Important note: Information in this article was accurate in 1992. The state of the art may have changed since the publication date.
THE SKIN AS AN IMMUNOCOMPETENT ORGAN (MEETING ABSTRACT)
J Cancer Res Clin Oncol; 117(Suppl II):S61 1991. Unique Identifier : AIDSLINE ICDB/92685908 Stingl G; Div. of Cutaneous Immunobiology, Dept. of Dermatology 1, Univ. of; Vienna Medical Sch., Alser Strasse 4, A-1090 Vienna, Austria
Abstract:
When, in the not-so-distant past, the skin was discussed in the context of immunological reactions, it was solely viewed as a target for immunological effector systems. Recent advances have radically changed the concept of an exclusively passive role of the skin in the immune response. In fact, there now exists ample evidence that this organ functions not only as a physicochemical, but also as an immunological barrier, by initiating immune responses against both exogenous pathogens and neoantigens generated in the skin itself. Dendritic, MHC class 1- and class II-bearing cells (ie, epidermal Langerhans cells, dermal dendrocytes) are the principal sensitizing cells in these reactions. After antigen uptake, these cells presumably leave the skin and migrate, via the dermal lymphatics, to the regional lymph node where they present the processed antigen to the naive T cell, resulting in antigen-specific T-cell stimulation. T-cell blasts, thus generated, find their way back to the skin and preferentially accumulate at the site harboring the antigen. This selective homing mechanism is mediated by the functional interaction between skin-specific homing receptors on the surface of primed T cells and corresponding ligands on the surface of either dermal microvascular endothelial cells and/or activated keratinocytes. Upon receipt of a renewed antigenic stimulus, sensitized T cells can undergo clonal expansion, resulting in the generation of effector cells/molecules sufficient in magnitude to ensure the elimination of the pathogen. According to this concept it should be expected that a numerical and/or a functional impairment of dendritic antigen-presenting cells of the skin (eg, by ultraviolet radiation or by the human immunodeficiency virus) will have deleterious consequences for the host's defense mechanisms against antigens either exogenously introduced (eg, microorganisms) or newly generated (tumor antigens) in the skin. The increased frequency of cutaneous neoplasms in chronically sun-exposed individuals and in HIV-1-infected persons support the validity of this theory.
Keywords: Dendritic Cells/IMMUNOLOGY Human Langerhans Cells/IMMUNOLOGY Lymphocyte Transformation Major Histocompatibility Complex/IMMUNOLOGY Receptors, Lymphocyte Homing/IMMUNOLOGY Skin/CYTOLOGY/*IMMUNOLOGY T-Lymphocytes/IMMUNOLOGY ABSTRACT 920930
M9290912
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Important note: Information in this article was accurate in 1992. The state of the art may have changed since the publication date.
