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)

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

The molecules encoded by the major histocompatibility complex play a pivotal role in regulatory interactions between cells of the immune system, which can result in the activation and function of T cells. The function of the CD1 molecules, which are homologous to the major histocompatibility complex-encoded molecules but are encoded on human chromosome 1, is not known. HLA class I molecules and CD1a heavy chains share the ability to associate with several different cell-surface molecules. We show here, by several technical approaches, that HLA class I molecules are associated with CD1a heavy chains on the surface of normal thymus cells. The functional significance of this association during T-cell differentiation is discussed.
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PMID:HLA class I molecules are associated with CD1a heavy chains on normal human thymus cells. 245 69

The CD1 locus encodes a family of major histocompatibility complex (MHC) antigen-like glycoproteins which associate with beta 2-microglobulin and are expressed on immature thymocytes and Langerhans cells. Three CD1 molecules have been identified by monoclonal antibodies and molecular cloning: CD1a, -b, and -c. We have isolated a cDNA coding for a fourth CD1 molecule from a human thymocyte library and termed this molecule CD1d. Reported here are the complete nucleotide sequence and genomic organization of CD1d. They predict that this molecule is related to the previously identified CD1a, -b, and -c molecules and to MHC class I molecules, with three external domains, a transmembrane domain, and a short cytoplasmic tail. The sequence of CD1d is the most divergent among the CD1 molecules in the membrane-distal alpha 1 and alpha 2 domains and in the 5' untranslated region. In contrast, all four CD1 molecules are highly homologous in the membrane-proximal alpha 3 domain, which is likely involved in beta 2-microglobulin binding. A comparison of CD1 and MHC class I sequences suggests that these molecules each evolved to interact with a distinct set of cell surface proteins.
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PMID:Isolation and characterization of a cDNA and gene coding for a fourth CD1 molecule. 246 22

Beta 2-microglobulin (beta 2m) forms the invariant light chain of the MHC-encoded HLA-ABC and the non-MHC-encoded CD1 molecules. While HLA-ABC (MHC Class I) molecules are virtually ubiquitous in tissue distribution, CD1 determinants by contrast are more restricted. We have assessed, by indirect immunoenzymeassay, the relative membrane densities of these molecules on malignant thymic and post-thymic T cells. It was found that the T cells of mature post-thymic proliferations expressed significantly more beta 2m-associated protein, predominantly HLA-ABC in nature, than thymic-ALL blasts. This parallels the situation found in normal peripheral T cells and thymocytes. In contrast to post-thymic T cells, thymic-ALL blasts showed considerable case to case variation with respect to non-HLA-associated beta 2m and, of particular interest, not all of this excess beta 2m could be accounted for by CD1a. We therefore conclude that other beta 2m-containing molecules may be expressed on thymic-ALL blasts and possibly also on post-thymic leukaemic T cells. In addition, it was found that T cells from CD4+ cases of post-thymic proliferations expressed more beta 2m-associated determinants than other T cells, whether of either normal or malignant origin, and that certain post-thymic malignancies express significantly increased levels of beta 2m-associated protein relative to normal peripheral T-cells. This is in direct contrast to the situation seen in many solid malignancies.
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PMID:MHC class I and class I-like gene product expression by malignant T cells: relationships between CD1a, HLA-ABC and beta 2-microglobulin. 246 92

Herein, we report the DNA sequence of two human CD1 genes, R2 and R3, distinct from those encoding the CD1a, -b and -c antigens. Both genes appear to have an exon/intron structure analogous to the previously analyzed CD1 genes and to be functional on the basis of their sequence. Analysis of the variability patterns, potential intramolecular interactions and predicted secondary structure profile on an alignment of all known CD1 alpha chains suggest some shared structural features with major histocompatibility complex class I molecules in the alpha 1 domains but substantial differences in the alpha 2 domains. Sequence comparison shows that, while R2 is most related to CD1a, -b and -c, albeit to a somewhat lower degree than the latter are to themselves, R3 is more homologous to mouse than to human CD1, suggesting the existence of two functional classes within the CD1 gene family. We propose to retain the non-committal R2 and R3 names until the putative antigens have been identified and their tissue distribution has been established.
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PMID:Two classes of CD1 genes. 246 14

Immunocytochemical studies, using the antibodies CAM 5.2 and NA1/34 (CD1a), were performed on normal lymphoid tissue and malignant lymphomas. A population of dendritic cells in the paracortex of lymph nodes and in T cell lymphomas reacted with both antibodies. Colocalisation with antibodies was also found in gastrointestinal epithelium. Immune blotting shows that the likely basis of this reactivity is a 12 kilodalton peptide which is recognised by both antibodies. This is almost certainly the beta t peptide which has been described as the light chain of CD1a.
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PMID:Association between CAM 5.2 and anti-CD1a reactivity in lymph nodes and gastrointestinal tract epithelium. 246 25

Human epidermal Langerhans cells express two (CD1a and CD1c) of the three human thymic cell surface differentiation antigens (CD1a, CD1b, and CD1c). The first cluster of differentiation antigens (CD1) is defined by a group of monoclonal antibodies (MCA). All these MCA were obtained after immunization of mice or rats with human cortical thymocytes. OKT6 MCA (a CD1a MCA) was the first to be described as reactive with human epidermal Langerhans cells. We produced a murine MCA, called DMC1, after immunization with proliferating Langerhans cells of Eosinophilic Granuloma of the bone (Histiocytosis X). In tissues DMC1 MCA reacted with epidermal dendritic cells (Langerhans cells) in the skin and cortical thymocytes in the thymus as observed on indirect immunofluorescence. At the ultrastructural level, DMC1 MCA was specific for Birbeck granule-containing Langerhans cells and did not react with melanocyte and keratinocyte populations. The quantitative analysis of immunoelectron labeling and the cytofluorometric study showed that the intensity of labeling was inversely correlated with the concentration of trypsin used in the preparation of epidermal cell from skin samples. DMC1 MCA precipitated a protein with a relative mass of 49,000 (CD1a molecule) from lysates of iodinated epidermal Langerhans cells under reducing conditions. It recognized the original CD1a molecule (Mr 49,000) but not the membrane breakdown product of CD1a (Mr 27,000) brought about by trypsin.
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PMID:DMC1: a monoclonal antibody produced from histiocytosis X cells which reacts with the native CD1a molecule of human epidermal Langerhans cells. 246 37

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

We have studied the expression of CD1 antigens on peripheral blood mononuclear cells (PBMC) from acute hepatitis B patients in order to analyse a possible role for CD1 antigens in hepatitis B virus (HBV) infection. Using immunofluorescence and the monoclonal antibodies which recognized CD1a, CD1b and CD1c molecules, we have shown that CD1 antigens were expressed on PBMC from acute hepatitis B patients but not from other acute and chronic liver disease. Dot blot analysis on nitrocellulose sheets of the lysates of the cells confirmed these observations. Cell fractionation and double-labelling experiments clearly demonstrated the CD1 antigens were expressed only on non-T cells. Furthermore, CD1 antigens were coexpressed with hepatitis B surface antigen (HBsAg) on the surface of Ig-positive cells. These results could indicate that CD1 expression may be associated with the lymphotropic effect of HBV.
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PMID:Expression of CD1 antigens by peripheral blood mononuclear cells from hepatitis B patients. 247 37

To develop methods for the investigation of mRNA transcription in rare epidermal cells, we used in situ transcription to study CD1a mRNA in isolated CD1a positive cells. We chose to study this Langerhans cell marker because it is not known which epidermal cells actually produce the CD1a protein and because there is evidence that CD1a mRNA is alternately spliced, a situation which could lead to truncated or alternate protein products in CD1a surface protein negative cells. Disaggregated epidermal cells were resolved into CD1a surface protein positive and negative groups by fluorescence activated cell sorting and cytocentrifuged onto glass slides. A synthetic 52 base, CD1a specific anti-sense oligomer was hybridized to CD1a gene transcripts in these cells, and radiolabeled cDNA synthesized in situ on the oligomerprimed CD1a transcripts. The labeled cDNA fragments were visualized in the cells of origin by autoradiography, and grains per cell were counted. Sixty-eight percent of cells expressing CD1a protein contained CD1a mRNA, as evidenced by grain counts more than two standard deviations above the mean value for similar cells carried through the same procedure with a control oligomer, or the mean value of CD1a surface protein negative cells treated with the CD1a specific oligomer. Thus, it seems likely that the CD1a protein positive epidermal cells use CD1a mRNA to make their own CD1a protein, and that a truncated or masked CD1a protein is not made by CD1a negative neonatal foreskin epidermal cells. In our hands, in situ transcription is simpler and faster than standard methods of in situ hybridization with prelabeled cDNA or RNA probes. Furthermore, it can be applied to the detection of any message of known sequence. The combination of cell sorting and in situ transcription can be used to localize and quantify the expression of specific mRNA by individual cells, allowing the study of rare and difficult-to-obtain cells.
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PMID:In situ transcription and detection of CD1a mRNA in epidermal cells: an alternative to standard in situ hybridization techniques. 247 50


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