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)

An immunoelectron-microscopic technique was applied to investigate the localization of molecules that are involved in the elicitation of allergic contact dermatitis in human epidermal cells in situ. Langerhans cells in the epidermis of lesions showed a strongly increased cell surface expression of HLA class II molecules as compared with normal skin. In addition, a high number of intracellularly located HLA class II molecules were present in Langerhans cells of lesional epidermis, suggesting increased biosynthesis of these molecules during the elicitation process. In contrast, no differences in the expression of CD1a by Langerhans cells was observed between normal and lesional skin. Frequently, the Langerhans cells were found in close apposition to mononuclear cells, which also exhibited a strong cell surface HLA class II expression. The number of Birbeck granules that are characteristic intracellular Langerhans cells organelles was increased in lesional Langerhans cells as compared with normal-skin Langerhans cells, which may correlate with the activated state of lesional Langerhans cells. These Birbeck granules were always HLA class II or CD1a negative. The increased synthesis and expression of HLA class II molecules on the cell surface of Langerhans cells suggests a direct role for these HLA class II molecules in the elicitation process of allergic contact dermatitis.
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PMID:HLA class II expression on human epidermal Langerhans cells in situ: upregulation during the elicitation of allergic contact dermatitis. 142 38

This report describes the antigenic profile of the proliferating cells of pulmonary histiocytosis X (HX) in a patient treated with chemotherapy for Hodgkin's lymphoma; the association of pulmonary HX and Hodgkin's disease has rarely been described in the literature. The histopathological diagnosis of HX was confirmed with the aid of monoclonal antibodies (mAbs) to CD4, CD1a, and polyclonal serum anti S-100 protein. The phenotype of HX cells has been analysed using a panel of mAbs against HLA class I A, B, C monomorphic determinants, locus A and B, beta 2-microglobulin, HLA class II distinct monomorphic determinants, DP, DQ, DR, intercellular adhesion molecule-1 (ICAM-1) and vitronectin receptors. Our results indicate that HX cells express HLA class I and II, including locus A, locus B and DP, DQ, DR, like their normal counterpart (represented by Langerhans cells) and detectable levels of ICAM-1 but not vitronectin receptors. We would like to stress the possibility of the association of HX and Hodgkin's lymphoma extending the immunophenotypic profile of HX cells.
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PMID:Histiocytosis X arising in Hodgkin's disease: immunophenotypic characterization with a panel of monoclonal antibodies. 170 28

The distribution of HLA class II (DR, DP, DQ) and Fc gamma R (I, II, III) was analyzed in the epithelia of patients with advanced marginal periodontitis using cryostat sections incubated with monoclonal antibodies (MoAb) against the Langerhans cell (LC) (CD1a) and various subtypes of HLA class II and Fc gamma R, and the indirect immunofluorescence technique. In the oral gingival epithelium (OGE), LC were concentrated subjacent to the connective tissue papillae, while in the pocket epithelium (PE), they were most abundant at the gingival margin. HLA-DP, DQ, and DR stained LC in both OGE and PE. HLA-DQ+ LC were significantly fewer than DP+ and DR+ LC. HLA-DR also stained keratinocytes (KC) in the whole extension of both OGE and PE. HLA-DP was also observed on KC, but not HLA-DQ. Fc gamma R II stained both LC and focal areas of KC. In PE FC gamma R II+ LC were concentrated near the bottom of the pocket, while in the OGE, they were concentrated at the gingival margin. Fc gamma R III was present only on KC, especially in the basal and suprabasal layer. The results indicate that the epithelial cells are actively involved in the development and maintenance of the inflammation of periodontal disease.
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PMID:Epithelial expression of HLA class II antigens and Fc gamma receptors in patients with adult periodontitis. 752 33

Birbeck granules (BG) are cytoplasmic organelles that are only found in Langerhans cells (LC). The function of BG is still unclear, although it has been claimed that they are actively involved in receptor-mediated endocytosis and participate in the antigen-processing/presenting function of LC. We have identified a healthy white 29-year-old man whose LC completely lack the presence of BG as determined by electronmicroscopic studies. This was observed repeatedly using skin biopsy specimens taken from several places on the body during a period of 2.5 years. The absence of BG in these LG was documented further by the lack of staining with a BG-specific monoclonal antibody. Despite the complete lack of BG, LC were present in normal numbers, had all the usual morphologic characteristics, and were CD1a and human leukocyte antigen (HLA) class II positive. Two observations indicate that these BG-negative LC display normal antigen-presenting capacity. First, the individual could be sensitized by the hapten diphenylcyclopropenone. This was accompanied by a strong increase in the cell surface expression of HLA class II antigens on his LC, suggesting LC activation. Second, his epidermal cells elicited a normal positive response in an allogeneic mixed epidermal cell lymphocyte reaction. Together these observations strongly suggest that BG are not a prerequisite for normal LC function in vivo and in vitro.
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PMID:Functional human epidermal Langerhans cells that lack Birbeck granules. 779 19

Human dendritic cells (DC) can now be generated in vitro in large numbers by culturing CD34+ hematopoietic progenitors in presence of GM-CSF+TNF alpha for 12 d. The present study demonstrates that cord blood CD34+ HPC indeed differentiate along two independent DC pathways. At early time points (day 5-7) during the culture, two subsets of DC precursors identified by the exclusive expression of CD1a and CD14 emerge independently. Both precursor subsets mature at day 12-14 into DC with typical morphology and phenotype (CD80, CD83, CD86, CD58, high HLA class II). CD1a+ precursors give rise to cells characterized by the expression of Birbeck granules, the Lag antigen and E-cadherin, three markers specifically expressed on Langerhans cells in the epidermis. In contrast, the CD14+ progenitors mature into CD1a+ DC lacking Birbeck granules, E-cadherin, and Lag antigen but expressing CD2, CD9, CD68, and the coagulation factor XIIIa described in dermal dendritic cells. The two mature DC were equally potent in stimulating allogeneic CD45RA+ naive T cells. Interestingly, the CD14+ precursors, but not the CD1a+ precursors, represent bipotent cells that can be induced to differentiate, in response to M-CSF, into macrophage-like cells, lacking accessory function for T cells. Altogether, these results demonstrate that different pathways of DC development exist: the Langerhans cells and the CD14(+)-derived DC related to dermal DC or circulating blood DC. The physiological relevance of these two pathways of DC development is discussed with regard to their potential in vivo counterparts.
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PMID:CD34+ hematopoietic progenitors from human cord blood differentiate along two independent dendritic cell pathways in response to GM-CSF+TNF alpha. 876 Aug 23

We present an immunohistochemical study of accessory cells in acute appendicitis and ulcerative colitis (UC). By comparing these two diseases, it is possible to distinguish between changes associated with inflammatory bowel disease and those resulting from nonspecific intestinal inflammation. Nine total colectomy specimens from patients with UC, in which the appendix was also involved, were compared with nine cases of acute appendicitis. Accessory cells were stained for CD68 (PGMI), ACPI (acid cysteine proteinase inhibitor), S100 protein, MAC387 (calgranulin), CD1a, factor XIIIa, and WR18 (HLA class II). In ulcerative colitis, but not acute appendicitis, there was extension of a network of S100 positive dendritic cells into the crptal mucosa, and these S100-positive dendritic cells were closely aligned with the epithelium. The epithelium in UC, but not in acute appendicitis, showed intense upregulation of HLA class II, and this was particularly marked at the crypt bases. Dendritic, MAC387-positive cells were seen only in UC. In both diseases there were abundant ACPI-positive accessory cells in the cryptal areas, a population normally restricted to the dome areas. Factor XIIIa- and PGM1-positive cells, although abundant in both conditions, had distributions similar to those that we had previously shown in normal controls. No CD1a-positive cells were identified in either UC or acute appendicitis. We hypothesize that S100 identifies a subpopulation of activated macrophages. The concentration of this subpopulation, in close contact with the epithelium, which also shows altered expression of HLA class II antigens, suggests that a component of the immune response is targeting this area in UC. In addition, we also suggest that the identification of MAC387-positive dendritic cells in UC reflects increased macrophage turnover in inflammatory bowel disease.
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PMID:The accessory cell populations in ulcerative colitis: a comparison between the colon and appendix in colitis and acute appendicitis. 904 93

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

Interferon-alpha (IFN-alpha) (IFN-alpha2b) is an immunoregulatory cytokine that is presently used in a recombinant form for the treatment of tumours and chronic viral infection. However, its mechanism of action remains largely undefined. In this paper, we studied the effects of low doses of IFN-alpha (0-100 U/ml) on the generation of dendritic cells with granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-4 (IL-4), and tumour necrosis factor (TNF)-alpha in cultures of human peripheral blood mononuclear cells (PBMCs). An addition of IFN-alpha to the PBMC cultures greatly increased the HLA class II and the CD86 expression on developing dendritic cells (DCs) during a 7-day culture period. When added at the initiation of the PBMC culture, as little as 10 U/ml dramatically increased the HLA class II and CD86 expression, with maximal effects observed between 50 and 100 U/ml in all PBMC preparations tested. Almost all of the nonadherent cells induced with added IFN-alpha possessed a phenotype of mature DCs, being CD1a(low), CD83+, HLA class IIhigh, CD86high, CD40high, and CD80low, while being negative for the monocyte/macrophage and lymphocyte markers. In contrast, the floating cells isolated from cultures grown without IFN-alpha were mostly immature DCs with a CD1a(high), CD83-, HLA class IIint/high, CD86low/int, CD80low phenotype. An addition of 50 U/ml IFN-alpha at the time of the culture initiation greatly increased both the number of mature DCs generated and their rate of appearance; by 3 days of culture, many large floating aggregates were present containing mature CD83+, CD1a(low) DCs, while much fewer aggregates of mature DCs were found without added IFN-alpha. Histochemical staining confirmed that the floating cells induced with IFN-alpha had typical DC features, including irregularly shaped nuclei, few cytoplasmic granules, and absent or diffuse perinuclear staining for esterase. Our results suggest that IFN-alpha is a potent accelerator of DC maturation in vitro. These effects on DC maturation may explain its clinical success in the treatment of cancer and viral infection as well as its ability to promote autoimmunity.
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PMID:Low levels of interferon-alpha induce CD86 (B7.2) expression and accelerates dendritic cell maturation from human peripheral blood mononuclear cells. 1056 53

Dendritic cells (DC) are powerful antigen presenting cells, which have the unique capacity to stimulate naive T cells. In spite of the well-known decline of T cell function in old age, little information is available on whether DC are also affected by the aging process. This is mainly due to problems with the isolation and purification of DC. Rapid progress in the characterization of DC has been made in recent years, as simple methods to generate large numbers of DC from precursors have been developed. It was the aim of the present study to compare monocyte derived DC from old and young healthy persons. The generation of DC from blood monocytes in response to GM-CSF and IL-4 treatment was similar in cells from young and old persons. The DC population thus obtained had a typical dendritic morphology and expressed DC surface markers, such as HLA class II, CD1a, CD11c, CD54, CD80 and CD86, but not CD14 for a period of up to three weeks in culture. DC from young and old persons produced IL-12 and TNF-alpha and responded equally well to maturation-inducing stimuli. DC maturation was stimulated by purified protein derivative (PPD) of Mycobacterium tuberculosis, whole inactivated influenza virus and by influenza split vaccine, but not by purified viral RNA. When tested for their antigen-presenting capacity, DC from young and old persons were capable of stimulating the proliferation and the cytokine production of T cells. It was of particular interest that CD45RA(+) as well as CD45RO(+) T cells from aged donors were unable to respond to stimulation with influenza proteins presented by monocytes, but were triggered to proliferate and to produce cytokines when antigen was presented by DC. The results demonstrate that DC from old persons (a) may still function as powerful antigen-presenting cells provided the right differentiation and maturation stimuli are present; (b) are capable of mobilizing residual capacity in senescent T cells and (c) may therefore represent a potent tool for immunotherapy and vaccines in old age.
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PMID:Unimpaired dendritic cells can be derived from monocytes in old age and can mobilize residual function in senescent T cells. 1068 36

This report is focused on the functional capacity of Langerhans cells (LC) in the epithelium of skin and oral mucosa, which both meet different antigenic challenges. The capacity of LC from human oral and skin epithelium to provide co-stimulatory signals to T cells in vitro was compared. LC in a crude suspension of oral epithelial cells had a significantly enhanced T cell co-stimulatory capacity compared to skin epithelial cells. This applied both to cultures with concanavalin A (con-A)-stimulated syngeneic T cells and to a mixed epithelial cell lymphocyte reaction involving allogeneic T cells. The co-stimulatory capacity of oral and skin epithelial cells was reduced by >70% if monoclonal antibodies against HLA-DR, -DP and -DQ were added to the cultures with allogeneic T cells, indicating the involvement of HLA class II expressing LC. Immunohistochemistry revealed that 6% of the epithelial cells were CD1a + LC in sections from both oral and skin epithelium. Interleukin (IL)-8 production was higher in cultures of oral epithelial cells and con-A stimulated T cells than in corresponding cultures with skin epithelial cells as accessory cells. The results suggest that LC in human oral epithelium are more efficient at stimulating T cells than those of skin.
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PMID:Langerhans cells from human oral epithelium are more effective at stimulating allogeneic T cells in vitro than Langerhans cells from skin. 1514 50


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