in the periphery.
J Immunol 2003 Dec 15
PMID:Cyclic nucleotides promote monocyte differentiation toward a DC-SIGN+ (CD209) intermediate cell and impair differentiation into dendritic cells. 1466 41

Dendritic cells (DCs), the mononuclear cells that initiate immune response, and osteoclasts, the multinucleated bone-resorbing cells, are derived from monocyte/macrophage precursor cells. Granulocyte-macrophage colony-stimulating factor and macrophage colony-stimulating factor (M-CSF) reciprocally regulate the differentiation of both lineages in mice. Using human monocyte-derived DCs generated in vitro, we show that immature DCs transdifferentiate into functional osteoclasts (OCs) in the presence of M-CSF and receptor activator of nuclear factor-kappaB ligand (RANKL). Transdifferentiation operates through fusion of intermediate adherent bipolar fusiform mononuclear cells expressing CD14, CD1a, and RANKL and able to induce RANKL(+) T-cell proliferation. Surprisingly, DC fusion in vitro is faster and more efficient than monocyte fusion to form multinucleated giant cells. The transdifferentiation process reported here supports the existence of a high cellular plasticity within differentiated myeloid phagocytes. Importantly, this process is greatly enhanced by rheumatoid arthritis synovial fluid and involves proinflammatory cytokines such as interleukin 1 or tumor necrosis factor alpha, as well as components of the extracellular matrix such as hyaluronic acid. Our data therefore suggest that DC-derived OCs may be directly involved in the osteolytic lesions observed in human inflammatory bone diseases such as rheumatoid arthritis or in particular forms of Langerhans cell histiocytosis, characterized by accumulation of immature skin DCs and chronic lytic bone lesions.
Blood 2004 Dec 15
PMID:Immature dendritic cell transdifferentiation into osteoclasts: a novel pathway sustained by the rheumatoid arthritis microenvironment. 1530 76

Myelodysplastic syndromes (MDS) are clonal stem cell disorders, characterized by ineffective and dysplastic hematopoiesis. MDS patients have a defective immune response manifested by increased susceptibility to bacterial infections, autoimmune phenomena, and high incidence of lymphoid malignancies. Presently, we investigated the phenotype and function of monocyte-derived dendritic cells (MoDC) in 23 MDS patients and 15 controls at different stages of differentiation using the maturation stimuli tumor necrosis factor-alpha (TNF-alpha) and LPS. Monocytes from MDS patients showed low potential to differentiate into dendritic cells (DC), as determined by low cell yield and CD1a expression. MDS-MoDCs exhibited low expression of mannose receptor and reduced endocytic capacity. MDS-MoDCs showed a diminished response to TNF-alpha with low CD83, CD80, and CD54 expression and allostimulatory capacity. In patients with 5q syndrome, monocytes and MoDCs were positive for the 5q deletion, suggesting their origin from the malignant clone. Our data indicate that MoDCs in MDS display quantitative and functional abnormalities that may contribute to the defective immune response of these patients.
Clin Immunol 2004 Dec
PMID:Defective tumor necrosis factor alpha-induced maturation of monocyte-derived dendritic cells in patients with myelodysplastic syndromes. 1550 96

The distribution of specific histiocyte subsets within the human gastrointestinal tract has not been extensively characterized. Our goal was to immunohistochemically evaluate the distribution and location of CD1a-positive, CD68-positive, and Factor XIIIa (FXIIIa)-positive histiocyte subsets within the normal gastrointestinal tract and attempt to relate distribution to possible function. Twenty-nine samples of normal esophagus, stomach, small bowel, large bowel, and anus were routinely processed and immunohistochemically stained with antibodies to CD68, CD1a, and FXIIIa. The distribution and histologic location of histiocyte subsets were qualitatively analyzed. CD1a-positive cells were seen exclusively within anal and esophageal squamous mucosa. CD68 positive histiocytes were present in lamina propria and submucosa throughout the gastrointestinal tract and in Peyer patches. FXIIIa-positive histiocytes were also abundant in lamina propria and submucosa throughout the gastrointestinal tract, particularly around pericryptal sheaths and in parafollicular regions surrounding Peyer patches. Our results showed that there are distinct subpopulations of gastrointestinal histiocytes, and that distribution varies according to both cell type and site. Because Langerhans cells are epidermal antigen processing/presentation cells, their exclusive presence in squamous mucosa suggests an analogous function there. The prominence of both CD68 and FXIIIa-positive cells surrounding glandular pericryptal sheaths suggests that they are important to immune function at this mucosal interface and may play a role in communication between glands and lamina propria. In addition, the presence of specific histiocyte subsets within Peyer patches and para-follicular regions suggests that they are involved in different aspects of antigen processing associated with gut lymphoid tissue. Further studies are needed to explore the relation between specific histiocyte subsets and gastrointestinal disease processes.
Appl Immunohistochem Mol Morphol 2004 Dec
PMID:Histiocytic subpopulations in the gastrointestinal tract: distribution and possible relationship to function. 1553 37

Erdheim-Chester disease is a rare nonfamilial histiocytic disorder of unknown etiology with characteristic long bone findings. The 3-year survival rate for patients with Erdheim-Chester disease is 50%. Approximately 50% of patients have disease involvement in other tissues, including skin, retro-orbital and periorbital tissues, pituitary-hypothalamic axis, heart, kidney, retroperitoneum, breast, skeletal muscle, and sinonasal mucosa; about 20% of patients have lung involvement. Prognosis generally depends on the extent of the extraosseous disease. For patients with lung involvement, gender distribution is equal, but men typically present at an older age than do women. Approximately 80% of patients present with dyspnea, and most patients have diffuse interstitial infiltrates and pleural and/or interlobar septal thickening on chest radiology. Characteristic lung histopathology includes the accumulation of histiocytes with variable amounts of fibrosis and a variable lymphoplasmacytic infiltrate in a lymphangitic distribution. Immunostains are diagnostically useful, showing immunopositivity for CD68 and factor XIIIa and immunonegativity for CD1a. Birbeck granules are uniformly absent ultrastructurally.
Arch Pathol Lab Med 2004 Dec
PMID:Pulmonary and ophthalmic involvement with Erdheim-Chester disease: a case report and review of the literature. 1557 89

CD1 molecules are expressed by antigen-presenting cells such as dendritic cells and mediate primary immune responses to lipids and glycolipids which have been shown to be expressed by various tumors. Glycolipids are expressed by melanoma cells but, despite their immunogenicity, no efficient spontaneous immune responses are elicited. As IL-10 has previously been shown to down-regulate CD1a on dendritic cells and is known to be expressed by various melanoma cell lines, we investigated if melanoma-derived IL-10 could down-regulate CD1 molecule expression on dendritic cells as a possible way to circumvent immune recognition. We found that CD1a, CD1b, CD1c, and CD1d were significantly down-regulated on dendritic cells in metastatic (n = 10) but not in primary melanoma lesions (n = 10). We further detected significantly higher IL-10 protein levels in metastatic than in primary melanomas. Moreover, supernatants from metastatic melanomas were significantly more effective in down-regulating CD1 molecules on dendritic cells than supernatants from primary melanoma cultures. This effect was blocked using a neutralizing IL-10 antibody in a dose dependent manner. Our findings suggest that metastatic but not primary melanomas can down-regulate CD1 molecules on infiltrating dendritic cells by secreting IL-10 which may represent a novel way to escape the immune response directed against the tumor.
Am J Pathol 2004 Dec
PMID:Metastatic melanoma secreted IL-10 down-regulates CD1 molecules on dendritic cells in metastatic tumor lesions. 1557 30

We have investigated how the maturation of monocyte-derived dendritic cells (Mo-DC) is affected by the serum concentration of the culture medium. Day 6 DC cultured in 1% human serum were a heterogeneous population of CD1a(-) and CD1a(+) DC that were separated by flow sorting. In contrast, Mo-DC generated in 10% human serum formed a homogenous population of CD1a(-) cells. Other phenotypically immature characteristics also varied, and three subsets were still distinguishable upon maturation in LPS. Furthermore, CD1a(-) DC and CD1a(+) DC from 1% culture conditions were excellent stimulators in MLR, while DC cultured in 10% serum were poor stimulators. Similarly, different cytokine profiles of the three subsets were identified. DC cultured in 1% serum had low expression of interleukin-12 (IL-12) p40 and IL-10 mRNA at day 6. Upon maturation, expression of IL-12 p40 mRNA was upregulated in CD1a(+) DC, whereas the level remained relatively low in CD1a(-) DC. In contrast, DC cultured in 10% had high levels of IL-10 mRNA at day 6 that was downregulated upon maturation. We conclude that the differentiation of monocytes into DC is significantly influenced by the serum concentration of the growth medium with effects on phenotype, cytokine profile and stimulatory activity.
Scand J Immunol 2004 Dec
PMID:Serum concentration of the growth medium markedly affects monocyte-derived dendritic cells' phenotype, cytokine production profile and capacities to stimulate in MLR. 1558 69

We investigated the effects of dendritic cell (DC) pulsed with acute leukemia cell frozen-thawed antigen on inducing the cytotoxic T lymphocyte (CTL) to get specific anti-tumor activity in vitro. DC was generated from healthy human bone marrow mononuclear cell (BMMC) in the presence of granulocyte/macrophage-colony stimulating factor(GM-CSF), interleukin-4 (IL-4) in vitro. DC pulsed with acute leukemia cell frozen-thawed antigen was co-cultured to induce T cell into specific CTL. Then we observed the effects of CTL induced by DC pulsed with acute leukemia cell frozen-thawed antigen killing acute leukemia cell specially and the influence of dendritic cell affecting the function and CD expression on CTL. The levels of CD1a, CD86, HLA-DR expression on DC pulsed with acute leukemia cell frozen-thawed antigen were obviously higher than those before culture (P<0.01). There were more CD3+CD8+ T cells in the CTL induced by DC pulsed with acute leukemia cell frozen-thawed antigen, compared with those in the T cell uncultured group (P<0.01). The CTL induced by DC pulsed with acute leukemia cell frozen-thawed antigen significantly had higher activity in killing acute leukemia cell than in killing k562 cell (P<0.01), and the CTL induced by DC pulsed with acute leukemia cell frozen-thawed antigen was also more effective for killing acute leukemia cell as compared with the CTL induced by DC simply, T cell co-cultured with IL-2 and T cell simply (P<0.01). The DC generated from human bone marrow mononuclear cell (BMMC) in the presence of granulocyte/macrophage-colony stimulating factor (GM-CSF), interleukin-4 (IL-4) was CD14- CD1a+CD83+DC, and it could also induce the cytotoxic T lymphocyte (CTL) to get specific anti-tumor activity in vitro. Otherwise,the increasing of CD3+CD8+ T cells in the CTL induced by DC pulsed with acute leukemia cell frozen-thawed antigen implied the main role of the CD3+CD8+ T cells in the anti-tumor immunity.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2004 Dec
PMID:[Investigation on specific killing acute leukemia cell reaction of the cytotoxic T lymphocyte induced by dendritic cell pulsed with frozen-thawed antigen]. 1564 45

Langerhans cell histiocytosis (LCH) is a disorder characterized by neoplastic proliferation of Langerhans cells that rarely involves the skin in adults. A 74-year-old woman presented with a fourteen year history of eosinophilic granuloma and bone involvement caused by LCH. She had received three combination therapy courses of curettage and radiation since 1987 and had remained free of LCH signs for seven years, after which she started to notice brown nodules on her left leg. Biopsy specimens taken from the lesions showed massive proliferations of large histiocytic cells. Immunoperoxidase stainings for CD1a and S-100 protein were positive. Electron microscopy identified Birbeck granules in the cytoplasm of the atypical Langerhans cells. Treatment with oral prednisolone alone has resulted in the patient remaining in complete remission for 12 months.
J Dermatol 2004 Dec
PMID:Langerhans cell histiocytosis involving the skin of an elderly woman: a satisfactory remission with oral prednisolone alone. 1580 Dec 69

Apolipoprotein A-I (apoA-I), the major protein component of serum high-density lipoprotein, exhibits anti-inflammatory activity in atherosclerosis. In this study, we demonstrate that apoA-I inhibits DC differentiation and maturation. DC differentiated from monocytes in the presence of apoA-I showed a decreased expression of surface molecules such as CD1a, CD80, CD86, and HLA-DR. In addition, these DC exhibited decreased endocytic activity and weakened allogeneic T-cell activation. During DC differentiation in the presence of apoA-I, PGE(2) and IL-10, which are known to be DC differentiation inhibitors and/or modulators of DC function, were produced at remarkable rates, whereas IL-12 production in the cells after stimulation with CD40 mAb and IFN-gamma was significantly decreased in comparison with the control DC. T cells stimulated by apoA-I-pretreated DC produced significantly low levels of IFN-gamma, and apoA-I inhibited cross-talk between DC and NK cells, in terms of IL-12 and IFN-gamma production. Therefore, apoA-I appears to play an important role in modulating both innate immune response and inflammatory response. The novel inhibitory function of apoA-I on DC differentiation and function may facilitate the development of new therapeutic interventions in inflammatory diseases.
Biochem Biophys Res Commun 2005 Dec 16
PMID:Apolipoprotein A-I induces IL-10 and PGE2 production in human monocytes and inhibits dendritic cell differentiation and maturation. 1625 56


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