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)

In human papillomavirus (HPV) infections, Langerhans cells (LC) are essential in the control of viral infection. The evolution of HPV-derived lesions in the normal population and in graft patients is drastically different, since a high proportion of papillomas progress towards malignancy in transplant recipients. We analyzed the distribution of markers of LC and T lymphocytes, the level of keratinocyte activation and the prevalence of HPV in a series of epithelial lesions obtained from the normal population and from graft patients. The local immune response of warts, condyloma acuminata, Bowen, basal and squamous cell carcinomas (SCC) showed a moderate to intense inflammatory reaction of HLA-DR positive cells, the intensity of the immune reaction being correlated with the degree of malignancy. In the normal population, CD4-positive cells were mainly overexpressed in the dermal infiltrate of condyloma and malignant lesions, whereas in grafted patients such infiltrates were CD4- and CD8-positive without significant predominance of a single T cell subset. The epidermis of most lesions was characterized by a reduced number of CD1a-positive LC with an altered morphology. This was concomitant with the decrease or loss of beta 2-microglobulin by epithelial cells. HLA-DR antigen was sometimes expressed by keratinocytes in genital lesions and SCC from the normal population but has not been detected in immunosuppressed patients. Whereas in the normal population HPV infection was only detected in benign papillomas, both benign and oncogenic HPV DNA may be present in carcinomas from graft patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Papilloma viruses, warts, carcinoma and Langerhans cells. 839 34

Dendritic cells (DC) have been isolated from blood, lymphoid tissue, and other tissues, as potential members of a hemopoietic lineage of specialist APC for naive T lymphocyte activation. To define human bone marrow (BM) DC we have attempted to identify allostimulatory cells with DC-like characteristics among human BM mononuclear cells (BMMC) by FACS cell sorting and immunophenotyping, monitoring the APC function of different cell lineages in the human primary MLR. We show that fresh human BM stimulates allogeneic T lymphocytes with an activity equal to or greater than that of peripheral blood. As with DC from other tissue sources, the most potent stimulatory activity was found in the low density BMMC, and these cells, like peripheral blood, stimulated a maximal allogeneic MLR response at days 5 to 6. FACS purification of the allostimulatory population in fresh human BMMC was undertaken by using a wide range of mAb directed against lineage-associated molecules of mature and immature lymphoid, erythroid, and myeloid cells. The most potent constitutive BMMC stimulatory activity was located in the CD3-, CD11b-, CD14-, CD15-, CD16-, CD19-, CD57-, and glycophorin A- population. A mixture of antibodies to these Ag was used to isolate a "mix-negative" BMMC population, which contained the most highly potent MLR-stimulatory cells. Further cytologic and immunophenotypic analysis of this population revealed an enriched population of HLA-DP+, HLA-DQ+, HLA-DR+, and CD45+ cells, with morphologic similarities to the human tonsil and blood DC. These cells were CD4- and CD1a- and were weakly CD33+ (but CD15-), suggesting a possible early myeloid origin distinct from both the committed granulocytic and monocytic lineages. In addition, they lacked both CD10 and CD20, making a lymphoid origin unlikely. Further identification of these putative DC precursors will allow analysis of the early phases of DC hemopoiesis, whereas the characterization of the MLR-stimulatory cells in human BM will be of major importance in the understanding of BM transplant failure and graft-vs-host disease.
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PMID:Identification of potent mixed leukocyte reaction-stimulatory cells in human bone marrow. Putative differentiation stage of human blood dendritic cells. 845 72

Two different subsets of CD4+,CD8+ T lymphocytes have been identified in peripheral blood collected from normal subjects and from patients with different diseases. The subpopulations differed in the degree of CD4 and CD8 antigen expression. Hence, it was possible to distinguish by cytofluorimetric analysis cells with a low (dim) or with a high (bright) fluorescence intensity after the staining with anti-CD4 or anti-CD8 mAbs. CD4+dim,CD8+bright lymphocytes were found in patients with EBV-infectious mononucleosis and were present for less than a month. CD4+bright,CD8+dim T cells were observed in neoplastic patients as well as in healthy subjects and were continuously present in similar percentages over a long period of time (at the moment, about 3 years). Both the subpopulations expressed CD2, CD3, CD5 antigens and had an alpha beta-TCR, but did not express CD1a or CD7. Only CD4+dim,CD8+bright cells expressed HLA-DR antigen and the activation marker CD38, while only CD4+bright,CD8+dim lymphocytes expressed CD56 and CD57 molecules. The hypothesis may be put forward that these two subsets represent an effort of the immune system to cope with different requirements, i.e., of viral or neoplastic origin, while it is not clear the meaning of these cells in healthy subjects.
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PMID:Cytofluorimetric identification of two populations of double positive (CD4+,CD8+) T lymphocytes in human peripheral blood. 846 Oct 16

The immunophenotype of 304 adult lymphoblastic leukemias (> 18 years) diagnosed on the basis of the FAB criteria was determined at the time of diagnosis using a panel of monoclonal antibodies. The series comprised cases diagnosed and immunophenotyped in 43 Italian centers (GIMEMA Cooperative Group) between April 1988 and June 1991. The immunophenotypic characterization consisted of two consecutive steps. The initial screening was based on the reactivity for TdT, HLA-Dr, CD7, CD10, CD13, CD19, CD24, CD33 and CD41. According to the results obtained, the second level of investigation assessed the positivity for intra cytoplasmic (Cy) Ig, CD1a, CD2, CD3, CD4, CD5, CD8 and CD20. Based on the hierarchical expression of the different B- and T-cell related antigens, each case was assigned to a given differentiation stage. B-lineage ALL were classified in five subgroups (B0-B4) and T-lineage ALL in four subgroups (T0-T3). Cases in which the blasts were lymphoid according to the FAB criteria, but expressed myeloid antigens in association with B- and T-lymphoid markers were defined as hybrid leukemias. As expected, CD10+ cases (B2-B3) were the most frequent within the B-lineage ALL (83.2% of cases). CyIg+ (B3) accounted for about 20% of CD10+ ALL. Twenty eight cases (13.4%) were at a pre-cALL stage (B0-B1) and of these, 8 (3.8% of the total series) were positive only for TdT and HLA-Dr (B0). Intermediate and mature thymic phenotypes (T2-T3) were predominant within the T-ALL (67.2%) groups. Five cases, were positive only for TdT and CD7 (CD5+), and classified as T0. 9.2% of cases fulfilled the definition of hybrid leukemia, largely in view of the co-expression of B-lymphoid and myeloid markers.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Immunophenotype of acute lymphoblastic leukemia cells: the experience of the Italian Cooperative Group (Gimema). 847 81

Pulmonary histiocytosis X (HX) is a disorder characterized by the presence of granulomas in which Langerhans cells (LC) and lymphocytes are abundant. Although the pathogenesis of pulmonary HX remains unknown, an uncontrolled immune response initiated by LC, which are potent antigen-presenting cells in vitro, may play an important role. To further characterize LC and lymphocytes present in granulomas from these patients, we used immunohistochemical techniques and monoclonal antibodies to evaluate the surface phenotype and electron microscopy (EM) to seek evidence for close interactions between both cell types in these lesions. In all samples, HX granulomas contained large numbers of strongly positive CD1a cells in which typical Birbeck granules were identified by EM. The number of Birbeck granules in LC from HX granulomas was strikingly increased compared with that in LC in the bronchioles of normal subjects. Furthermore, unlike normal LC, essentially all LC in HX granulomas expressed CD4 antigens and were strongly positive for CD1c. Lymphocytes infiltrating HX granulomas were almost entirely CD3+ T cells and were mainly CD4 positive (CD4/CD8 ratio 3.7 +/- 1.3). These T lymphocytes expressed almost exclusively alpha/beta T cell receptors, and gamma/delta T cells were rarely observed (< 5% of CD3+ cells). In areas of lymphocytic infiltration, close differentiated contacts between LC and lymphocytes were observed by EM in all samples. These results demonstrate that interactions between activated LC and CD4+ T lymphocytes are prominent in early HX granulomas and support the idea that an immune response in which LC serve as accessory cells is involved in the pathogenesis of this disorder.
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PMID:Surface phenotype of Langerhans cells and lymphocytes in granulomatous lesions from patients with pulmonary histiocytosis X. 850 66

An in vitro culture system was developed that facilitates detailed studies of the interaction of Human Immunodeficiency Virus (HIV) with dendritic cells (DC). Cultured immature DC were generated from adherent peripheral blood mononuclear cells in the presence of GM-CSF and IL-4. These cells were non-adherent, non-phagocytic and had a veiled surface appearance. They expressed high levels of MHC class I and II proteins, CD1a, B7/BB1 and low levels of CD4, and were known to possess a potent soluble antigen presenting capacity. Upon infection with the HIV-1 strains Lai (lymphocytotropic) and BaL (monocytotropic), the viral RNA was reverse transcribed to complete DNA provirus. However the infection was non-productive as judged from measuring the activity of the virus encoded reverse transcriptase in the culture supernatant. Thus HIV infection was restricted at a step post entry.
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PMID:Infection of cultured immature dendritic cells with human immunodeficiency virus type 1. 852 22

The distribution of CD1a-positive Langerhans cells, CD4-positive T-helper cells, and CD8-positive T-suppressor cells in 36 patients with transitional cell carcinoma of the urinary bladder was studied immunohistochemically on frozen sections. Multiple tissue specimens from the tumour, the adjacent mucosa, and random bladder wall biopsies were examined. Langerhans cells were mainly interspersed among the tumour cells, whereas T-helper cells were present in aggregates in the stroma. T-suppressor cells were present both in aggregates in the stroma and among the tumour cells. There was a marginal relationship between the density of Langerhans cells and the density of T-helper/inducer cells and a good relationship with CD8-positive cells. There was no statistically significant difference in the population density of Langerhans cells associated with the various clinicopathological variables, including growth pattern, histological grade and stage, or patient's age and sex. On the contrary, a statistically significant difference was found in the CD1a/CD4 ratio among specimens of different grades. These results show that CD1a cell populations correlate with T-cell populations in bladder cancer, suggesting that Langerhans cells take part in the immune response carried out by T lymphocytes, their task being apparently antigen presentation.
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PMID:Distribution of CD1a-positive Langerhans cells and lymphocyte subsets in transitional cell carcinoma of the urinary bladder. An immunohistological study on frozen sections. 856 95

CD86 (B70/B7-2) has recently been identified as an alternative CD28/CTLA-4 ligand on activated B cells. CD86 has also been demonstrated as possibly serving as a primary costimulatory molecule in the initial immune response. Since the human Langerhans cell is one of the most potent antigen-presenting cells, we examined whether CD86 expression and function are found on organ-cultured skin, freshly isolated Langerhans cells, and cultured Langerhans cells in normal human epidermis. Immunohistochemical study in situ revealed that CD86 was expressed on dendritic cells with CD1a antigen in organ-cultured but not fresh skin. Fluorescence-activated cell sorter analysis revealed that no staining for either CD80 or CD86 was observed in freshly isolated Langerhans cells but that both CD80 and CD86 were expressed on cultured Langerhans cells. The actual expression of CD86 on cultured Langerhans cells was further confirmed by the detection of 70-kDa glycoprotein on Western blot analysis. Analysis of polymerase chain reaction demonstrated that both CD80 and CD86 were specifically amplified from purified cultured and freshly isolated Langerhans cells but not from Langerhans cell-depleted epidermal cells, indicating that both CD80 and CD86 genes were expressed by Langerhans cells. The functional importance of CD86 on Langerhans cells was confirmed by the allogeneic CD4 T cell proliferative responses with enriched Langerhans cells. A monoclonal antibody against CD86 caused 81% inhibition in contrast with 29% inhibition produced by anti-CD80 monoclonal antibody. This inhibitory effect was enhanced to 85.3% inhibition when a combination of anti-CD86 and anti-CD80 was administered. These results indicate that CD86 is predominantly expressed on the surface of cultured Langerhans cells and may transduce a primordial costimulatory signal in the interaction of Langerhans cells and T cells.
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PMID:Functional CD86 (B7-2/B70) on cultured human Langerhans cells. 859 66

Human Langerhans cells (LC) are CD1a+ dendritic cells (DC) that function as potent antigen-presenting cells for primary and secondary immune responses. Limitations in DC/LC numbers, imposed by difficult and tedious isolation procedures, have so far precluded their use as immunogens in the generation and/or augmentation of host responses against various pathogens. Therefore, we have developed a procedure for the generation of human DC/LC from CD34+ hematopoietic progenitor cells (HPC) isolated (mean: 0.7 x 10(6)/ buffy coat and 2.6 x 10(6)/leukapheresis product) and purified ( > 95%) from the peripheral blood of healthy adults. In vitro stimulation of these cells with granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor (TNF)-alpha led to their vigorous proliferation and differentiation resulting in the emergence of CD45+/CD68+/CD3-/CD19-/CD56- leukocytes some of which (mean: 12%) express CD1a and exhibit anti-CD4 and anti-major histocompatibility complex (MHC) class II reactivity. These CD1a- leukocytes include (1) LC as evidenced by the presence of Birbeck granules (BG), (2) CD14+ monocytes, and (3) Birbeck granule-negative cells with a dendritic morphology. Addition of interleukin (IL)-4 to the cytokine cocktail interfered with the development of monocytes and led to a reduction in the overall yield but, on the other hand, resulted in an increased percentage of CD1a+ cells (mean: 24%) among all cells generated. In vitro generated CD1a+, but not CD1a- HPC-derived cells are potent stimulators of the primary mixed leukocyte reaction and, as such, promising candidates for vaccination purposes.
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PMID:Generation of human dendritic cells/Langerhans cells from circulating CD34+ hematopoietic progenitor cells. 860 17

Canine cutaneous histiocytoma (CCH) is a common, benign neoplasm of the dog. Histiocytomas most commonly occur as solitary lesions that undergo spontaneous regression. The age-specific incidence rate for histiocytomas drops precipitously after 3 years, although histiocytomas occur in dogs of all ages. Langerhans cells (LCs) in humans and dogs express abundant major histocompatibility complex class II molecules and a variety of leukocyte antigens characteristic of dendritic cell differentiation including CD1a, CD1b, CD1c, and CD11c. The immunophenotype of CCH resembled that of cutaneous LCs by virtue of the expression of CD1 molecules (CD1a, -b, and -c), CD11c, and major histocompatibility complex class II. Furthermore, histiocytoma cells had a tropism for epidermis, which was also consistent with an epidermal LC lineage. The expression of adhesion molecules such as CD11b (variable), CD44, CD54 (ICAM-1), and CD49d (VLA-4) in CCH indicated that the infiltrating cells had some of the characteristics of activated LCs, as these molecules are not expressed by normal, resting canine epidermal LCs. CCH did not express Thy-1 or CD4. Thy-1 expression is a characteristic of human and canine dermal dendrocytes, which are perivascular dendritic antigen-presenting cells closely related to epidermal LCs. CD4 expression is prevalent in human LC histiocytosis, and in this respect CCH differed from human LC histiocytosis. Here we demonstrate that CCH is a localized form of self-limiting LC histiocytosis, which predominantly expresses an epidermal LC phenotype. CCH occurs as solitary or, less commonly, as multiple cutaneous nodules or plaques, which rarely may extend beyond the skin to local lymph nodes. Regression of CCH occurs spontaneously in the vast majority of cases in primary and secondary sites, and is mediated by CD8+ alpha beta T cells. The high frequency of CCH within the general canine population offers the potential that the dog may provide an interesting model system to further the understanding of LC proliferative disorders, particularly the self-limiting, cutaneous form of human LC histiocytosis.
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PMID:Canine cutaneous histiocytoma is an epidermotropic Langerhans cell histiocytosis that expresses CD1 and specific beta 2-integrin molecules. 862 37


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