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Query: UNIPROT:P06126 (CD1a)
 2,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Langerhans cells (LCs) play a sentinel role by initiating both adaptive and innate immune responses to antigens pertinent to the skin. With the discovery of various LCs markers including antibodies to major histocompatibility complex class II (MHC-II) molecules and CD1a, intracellular presence of racket-shaped "Birbeck granules," and very recently Langerin/CD207, LCs can be readily distinguished from other subsets of dendritic cells. Femtosecond two-photon laser scanning microscopy (TPLSM) in recent years has emerged as an alternative to the single photon-excitation based confocal laser scanning microscope (CLSM), particularly for minimally-invasive deep-tissue 3D and 4D vital as well as nonvital biomedical imaging. We have recently combined high resolution two-photon immunofluorescence (using anti MHC-II and Langerin/CD207 antibodies) imaging with microspectroscopy and advanced image-processing/volume-rendering modalities. In this work, we demonstrate the use of this novel state-of-the-art combinational approach to characterize the steady state 3D organization and spectral features of the mouse epidermis, particularly to identify the spatial distribution of LCs. Our findings provide unequivocal direct evidence that, in the mouse epidermis, the MHC-II and mLangerin/CD207 antigens do indeed manifest a high degree of colocalization around the nucleus of the LCs, while in the distal dendritic processes, mLangerin/CD207 antigens are rather sparsely distributed as punctuate structures. This unique possibility to simultaneously visualize high resolution 3D-resolved spatial distributions of two different immuno-reactive antigens, namely MHC-II and mLangerin/CD207, along with the nuclei of LCs and the adjacent epidermal cells can find interesting applications. These could involve aspects associated with pragmatic analysis of the kinetics of LCs migration as a function of immuno-dermatological responses during (1) human Immunodeficiency virus disease progression, (2) vaccination and targeted gene therapy, (3) skin transplantation/plastic surgery, (4) ultraviolet and other radiation exposure, (5) tissue-engineering of 3D skin constructs, as well as in (6) cosmetic industry, to unravel the influence of cosmeceuticals.
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PMID:Femtosecond two-photon high-resolution 3D imaging, spatial-volume rendering and microspectral characterization of immunolocalized MHC-II and mLangerin/CD207 antigens in the mouse epidermis. 1694 65

Histiocytic proliferative diseases include reactive and neoplastic proliferations of dendritic cells (DC) or macrophages. Various forms of DC proliferations have been documented in humans and dogs; their etiology is largely unknown. With the exception of a few case reports, histiocytic proliferations have not been characterized in cats. This study summarizes clinical, morphologic, and immunophenotypic features of a feline progressive histiocytosis (FPH) in 30 cats. There was no breed or age predilection. Females were more often affected than males. Solitary or multiple nonpruritic firm papules, nodules, and plaques had a predilection for feet, legs, and face. Lesions consisted of poorly circumscribed epitheliotropic (13/30) and nonepitheliotropic (17/30) histiocytic infiltrates of the superficial and deep dermis, with variable extension into the subcutis. The histiocytic population was relatively monomorphous early in the clinical course. With disease progression, cellular pleomorphism was more frequently encountered. Histiocytes expressed CD1a, CD1c, CD18, and major histocompatibility complex class II molecules. This immunophenotype suggests a DC origin of these lesions. Coexpression of E-cadherin, a feature of cutaneous Langerhans cells, was only observed in 3 cats. FPH followed a progressive clinical course; the lesions, however, were limited to the skin for an extended period of time. Terminal involvement of internal organs was documented in 7 cases. Treatment with chemotherapeutics or immunosuppressive and immunomodulatory drugs was not successful. The etiology of FPH remains unknown. FPH is best considered an initially indolent cutaneous neoplasm, which is mostly slowly progressive and may spread beyond the skin in the terminal stage.
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PMID:Feline progressive histiocytosis. 1696 41

A number of antigen-presenting cells (APCs) expressing major histocompatibility complex class II (MHC-II) have been identified in healthy human skin including the Langerhans cells of the epidermis and the three recently defined dermal APC subsets. It is well documented that in other tissues HLA-DR expression is not exclusive to APCs. Following a comprehensive analysis of the cells in human skin using flow cytometry and fluorescence immunohistochemistry, we have identified additional cell subsets that express HLA-DR. Using markers exclusive for blood and lymphatic endothelium, we demonstrated that both of these cell populations have the capacity to express HLA-DR. In addition, a small subset of dermal T lymphocytes was found to express low-level HLA-DR suggesting an activated phenotype. Dermal T lymphocytes were often in intimate contact with either CD1a(+) CD207(-) dermal APCs or CD1a(+) CD207(+) dermal Langerhans cells, possibly explaining the activated phenotype of a subset of dermal T lymphocytes.
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PMID:Comprehensive analysis of MHC-II expression in healthy human skin. 1734 64

Inflammatory myofibroblastic tumors with involvement of cranial and peripheral nerves are exceedingly rare. The authors present the case of a 67-year-old man with an inflammatory myofibroblastic tumor of the left ulnar nerve, which was identified intraoperatively and mimicked a malignant neoplastic lesion. Histopathological examination revealed loosely structured fibrous tissue and collagen deposits intermingled with patchy infiltrates of lymphocytes, plasma cells, and histiocytes penetrating the endo- and epineurium of the affected nerve fascicles. There was strong expression of vimentin and actin in spindle cells throughout the lesion. The histiocytes were CD68- and major histocompatibility complex class II-positive, but lacked CD1a expression. A review of the literature revealed nine histopathologically confirmed cases of inflammatory myofibroblastic tumors involving peripheral or cranial nerves in which slight differences in histopathological features and surgical management were found, which are discussed here.
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PMID:Inflammatory myofibroblastic tumor of the ulnar nerve. Case report and review of the literature. 1756 82

Various models of reconstructed epidermis already provide useful tools for safety and efficacy assessment of cosmetic products. However, the majority of these in vitro models are composed of keratinocytes only. Recently, the introduction of melanocytes into epidermal reconstructs has considerably enlarged their field of application. Depending on the melanocyte donor, the different phototypes (I-VI) as well as the racial specific pigmentation, caucasian, Asiatic or black epidermis can be reproduced in vitro. The reconstructed pigmented epidermis allows the evaluation of modulators of melanogenesis such as the depigmenting agent kojic acid. In contrast to conventional melanocyte cultures, the pigmented reconstructed epidermis is air-exposed and covered, as in vivo, with a stratum corneum. This allowed us to evaluate the effect of UV-irradiations on the epidermis and its protection by topically applied sunscreens. The introduction of resident epidermal Langerhans cells into the reconstructed epidermis remained an important challenge. We succeeded by seeding blood derived CD34+ hematopoietic progenitors onto a reconstructing epidermis composed of keratinocytes and melanocytes. The resulting pigmented epidermis shows melanocytes in the basal layer and resident epidermal Langerhans cells suprabasally. As in normal skin, the melanocytes transfer melanin to the neighboring keratinocytes, and the Langerhans cells express major histocompatibility complex class II molecules, CD1a antigen and Birbeck granules. This reconstructed epidermis, comprising for the first time the three major epidermal cell types, has the potential to serve in the near future as a predictive model for immuno-pharmaco-toxicological in vitro studies.
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PMID:Potential cosmetic applications of reconstructed epidermis. 1850 30

A 16-year-old neutered male Burmese cat was presented with a locally invasive nasal mass. The cytological and histological findings on incisional biopsy of this mass were suggestive of histiocytic sarcoma. Tumour cells expressed CD18, major histocompatibility complex class II, lysozyme and alpha-naphthyl acetate esterase; and lacked expression of CD3, CD79a, CD1a, CD1b, calprotectin, CD11c and E-cadherin. These findings are consistent with a myeloid-macrophage lineage. Metastasis to the bone marrow was present on necropsy examination. Histiocytic sarcoma should be considered in cats presented with primary round cell neoplasia of the nasal cavity.
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PMID:Primary nasal histiocytic sarcoma of macrophage-myeloid cell type in a cat. 2252 Feb 53


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