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)

Morphology, phenotype, and enzyme activity of highly enriched (80%) unlabeled human epidermal Langerhans cells (LC) have been studied, with emphasis on changes during a short-term culture of three days in vitro. All freshly isolated LC contained Birbeck granules and expressed high levels of CD1a, CD1c, and MHC class II molecules HLA-DR, -DP, and -DQ. They have a weak to moderate expression of RFD1, C3biR, Fc gamma R, p 150/95, MHC class I molecules HLA-ABC, and of the adhesion molecules LFA-3 and ICAM-1, whereas no expression of LFA-1 and several monocyte/macrophage markers were detected. Human LC undergo profound changes during in vitro culture. Birbeck granules, C3biR, Fc gamma R, and p 150/95 were completely lost and the expression of CD1a and CD1c was markedly decreased or lost. Expression of molecules that have essential functions in antigen presentation remained present at the same level (MHC class II molecules and ICAM-1) or was markedly enhanced (LFA-3 and MHC class I). Highly remarkable was the dramatically enhanced expression of interdigitating cell marker RFD1. The monocyte/macrophage markers initially absent remained absent and the enzyme activity initially present (including ATPase and nonspecific esterase) remained present. In conclusion, the results in this report stress rapid alterations of human LC during in vitro culture, resulting in transformation into cells that have phenotypical characteristics of potent antigen presenting cells that resemble interdigitating cells.
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PMID:Human epidermal Langerhans cells undergo profound morphologic and phenotypical changes during in vitro culture. 240 65

The expression of HLA-DR and CD1 (T6) by Langerhans cells (LC) in human buccal mucosa and skin was investigated with the monoclonal antibodies YE2/36HLK (HLA-DR) and HTA1-C1 (CD1). A five-stage sequential double immunofluorescent-labelling technique, with rhodamine and fluorescein as the fluorochromes, was used to visualize the two surface antigens in the same microscope field. The majority of LC in cryostat sections of buccal mucosa and skin expressed both HLA-DR and CD1.
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PMID:Dual expression of the cell-surface antigens HLA-DR and CD1 (T6) by Langerhans cells in human buccal mucosa and skin. 245 27

Langerhans cells (LC) are dendritic epidermal antigen-presenting cells expressing the surface molecule CD4, which renders them theoretical cellular targets for direct infection by the human immunodeficiency virus (HIV). To date, somewhat conflicting results have been reported concerning the in vivo infection of LC by HIV as well as the numerical alteration of these cells in the course of HIV infection. In the present work we studied clinically normal skin of a group of 44 HIV-1-seropositive patients classified according to the Centers for Disease Control (CDC) stages II (n = 14), III (n = 9), and IV (n = 21). Monoclonal antibodies (MAb) to HIV p18, p24, and gp120 and to HLA-DR and CD1a antigens (specific for LC) were applied on frozen skin sections using an amplification biotin-streptavidin-fluorescein technique. The MAb to HIV p18 cross-reacted with a cytoplasmic antigen of epidermal basal keratinocytes also present on HIV-seronegative skin specimens. No other reactivity was observed with any of the three anti-HIV MAb. The quantitative study showed that no significant correlations could be established between the number of LC (evaluated independently by HLA-DR and CD1a antigens) and the number of peripheral blood CD4+ve lymphocytes or the CDC disease stage. These results cast some doubt on the previously reported in vivo infection and numerical decrease in LC in HIV infection. The precise involvement of LC in HIV infection awaits further investigation.
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PMID:Immunohistochemical study of normal skin of HIV-1-infected patients shows no evidence of infection of epidermal Langerhans cells by HIV. 247 43

Apparently normal, and lesional skin from patients with atopic eczema were investigated immunohistochemically with anti-HLA-DR, -CD1a and -IgE antisera. A CD1a+ intercellular pattern was observed in uninvolved skin in the majority of the patients whereas an HLA-DR+/CD1a+ network, mostly localized in basal and supra-basal areas, was shown in lesional skin of virtually all of them. Moreover, an HLA-DR+/CD1a+IgE+ intercellular pattern was observed in some of the patients only and was predominantly localized in those areas characterized by lymphocyte exocytosis, spongiosis or vesicle formation. Whether keratinocytes are able to synthesize CD1a antigen and Fc epsilon R or if these molecules are only produced and shed by CD1a+/IgE+ epidermal dendritic cells remains unclear.
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PMID:Keratinocytes in lesional skin of atopic eczema bear HLA-DR, CD1a and IgE molecules. 247 18

Topical corticosteroids decrease the number of HLA-DR+T6+ Langerhans cells (LCs) and the antigen-presenting capacity of epidermal cells (ECs). We have investigated the properties of residual HLA-DR+T6+ LCs in steroid-treated human skin. Flow cytometric analysis revealed that clobetasol propionate 0.05% applied twice daily for 7 d reduced the percentage of HLA-DR+T6+ LCs in EC suspensions to 46% of control (from a mean percentage +/- sem of 2.49 +/- 0.30 in control skin to 1.15 +/- 0.22 in steroid-treated skin), but did not significantly alter the relative amounts of HLA-DR and CD1a/T6 antigens per individual HLA-DR+T6+ cell. HLA-DR+T6- and HLA-DR-T6+ cells were not detected in either group. Steroid therapy significantly decreased the allostimulatory capacity of unsorted ECs. By contrast, in parallel experiments in which the same EC suspensions were greatly enriched (85% to 90%) for HLA-DR+T6+ LCs by flow cytometric sorting, the allostimulatory capacity of purified LCs from steroid-treated skin was not significantly different from control. Residual HLA-DR+T6+ LCs, which preserve their antigenic markers and alloantigen-presenting function, may be relatively unaffected because they have only recently immigrated into the epidermis, or they may represent a subgroup of steroid-resistant LCs. Alternatively, given the dose response relationship between topical steroid potency and decrease in HLA-DR+T6+ LC numbers, the apparent steroid resistance of residual HLA-DR+T6+ LCs may reflect heterogenity in the density of expression of LC steroid receptors.
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PMID:Flow cytometrically-sorted residual HLA-DR+T6+ Langerhans cells in topical steroid-treated human skin express normal amounts of HLA-DR and CD1a/T6 antigens and exhibit normal alloantigen-presenting capacity. 278 52

The immunophenotypes of the HLA-DR-positive leucocyte populations in normal human skin were studied using an extensive panel of monoclonal antibodies, which included antibodies from the Third International Leucocyte Differentiation Antigen Workshop (3rd LDAW). Langerhans' cells (LC) in the epidermis stained with antibodies from CD15c, Groups 10, 12a, 12b and 15, of the myeloid panel and from CD39 of the B-cell panel. However, LC did not react with CD14 antibodies or 63D3, which are frequently used to stain tissue macrophages. In addition to epidermal LC (26 cells/linear mm) a significant population of CD1a-positive cells was identified in the papillary dermis (7 cells/linear mm of overlying epidermis). The dermal HLA-DR-positive leucocytes consisted of three cell populations. The most numerous cell type stained with antibodies to monocytes/macrophages. There were fewer, though substantial, numbers of T lymphocytes (mainly CD7-negative) and the least numerous was the population of CD1a-positive cells. The CD1a-positive cells and the population of dermal cells that stain with monocyte/macrophage markers are both potential antigen-presenting cells for the skin-associated immune system.
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PMID:HLA-DR-positive leucocyte subpopulations in human skin include dendritic cells, macrophages, and CD7-negative T cells. 306 20

The simultaneous demonstration of three surface antigens of Langerhans cells (LC) within LC-enriched fresh epidermal cell suspensions from normal human skin was achieved, by means of a triple immunogold (IG) staining, using commercially available monoclonal antibodies (moAb) and immunoreagents, in a simple pre-embedding immunoelectronmicroscopy (IEM) procedure. As a result, suspended LC were triple-stained as follows: gold particles of 40 nm revealed the CD1 a antigen; gold particles of 20 nm revealed the HLA-DR antigen; and gold particles of 5 nm revealed the CD4 antigen. All the observed epidermal Birbeck granule-bearing LC were triple IG stained, thus simultaneously expressing the three surface differentiation antigens, which are therefore different from but coexisting with each other. The present investigation assesses the constant simultaneous expression by Birbeck granules bearing LC of not only CD1a and HLA-DR antigens, but also CD4 antigen. The occurrence is therefore excluded of both CD1a-positive HLA-DR-negative LC subpopulation and CD4-negative LC subpopulation, presumably due to the different sensitivity of the various procedures performed. The hypothetical occurrence of CD4-positive, CD1a-, and/or HLA-DR-negative LC subpopulations is ruled out. This study reaffirms indeed the high specificity and sensitivity of the IG-IEM method for a precise detection of the cell surface antigens of LC, and states the suitability of the IG labeling even for accurate multiple IEM stainings of LC.
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PMID:Simultaneous colloidal gold immunoelectronmicroscopy labeling of CD1a, HLA-DR, and CD4 surface antigens of human epidermal Langerhans cells. 326 98

We have investigated the mechanisms by which topical corticosteroids modulate cutaneous immune reactions in man. Volunteers applied clobetasone butyrate 0.05% (Eumovate; EV), betamethasone valerate 0.1% (Betnovate; BV), clobetasol propionate 0.05% (Dermovate; DV), and control vehicles twice daily to forearm skin for 7 days. Steroid therapy significantly decreased the number of HLA-DR/T6 (CD1a) positive Langerhans cells (LCs) per mm2 in suction blister-derived epidermal sheets, expressed as a mean percentage of controls, as follows: EV 69.2%; BV 67.3%; DV 37.8%. LC antigen presenting capacity was determined in the allogeneic and autologous epidermal cell-lymphocyte reactions. The LC-dependent allostimulatory capacity of epidermal cells, expressed as a mean percentage of controls, was also significantly reduced by steroid therapy: EV 45.1%; BV 41.9%; DV 23.4%. Following therapy with clobetasol propionate 0.05%, the capacity of epidermal cells to present tetanus toxoid to, and to augment concanavalin A mediated lymphocyte stimulation of, autologous lymphocytes was reduced to 33.6% and 19.7% respectively of controls. Depression of epidermal cell allostimulatory capacity was not the result of a steroid-induced decrease in the production of epidermal cell-derived thymocyte activating factor (ETAF)/interleukin 1 by keratinocytes, since it could not be reversed by addition of exogenous interleukin 1. Indomethacin, added to block any potential prostaglandin synthesis during the culture period, did not restore the allostimulatory capacity of epidermal cells from steroid-treated sites. Addition of epidermal cells from DV-treated sites depressed the capacity of control epidermal cells to stimulate lymphocytes in the allogeneic epidermal-lymphocyte reaction. Our results demonstrate that the anti-inflammatory action of topical corticosteroids in man is associated not only with a reduction in the number of HLA-DR/T6 positive LCs, but also with a marked decrease in Langerhans cell-dependent T lymphocyte activation. The effects of the different steroids on both of these parameters correlated with their potency as determined in the standard occlusive vasoconstrictor assay. Topical corticosteroids are widely used for the treatment of inflammatory skin disorders, and inhibit not only the elicitation phase, but also the induction phase, of allergic contact dermatitis reactions.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Effects of topical corticosteroid therapy on Langerhans cell antigen presenting function in human skin. 328 68

The human gut epithelium is a unique immunological compartment, containing substantial amounts of intra-epithelial lymphocytes (IEL) with unknown functions. In this study we show that distinct and unusual subpopulations of IEL are present at different levels of human intestine. IEL phenotypes in normal jejunum, ileum and colon were compared using immunoflow cytometry and immunohistochemistry. The expression of mRNA for recombination-activating gene-1 (RAG-1) in IEL from all three levels was compared using reverse-transcription polymerase chain reaction, and the morphology of IEL in situ was determined using immunoelectron microscopy. Surface marker profiles of isolated intestinal epithelial cells at all three levels were also investigated. On average the proportion of TCR gamma delta IEL was comparable in jejunum than ileum and colon and varied in phenotype with gut level. CD4-CD8-TCR alpha beta IEL dominated in colon but were absent in jejunum. CD8+ TCR alpha beta IEL were present at all levels but only in jejunum did they constitute the majority of all IEL. CD4+ TCR alpha beta IEL were present in similar frequencies at all levels of the gut. In general, the majority of IEL had an activated phenotype (CD45RO+, alpha E beta 7+). Furthermore, IEL exhibited phenotypes which are rare in peripheral blood. The thymocyte markers CD1a and CD1c as well as the NK cell marker CD56 were expressed on a fraction of TCR alpha beta and TCR gamma delta IEL. A small population of 'null' cells (CD45+ TCR/CD#-CD20-CD14-CD15- cells) was also present at equal proportions along the gut. Jejunal but not colonic IEL expressed RAG-1 mRNA suggesting that extrathymic T cell maturation occurs in the epithelium of small intestine. RAG-1 was expressed in CD2+TCR/CD3- and CD3+/TCR-IEL. Ultrastructurally, IEL often formed small clusters and intimate contacts with epithelial cells, suggesting cell cooperation within the epithelium. Some IEL had pseudopodium-like extensions penetrating the epithelial basement membrane suggesting transmigration. Epithelial cells in small intestine but not colon expressed heat shock protein 60 and HLA-DR. CD1a, CD1b and CD1c were not expressed on intestinal epithelial cells at any level. The distinct surface marker profiles of IEL and epithelial cells along small and large intestine suggest functional regional specialization and are compatible with the hypothesis that TCR alpha beta IEL participate in immune reactions to lumenal antigens while TCR gamma delta IEL perform surveillance of the epithelium.
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PMID:Intra-epithelial lymphocytes. Evidence for regional specialization and extrathymic T cell maturation in the human gut epithelium. 749 55

The expression of immune associated surface antigens of keratinocytes was studied in human papillomavirus (HPV) derived lesions in order to determine whether HPV types have a regulatory role in the pathogenesis of papillomas. A series of cutaneous and mucosal lesions were immunolabeled with monoclonal antibodies to the major histocompatibility complex class 1 (beta 2-microglobulin) and 2 (HLA-DR antigens), intercellular adhesion molecule (ICAM-1) and glycoprotein CD36 (OKM5) as well as CD1a (Langerhans cells), CD4, CD8 (T cells) and CD11a (LFA1 antigen). Testing for the presence of HPV was carried out by in situ hybridization with biotinylated probes for viral DNA detection and typing. We observed a drastic reduction or a loss of beta 2-microglobulin by keratinocytes from cutaneous lesions in correlation with the disappearance of Langerhans cells. Only mild alterations were observed in mucosal lesions. HLA-DR expressed by keratinocytes was only detected in condylomas and laryngeal papillomas and was usually associated with a dense inflammatory reaction. This HLA-DR expression may be correlated with an up-regulation of ICAM-1 and the presence of LFA1 positive leukocytes, mainly of CD8 phenotype, in the epithelium. CD36 was detected on differentiated keratinocytes of all lesions; its expression seems related to the proliferation state of the lesions and probably does not represent an immune marker. The different reactivity patterns observed in cutaneous and mucosal lesions may reflect: 1. different roles for mucosal and cutaneous HPV types in the induction of immunoregulatory surface antigens of keratinocytes, or 2. the changing nature of the cytokines released by mononuclear cells and infected keratinocytes in these lesions.
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PMID:Expression of immune associated surface antigens of keratinocytes in human papillomavirus-derived lesions. 750 44


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