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 human gut epithelium is a unique immunological compartment, containing substantial amounts of intra-epithelial lymphocytes (IEL) with unknown functions. In this study we show that distinct and unusual subpopulations of IEL are present at different levels of human intestine. IEL phenotypes in normal jejunum, ileum and colon were compared using immunoflow cytometry and immunohistochemistry. The expression of mRNA for recombination-activating gene-1 (RAG-1) in IEL from all three levels was compared using reverse-transcription polymerase chain reaction, and the morphology of IEL in situ was determined using immunoelectron microscopy. Surface marker profiles of isolated intestinal epithelial cells at all three levels were also investigated. On average the proportion of TCR gamma delta IEL was comparable in jejunum than ileum and colon and varied in phenotype with gut level. CD4-CD8-TCR alpha beta IEL dominated in colon but were absent in jejunum. CD8+ TCR alpha beta IEL were present at all levels but only in jejunum did they constitute the majority of all IEL. CD4+ TCR alpha beta IEL were present in similar frequencies at all levels of the gut. In general, the majority of IEL had an activated phenotype (CD45RO+, alpha E beta 7+). Furthermore, IEL exhibited phenotypes which are rare in peripheral blood. The thymocyte markers CD1a and CD1c as well as the NK cell marker CD56 were expressed on a fraction of TCR alpha beta and TCR gamma delta IEL. A small population of 'null' cells (CD45+ TCR/CD#-CD20-CD14-CD15- cells) was also present at equal proportions along the gut. Jejunal but not colonic IEL expressed RAG-1 mRNA suggesting that extrathymic T cell maturation occurs in the epithelium of small intestine. RAG-1 was expressed in CD2+TCR/CD3- and CD3+/TCR-IEL. Ultrastructurally, IEL often formed small clusters and intimate contacts with epithelial cells, suggesting cell cooperation within the epithelium. Some IEL had pseudopodium-like extensions penetrating the epithelial basement membrane suggesting transmigration. Epithelial cells in small intestine but not colon expressed heat shock protein 60 and HLA-DR. CD1a, CD1b and CD1c were not expressed on intestinal epithelial cells at any level. The distinct surface marker profiles of IEL and epithelial cells along small and large intestine suggest functional regional specialization and are compatible with the hypothesis that TCR alpha beta IEL participate in immune reactions to lumenal antigens while TCR gamma delta IEL perform surveillance of the epithelium.
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PMID:Intra-epithelial lymphocytes. Evidence for regional specialization and extrathymic T cell maturation in the human gut epithelium. 749 55

Antibodies to the CD6 Ag have been described as having pan-T cell reactivity. We have recently demonstrated, however, that after treatment of PBL with an anti-CD6-blocked ricin-conjugated immunotoxin, clonal populations of CD3+, CD6- cells can be identified. Herein we show that through dual parameter staining of freshly isolated E-rosette+ cells, an average of 5 to 6% of either CD3+ or CD5+ cells express little or no CD6 on their surface. After negative selection by antibody-coated paramagnetic bead depletion, expanded CD6- T cells were shown to be CD1a-, CD2+, CD3+, CD5+, CD16-, CD56-, TCR-gamma/delta-, and consisted of both CD4+ and CD8+ cells. Furthermore, staining of digitonin permeabilized cells showed no cytoplasmic expression of the CD6 Ag and CD6 mRNA was not detected by Northern blot analysis. Identical staining patterns were observed for T cell clones isolated through bead depletion or immunotoxin treatment and expanded with either PHA or immobilized anti-CD3 mAb. It was also found that, relative to unfractionated T cells, the surface expression of CD5 was significantly diminished on CD6- T cells. Functionally, freshly isolated CD6- T cells showed substantially reduced alloreactivity in MLR compared with unfractionated E-rosette+ cells, yet both gave similar proliferative responses to either PHA or soluble tetanus toxin Ag. We conclude that there exists a minor subpopulation of mature T cells in peripheral blood that lack CD6. The diminished alloreactivity of these cells may help to explain the low incidence of graft-vs-host disease, despite high levels of engraftment, that has been reported in allogeneic bone marrow transplant patients receiving marrow treated with anti-CD6 (T12) mAb plus C'.
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PMID:Isolation and characterization of CD6- T cells from peripheral blood. 790 89

To date no hematopoietic progenitors of dendritic Langerhans' cells (DLC), which represent an highly efficient class of antigen presenting cells, have been identified or the cytokines they elaborate have been defined. Here we describe an acute leukemia patient whose blasts (90-96% in peripheral blood and bone marrow) had a phenotype consistent with putative progenitors of DLC. The patient was treated with ara-C and VP-16 but did not achieve remission. The blasts had lobulated nuclei, no cytoplasmic vacuolation or Auer rods and were weakly positive for acid phosphatase and non-specific esterase and negative for PAS, granzyme A, dipeptidyl aminopeptidase IV, ATPase/ADPase and lysozyme production. The blasts were positive for CD1a, CD4, CD16, CD35, HLADR, HLADQ, CD11b, CD11c, CD14, CD33, CD34, CD11a, CD71, CD19, CD25, IL-2R beta and negative for CD2, CD7, CD8, CD10, CD22, CD56, CD57, surface or cytoplasmic CD3, TCR delta and TCR beta, HTLV-1p19 and P-glycoprotein. On liquid culture with or without 5 x 10(-9) M 12-O-tetradecanoylphorbol-13-acetate (TPA) for 3 days, the blasts formed aggregates of proliferating and elongating cells on the wall of the flasks with a decline in CD34, numerous dendritic processes appeared on the cells and there was strong positivity for ATPase/ADPase, but no other changes in phenotype. No macrophages were observed, indicating derivation from separate DLCs. Cytogenetic analysis showed chromosomal abnormalities and electron microscopy showed Birbeck granules. Southern blotting of DNA showed rearrangement of one allele for both JH and TCR beta but no HTLV-1 related sequences. Culture supernatants from blasts cultured with or without TPA showed the production of large amounts of IL-8, IL-6, TNF-alpha, MIP-1 alpha, IL-10 and interferon gamma and modest amounts of IL-1 alpha, GM-CSF and stem cell factor. The presence not only of CD1a, HLADR, HLADQ and many other characteristics including Birbeck granules, but also differentiation along the lines of DLC with appearance of dendritic processes on the cells and expression of ATPase/ADPase activity, indicate that the leukemic blasts in our patient represented a leukemic counterpart of normal progenitors of DLC and the leukemia a new entity which could possibly be classified as AML-M8. Lastly, many pro-inflammatory cytokines produced by DLC could contribute to inflammation and IL-10 to immunosuppression.
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PMID:Phenotype, genotype and cytokine production in acute leukemia involving progenitors of dendritic Langerhans' cells. 791 55

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

We report a case of CD30 positive anaplastic large cell lymphoma of T-cell phenotype developing in association with long-standing tuberculous pyothorax. Phenotypic analysis showed CD1a-, CD2+, CD3+, CD4+, CD5-, CD8-, CD10-, CD19-, CD20 +/-, CD21-, CD25-, CD56-, T-cell receptor (TCR) alpha/beta antigens-, and HLA-DR+ phenotype. Neither rearrangement of TCR beta and gamma chain genes or of immunoglobulin heavy chain gene was detected in DNA extract from fresh material. The lymphoma cells were also shown to express the latent membrane protein-1 and the Epstein-Barr virus (EBV)-encoded nuclear antigen-2 by immunohistochemistry and EBV-encoded small RNAs by in situ hybridization.
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PMID:Ki-1 (CD30) positive anaplastic large cell lymphoma of T-cell phenotype developing in association with long-standing tuberculous pyothorax: report of a case with detection of Epstein-Barr virus genome in the tumor cells. 852 14

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

During allogeneic bone marrow transplantation (BMT), host epidermal Langerhans cells (LC) are depleted and replaced by LC derived from the bone marrow inoculum. LC have recently been shown to form intimate spatial associations with intraepithelial nerves (IEN), which release regulatory peptides. The present study investigated whether the IEN network within skin remains intact during BMT, and whether repopulating LC re-established contacts with IEN. Double-labeling immunohistochemical techniques were employed using antibodies to CD1a and neural cell adhesion molecule (CD56) to identify LC and IEN, respectively. LC were depleted by conditioning for BMT, and repopulating LC reached normal values after day +100. In contrast to fluctuations in the LC network, the frequency of IEN remained unchanged during the post-BMT period. Contacts between LC and IEN were present both before and after BMT, and repopulating LC established a spatial interaction with IEN similar to that seen before BMT. These data provide the first evidence for the dynamic nature of the spatial relationship of LC with IEN, and raise intriguing questions regarding the mechanisms that direct homing of LC within epithelia.
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PMID:Reconstitution of cutaneous neural-immunological networks following bone marrow transplantation. 861 Mar 53

The human dermis contains a heterogeneous network of cells with a dendritic morphology, including factor XIIIa+ dermal dendrocytes and CD34+ dendritic cells located around epidermal adnexae. Whereas dermal dendrocytes have been immunohistochemically studied, CD34+ dermal cells have not yet been well characterized. We studied by simple and double immunolabeling techniques on tissue sections of normal human skin the phenotype of these cells and found them to express vimentin and Te7 but none of the remaining markers sought (factor XIIIa, von Willebrand factor, CD1a, CD3, CD4, CD8, CD14, CD25, CD36, CD45, CD54, CD56, LFA-1, EGF-R, S-100 protein, Mac 387, and muscle-specific actin). Rare CD34+ cells of the interstitial dermis expressed human leukocyte antigen (HLA)-DR antigens, but this was not the case for periadnexal CD34+ cells. These results show that CD34+ dendritic cells of human dermis are mesenchymal cells bearing a unique immunophenotype different from that of (myo)fibroblasts, monocytes-macrophages, Langerhans cells, and factor XIIIa+ dermal dendrocytes. Whereas the involvement of CD34+ cells in some cutaneous tumors is well known, their physiologic role in normal skin remains to be established. On the basis of our results, we speculate that these cells could represent uncommitted mesenchymal cells, unique by virtue of CD34 antigen expression.
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PMID:Immunohistochemical study of CD34-positive dendritic cells of human dermis. 979 Jan 22

Dendritic cells are potent stimulators of Ag-specific T cell responses and have been implicated in the pathogenesis of HIV-1 and other viral infections. Although cytokines may be involved in both of these processes, there is little information on the expression of cytokines by human blood dendritic cells. We characterized cytokine gene and protein expression in dendritic cells that were purified from normal human PBMC by flow cytometry and stimulated in vitro for up to 24 h with HIV-1 or herpes simplex virus (HSV). The unstimulated, uncultured dendritic cells were defined by their phenotype (HLA DR+ CD3- CD19- CD16- CD56- CD14-) and distinct morphology, lack of mRNA expression for CD3, CD14 and CD19, and presence of mRNA for CD4 and CD83. The purified dendritic cells also expressed CD4 (70-90%), CD33 (36-48%), and CD11c (44-54%); lacked CD1a expression (<1%); and were potent stimulators of an allogeneic MLR. The stimulated dendritic cells expressed mRNA for IFN-alpha, IL-1alpha, IL-1beta, IL-6, IL-10, IL-12, GM-CSF, and TNF-alpha within 4 to 12 h as determined by reverse transcription-PCR, with higher levels induced by HSV compared with HIV-1 strains IIIb or BaL. In contrast, the dendritic cells produced detectable protein only for IFN-alpha and IL-6 in response to HIV-1 or HSV, and IL-1beta in response to HSV within 24 h. There were no differences in expression of CD80 and CD86 surface molecules by dendritic cells that were either mock stimulated or stimulated with HIV-1 or HSV for 24 h. Production of IFN-alpha, IL-1beta, and IL-6 by dendritic cells may be important to the immunologic function of these cells and their role in the pathogenesis of HIV-1 and HSV infections.
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PMID:Cytokine expression by human peripheral blood dendritic cells stimulated in vitro with HIV-1 and herpes simplex virus. 889 36

Papular xanthoma (PX) is a very rare skin disorder. We describe a typical case of PX in a 13-month-old Chinese boy who presented with numerous yellow-red papulonodules, 2-8 mm in diameter, mainly on the face, both upper extremities, and abdomen of 10 months duration. Histologic studies showed a diffuse monomorphous infiltrate of foamy cells in the upper dermis. The foamy cells stained positively with oil red O and CD68. The periodic acid Schiff (PAS) stain, S-100 protein, CD1a, CD56, lysozyme, alpha1-antitrypsin, and factor XIIIa were all negative in the foamy cells. The electron microscopic (EM) studies revealed the morphologic features of macrophages with electron-dense, membrane-limited lipid vacuoles in the cytoplasm. After 14 months, neither spontaneous regression nor anetoderma-like scars were noted. Our immunohistochemical and ultrastructural studies support the notion that the origin of the foamy cells is the macrophage rather than the factor XIIIa (+) dermal dendrocyte. There was no associated or underlying disease in this case. We suggest the term primary PX for cases such as this one.
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PMID:Primary papular xanthoma of children: a clinicopathologic, immunohistopathologic and ultrastructural study. 941 17


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