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 structural similarities of CD1a molecules to major histocompatibility complex (MHC) class I antigens, as well as their expression on epidermal antigen-presenting cells suggest that CD1a molecules might be involved in the cutaneous immune response. In the present study, we investigated the effect of different anti-CD1a monoclonal antibodies (BL6, DMC1, and Na1/34) on T cell proliferation induced by allogeneic epidermal cells in vitro. A significant inhibition of the mixed skin cell-lymphocyte reaction was obtained with BL6 and DMC1 monoclonal antibodies (MoAb), which recognize the same epitope on CD1a molecule. The observed inhibition could not be related to a steric hindrance of MHC class II molecules, because Na1/34 MoAb, which reacts with another epitope on CD1a molecule, had no significant effect. BL6 and DMC1 MoAb interfered with an early event of T-cell activation, as shown by a time-course study. In the presence of these MoAb, the addition of exogenous interleukin 2 did not restore T-cell proliferation. Furthermore, the inhibitory effect of anti-CD1a MoAb was not mediated by a suppressor factor released by Langerhans cells (LC). These present data suggest that CD1a molecule may have an important function in self peptide presentation by human Langerhans cells.
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PMID:A potential role for CD1a molecules on human epidermal Langerhans cells in allogeneic T-cell activation. 171 29

We have studied the effects of phorbol-dibutyrate (PBu2), a protein kinase C (PKC) activator, on the proliferation of peripheral human T cells and thymocyte subpopulations selected by treatment with monoclonal antibodies and complement: pre-thymocytes (CD1a-CD3-CD4-CD8-), cortical thymocytes (CD3-, class I- antigens) and medullary thymocytes (enriched as CD1a- cells). PBu2 induces a dose-dependent proliferative response in human peripheral blood T cells at concentrations greater than 6 ng/ml, this proliferation being mediated by the autocrine interleukin 2 (IL2)/IL2 receptor (IL2R) pathway. Pre-thymocytes respond to PBu2 in a way similar to T cells, being able to secrete IL2 in significant amounts and express the p55 chain of IL2R. On the other hand, cortical thymocytes are not induced to proliferate after PKC activation and neither expression of the p55 chain of IL2R nor IL2 secretion is observed. Human medullary thymocytes, phenotypically identical to peripheral blood T cells, show no proliferation in response to PBu2 at any concentration tested unless IL2 is supplied to the cultures. The activation of PKC induces the expression of IL2R in these cells, but not IL2 secretion. The implications of PKC activation in thymic maturation, the role of IL2 and the relevance of the differences between medullary thymocytes and peripheral blood T cells are discussed.
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PMID:Proliferative responses induced by the activation of protein kinase C during the development of human T lymphocytes. 199 83

In the defense against Mycobacterium leprae, macrophages play an essential part in the mechanism of bacterial lysis but require the presence of cytokines such as interleukin 2 and gamma interferon from lymphocytes in order to effectively kill the organisms in any number. While there have been many studies of the lymphocytes in lesions of leprosy, less attention has been given to the immunohistochemical characterization of the macrophage populations. In this study, the cutaneous lesions of 69 patients with leprosy (42 lepromatous, 5 mid-borderline, and 22 tuberculoid) were evaluated by immunohistochemistry for the expression of S100 protein, CD1a, CD68, muramidase, HLA-DR, and Factor 13a. The macrophages from lesions of polar, subpolar, and borderline lepromatous leprosy patients expressed S100 protein intensely and constantly. In contrast, the lesions of polar and subpolar tuberculoid leprosy had very few cells that were immunoreactive for S100 protein ('S100+') in the granulomas in the dermis. The macrophages in all lesions were reactive for CD68 and muramidase. In paraffin sections, macrophages of lepromatous lesions failed to stain for HLA-DR, whereas in tuberculoid lesions, they were strongly positive for HLA-DR. Three patients with histoid leprosy (relapse lesions) had lesions that were strongly positive for Factor 13a and were negative for S100 protein ('S100-'). Given the possible chemotactic and migration inhibition effects of the calcium-binding proteins of the S100 family, these data suggest a possibly important role for S100 protein in the accumulation of macrophages in lepromatous leprosy, and also reveal infection of Factor 13a + dermal dendritic cells in histoid leprosy.
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PMID:Multibacillary leprosy: lesions with macrophages positive for S100 protein and dendritic cells positive for Factor 13a. 987 Jun 71