Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019621 (Langerhans cell histiocytosis)
 3,250 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

The characteristic cell type involved in Langerhans cell histiocytosis, 'LCH cells', express most of the enzyme histochemical and immunocytochemical markers of normal epidermal Langerhans cells. It is not known, however, whether these LCH cells express the functional characteristics of normal epidermal Langerhans cells. We studied the alloantigen-presenting activity of LCH cells derived from lesional sites of three patients with the disease. Lesional cells expressing the CD1a molecule were enriched using either fluorescein-activated cell sorting or negative selection with indirect immunomagnetic beads, and functional activity was assessed using the 6-day primary allogeneic mixed-cell reaction. Compared to epidermal Langerhans cells from healthy controls, LCH cells showed minimal alloantigen-presenting activity on a per-cell basis. The diminished activity was not reversed by exogenous prostaglandin synthetase inhibitor or recombinant human IL-1 beta. This study confirms our previous report of a child, with fatal multisystem Langerhans cell histiocytosis suggesting that this disease represents a condition in which functionally defective cells of Langerhans cell phenotype accumulate and/or proliferate in various tissues. We postulate that the functional defect is a primary defect of these LCH cells that have acquired an as-yet-undetermined biological insult(s).
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PMID:Functional defect in cells involved in Langerhans cell histiocytosis. 853 24

The human CD1a molecule is a transmembrane protein which shares structural similarities with HLA class I molecules. It has restricted tissue distribution in normal individuals, and is a useful diagnostic marker for certain disease states such as Langerhans cell histiocytosis. In order to investigate the function of this molecule, a cDNA fragment encoding the CD1a molecule was cloned into several EUKARYOTIC expression vectors which were then used to establish human epithelial cell lines stably expressing the membrane-bound CD1a molecule. Human keratinocytes (HaCaT) and epithelial cells (HeLa) stably expressing CD1a were established by retroviral-mediated gene transfer and DNA transfection, respectively. Expression and localization of the CD1A molecule were then confirmed by Northern blot analysis and immunofluorescence methods. CD1a expression appears to have profound effects on cellular growth and morphology. Both stably CD1a-expressing HeLa and HaCaT cells showed increased doubling times, and up to 20% of CD1a-expressing cells showed altered cell morphology. Clonogenicity experiments demonstrated a reduction in colony size and plating efficiency was augmented in CD1a-positive cells when compared with vector-transfected/infected controls. Our findings suggest that CD1A expression may act as a negative growth regulator in these cells in vitro. Furthermore, lower temperatures greatly enhanced the expression of CD1a at both the protein and mRNA levels in a time-dependent fashion. Since the physiological skin temperatures lie well below the core temperature, this observation may have important implications in the study of Langerhans cells in vitro.
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PMID:Stable expression of CD1a molecule in human epithelial cell lines shows temperature-dependent expression and affects cell morphology and growth. 920 82