Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06126 (CD1a)
 2,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have characterized dendritic cell (DC)-associated lectin-1 (DCAL-1), a novel, type II, transmembrane, C-type lectin-like protein. DCAL-1 has restricted expression in hemopoietic cells, in particular, DCs and B cells, but T cells and monocytes do not express it. The DCAL-1 locus is within a cluster of C-type lectin-like loci on human chromosome 12p12-13 just 3' to the CD69 locus. The consensus sequence of the DCAL-1 gene was confirmed by RACE-PCR; however, based on sequence alignment with genomic DNA and with various human expressed sequence tags, we predict that DCAL-1 has two splice variants. C-type lectins share a common sequence motif of 14 invariable and 18 highly conserved aa residues known as the carbohydrate recognition domain. DCAL-1, however, is missing three of the cysteine residues required to form the standard carbohydrate recognition domain. DCAL-1 mRNA and protein expression are increased upon the differentiation of monocytes to CD1a(+) DCs. B cells also express high levels of DCAL-1 on their cell surface. Using a DCAL-1 fusion protein we identified a population of CD4(+) CD45RA(+) T cells that express DCAL-1 ligand. Coincubation with soluble DCAL-1 enhanced the proliferation of CD4(+) T cells in response to CD3 ligation and significantly increased IL-4 secretion. In contrast, coincubation with soluble DC-specific ICAM-3-grabbing nonintegrin (CD209) fusion protein as a control had no effect on CD4(+) T cell proliferation or IL-4 and IFN-gamma secretion. Therefore, the function of DCAL-1 on DCs and B cells may act as a T cell costimulatory molecule, which skews CD4(+) T cells toward a Th2 response by enhancing their secretion of IL-4.
 ...
PMID:Dendritic cell-associated lectin-1: a novel dendritic cell-associated, C-type lectin-like molecule enhances T cell secretion of IL-4. 1242 43

Mannan-binding lectin (MBL) is a collectin synthesized by the liver and secreted into the bloodstream. It has a receptor for microbial structures in its C-type lectin domain and a separate receptor(s) located within its collagen-like region for autologous phagocytic cells. Here we demonstrate that human peripheral blood adherent cells (monocytes) and monocyte-derived dendritic cells are a source of MBL, and that a novel calcium-dependent and sugar-specific MBL receptor is up-regulated in immature (CD1a-positive) dendritic cells. These findings suggest a previously unsuspected autologous function for MBL, perhaps a regulatory role within the immune system.
 ...
PMID:Immature dendritic cells possess a sugar-sensitive receptor for human mannan-binding lectin. 1280 81

The diagnosis of pulmonary Langerhans cell histiocytosis might be refined by demonstrating reliability of a new cell marker, i.e., Langerin (CD207), used on bronchoalveolar lavage fluid. For this purpose, we collected material from patients with this disease and also with sarcoidosis and idiopathic pulmonary fibrosis as controls. In addition to the immunocytochemical detection of Langerin, we examined the expression profiles of CD1a and the macrophage tandem-repeat mannose receptor (CD206). To test accessibility of Langerin, a C-type lectin, for mannosides, we employed reverse lectin histochemistry using mannose-containing neoglycoproteins. The analysis revealed a significantly increased percentage of CD1a- and Langerin-positive cells in pulmonary Langerhans cell histiocytosis in comparison with both other studied diseases. No expression of the 175-kDa mannose-binding lectin (CD206) in Langerhans cells was observed. Evidently, binding sites on the cells were not accessible for the mannose-containing neoglycoligand. These results provide evidence for the usefulness of Langerin-directed immuno- and glycohistochemical monitoring of bronchoalveolar lavage fluid in the diagnosis of pulmonary Langerhans cell histiocytosis.
 ...
PMID:Diagnostic relevance of Langerin detection in cells from bronchoalveolar lavage of patients with pulmonary Langerhans cell histiocytosis, sarcoidosis and idiopathic pulmonary fibrosis. 1472 67

Langerhans cells (LCs) constitute a subset of DCs that initiate immune responses in skin. Using leprosy as a model, we investigated whether expression of CD1a and langerin, an LC-specific C-type lectin, imparts a specific functional role to LCs. LC-like DCs and freshly isolated epidermal LCs presented nonpeptide antigens of Mycobacterium leprae to T cell clones derived from a leprosy patient in a CD1a-restricted and langerin-dependent manner. LC-like DCs were more efficient at CD1a-restricted antigen presentation than monocyte-derived DCs. LCs in leprosy lesions coexpress CD1a and langerin, placing LCs in position to efficiently present a subset of antigens to T cells as part of the host response to human infectious disease.
 ...
PMID:Langerhans cells utilize CD1a and langerin to efficiently present nonpeptide antigens to T cells. 1499 Oct 60

Myeloid dendritic cells (MyDCs), prime stimulators of antigen-specific immunity, can serve as one of the major reservoirs for human immunodeficiency virus type-1 (HIV-1). Utilizing mature monocyte-derived MyDCs generated with granulocyte/macrophage colony-stimulating factor, interleukin-4, and tumour necrosis factor-alpha as an in vitro model, we here present the first proof of concept for liposomal compound delivery to these cells by specifically addressing CD209, i.e. DC-specific intercellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN), a MyDC-associated C-type lectin implicated in the transmission of HIV-1 to T helper cells. By employing a liposomally entrapped tracer, calcein, we demonstrate by flow cytometry and mathematics a superior targeting efficacy for DC-SIGN, as compared with select other MyDC markers (CD1a, CD4, CD45R0, and CD83). Fluorescence microscopy reveals time-dependent surface binding and intracellular uptake of DC-SIGN-specific liposomes by both immature and mature MyDCs. This pilot study implies that liposomal targeting to CD209 and related C-type lectins may afford therapeutic intracellular drug delivery to MyDCs and other reservoir and nonreservoir cells susceptible to infection with HIV-1.
 ...
PMID:DC-SIGN-specific liposomal targeting and selective intracellular compound delivery to human myeloid dendritic cells: implications for HIV disease. 1514 50

Langerin is a type II transmembrane C-type lectin associated with the formation of Birbeck granules in Langerhans cells. Langerin is a highly selective marker for Langerhans cells and the lesional cells of Langerhans cell histiocytosis. Although Langerin protein expression in Langerhans cell histiocytosis has been previously documented, the specificity of Langerin expression as determined by immunohistochemistry in the context of other histiocytic disorders has not been well established. In the present study, Langerin immunoreactivity was examined in a series of histiocytic disorders of monocyte/macrophage and dendritic cell derivation to assess the specificity and utility of Langerin as a diagnostic marker for Langerhans cell histiocytosis. Immunohistochemical expression of CD1a was also evaluated for comparison. Seventeen cases of Langerhans cell histiocytosis and 64 cases of non-Langerhans cell histiocytic disorders were examined. Langerin and CD1a were uniformly expressed in all cases of Langerhans cell histiocytosis, with the exception of one case that was positive for Langerin and negative for CD1a. Among the non-Langerhans cell histiocytic disorders evaluated, focal Langerin immunoreactivity was observed only in 2 of 10 cases of histiocytic sarcoma. All non-Langerhans cell histiocytic disorders showed no expression of CD1a. Langerin expression seems to be a highly sensitive and relatively specific marker of Langerhans cell histiocytosis. Immunohistochemical evaluation of Langerin expression may have utility in substantiating a diagnosis of Langerhans cell histiocytosis and separating this disorder from other non-Langerhans cell histiocytic proliferations.
 ...
PMID:Immunohistochemical expression of Langerin in Langerhans cell histiocytosis and non-Langerhans cell histiocytic disorders. 1827 80

MBL (mannan-binding lectin; also called mannose-binding lectin) is a circulating C-type lectin with a collagen-like region synthesized mainly by the liver. MBL may influence susceptibility to infection in recipients of stem cell transplants, and it has even been suggested that the MBL status of a donor can influence the recipient's susceptibility to post-transplant infections. We have previously reported that MBL can be detected on human monocytes and monocyte-derived dendritic cells, based on detection using biotinylated anti-MBL, suggesting that those cells could synthesize MBL. If true, permanent MBL replacement therapy could be achieved by stem cell infusions. However, two other groups independently failed to find mbl-2-derived mRNA in monocytes. Therefore, to confirm or refute our previous observations, we used an alternative experimental strategy. Instead of using biotinylated antibody and labelled streptavidin, detection of surface MBL was attempted using MBL-specific primary antibodies (131-1, 131-10 and 131-11) followed by fluorescein-labelled anti-IgG, and controlled by the use of non-specific IgG as primary antibody. Monocytes were counterstained with anti-CD14-PE before FACS analysis. Adherent monocytes were also cultured for 48 h in serum-free medium or converted into immature dendritic cells by culture with IL-4 (interleukin-4) and GM-CSF (granulocyte/monocyte colony-stimulating factor). During FACS analysis, the dendritic cells were gated after counter-staining with anti-CD1a-PE. MBL was readily detected on the surface of fresh monocytes using all three specific anti-MBL monoclonal antibodies, but specific anti-MBL binding was greatly diminished after monocytes had been cultured for 2 days in serum-free medium. Moreover, we could not detect any MBL present on the surface of monocyte-derived dendritic cells. We therefore conclude that MBL is indeed present on the surface of fresh human monocytes. However, in view of the mRNA findings of others and our own previous observation that no secretion of MBL took place in culture, we presume that the surface-bound MBL is derived from autologous plasma and not synthesized by the cells. This conclusion is consistent with our in vivo findings in stem cell transplant patients which provided evidence against significant extra-hepatic production of serum MBL. It provides no ready explanation for the remarkable observation of Mullighan, Heatley, Doherty, Szabo, Grigg, Hughes, Schwarer, Szer, Tait, Bik To and Bardy [(2002) Blood 99, 3524-3529] that the presence of variant alleles of mbl-2 in stem cell donors can influence susceptibility to serious infections in their recipients.
 ...
PMID:Is mannan-binding lectin (MBL) detectable on monocytes and monocyte-derived immature dendritic cells? 1902 83

Langerhans cells (LCs) are the main population of antigen-presenting cells lining the epidermis and stratified mucosal epithelia (1). Therefore, they play an important role in the first line of defense against invading pathogens. Upon capture of these pathogens, LCs subsequently migrate to the lymph nodes where they present pathogen-derived antigens to T cells to initiate an adaptive immune response. During this migration, LCs up-regulate cell surface marker HLA-DR and co-stimulatory molecules, while the LC-specific C-type lectin Langerin is down-regulated (reviewed in Refs. (2,3)). In the epidermis, LCs are the only cell population expressing CD1a and this marker is therefore extremely useful to isolate LCs from epidermis (4). Here we discuss a method to isolate human primary LCs from the epidermis in an as immature state as possible. The use of immature LCs is especially important in the investigation of the function of these cells, since few acceptable LC models are available. Immature LCs can be used to further elucidate the function of LCs in pathogen interactions and adaptive immunity.
 ...
PMID:Isolation of immature primary Langerhans cells from human epidermal skin. 1994 Nov 5

Using the zinc-iodide osmium tetroxide (ZIO) method, TEM and immunohistochemistry (for CD1a and langerin), the study demonstrates Langerhans cells in the oesophageal epithelium of domesticated mammals (herbivores: horse, cattle, goat; omnivores: pig, dog, laboratory rat; carnivores: cat), although with variations between the species. The ZIO method and TEM showed this cell type in the cat and, sporadically, in the horse; CD1a (+) Langerhans cells were demonstrated in the ovine, porcine and murine oesophagus. Positive staining for langerin was detected in single cells of the caprine, canine, murine and feline oesophagus and more distinct in almost all the cell layers of the equine and porcine oesophagus epithelium. The findings are discussed comparing specifically the results for CD1a and langerin, whereby the latter C-type lectin may be of importance in species with a rather thick oesophagus epithelium, such as that present in the plantivorous and most of the omnivorous animals, where antigenic pressure is reduced.
 ...
PMID:A note on langerhans cells in the oesophagus epithelium of domesticated mammals. 2008 69

A biological explanation for the reduction in HIV-1 (HIV) acquisition after male circumcision may be that removal of the foreskin reduces the number of target cells for HIV. The expression of potential HIV target cells and C-type lectin receptors in foreskin tissue of men at risk of HIV infection were thus analyzed. Thirty-three foreskin tissue samples, stratified by Herpes simplex virus type 2 status, were obtained from a randomized, controlled trial conducted in Kenya. The samples were analyzed by confocal in situ imaging microscopy and mRNA quantification by quantitative RT-qPCR. The presence and location of T cells (CD3(+)CD4(+)), Langerhans cells (CD1a(+)Langerin/CD207(+)), macrophages (CD68(+) or CD14(+)), and submucosal dendritic cells (CD123(+)BDCA-2(+) or CD11c(+)DC-SIGN(+)) were defined. C-type lectin receptor expressing cells were detected in both the epithelium and submucosa, and distinct lymphoid aggregates densely populated with CD3(+)CD4(+) T cells were identified in the submucosa. Although the presence of lymphoid aggregates and mRNA expression of selected markers varied between study subjects, Herpes simplex virus type 2 serostatus was not the major determinant for the detected differences. The detection of abundant and superficially present potential HIV target cells and submucosal lymphoid aggregates in foreskin mucosa from a highly relevant HIV risk group demonstrate a possible anatomical explanation that may contribute to the protective effect of male circumcision on HIV transmission.
 ...
PMID:Abundant expression of HIV target cells and C-type lectin receptors in the foreskin tissue of young Kenyan men. 2039 32


1 2 Next >>