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1.
Water Resour Res ; 53(6): 5158-5165, 2017 06.
Article in English | MEDLINE | ID: mdl-28931957

ABSTRACT

Snow measurements at the Kühtai station in Tirol, Austria, (1920 m.a.s.l.) are described. The data set includes snow water equivalent from a 10 m2 snow pillow, snow melt outflow from a 10 m2 snow lysimeter placed at the same location as the pillow, meteorological data (precipitation, incoming shortwave radiation, reflected shortwave radiation, air temperature, relative air humidity, and wind speed), and other data (snow depths, snow temperatures at seven heights) from the period October 1990 to May 2015. All data have been quality checked, and gaps in the meteorological data have been filled in. The data set is unique in that all data are available at a temporal resolution of 15 min over a period of 25 years with minimal changes in the experimental setup. The data set can therefore be used to analyze snow pack processes over a long-time period, including their extremes and long-term changes, in an Alpine climate. Analyses may benefit from the combined measurement of snow water equivalent, lysimeter outflow, and precipitation at a wind-sheltered alpine site. An example use of data shows the temporal variability of daily and 1 April snow water equivalent observed at the Kühtai site. The results indicate that the snow water equivalent maximum varies between 200 and more than 500 mm w.e., but there is no statistically significant temporal trend in the period 1990-2015.

2.
Tidsskr Nor Laegeforen ; 120(3): 364-6, 2000 Jan 30.
Article in Norwegian | MEDLINE | ID: mdl-10827530

ABSTRACT

Cytologic examination of the body cavity effusions in patients with ovarian tumours is performed to differentiate between reactive processes and tumour spread. While detection of malignant cells is a marker of metastatic disease and a sign of bad prognosis, benign effusions affect neither disease stage nor the patient's prognosis. Determination of the presence or absence of tumour spread is based primarily on cellular morphology. As distinction between reactive mesothelial and cancer cells can be difficult, immunocytochemistry may be employed in equivocal cases. The case of a 42-year-old woman who presented with a large pelvic mass accompanied by ascites and hydrothorax is described. Cytomorphology of preoperative pleural fluid specimen was inconclusive. Immunocytochemical examination of cell block sections using: BerEP4, B72.3, CA 125, CD15, CEA, E-cadherin and calretinin was done. No epithelial cells were detected and diagnosis of reactive mesothelial cells was made. Laparotomy was performed and adnexal tumour removed. Borderline mucinous tumour of the ovary was diagnosed. There was no recurrence of the ascites or hydrothorax. The clinicopathologic features and terminology of pseudo-Meigs' syndrome are briefly reviewed. The role of ancillary studies in diagnosis of body cavity effusions is emphasized.


Subject(s)
Meigs Syndrome , Adult , Cystadenoma, Mucinous/immunology , Cystadenoma, Mucinous/pathology , Diagnosis, Differential , Female , Humans , Meigs Syndrome/immunology , Meigs Syndrome/pathology , Ovarian Neoplasms/immunology , Ovarian Neoplasms/pathology , Ovary/pathology , Pleural Effusion, Malignant/immunology , Pleural Effusion, Malignant/pathology
3.
J Exp Med ; 190(7): 915-22, 1999 Oct 04.
Article in English | MEDLINE | ID: mdl-10510081

ABSTRACT

Mucosal surfaces are protected specifically by secretory immunoglobulin A (SIgA) and SIgM generated through external translocation of locally produced dimeric IgA and pentameric IgM. Their active transport is mediated by the epithelial polymeric Ig receptor (pIgR), also called the transmembrane secretory component. Paracellular passive external transfer of systemic and locally produced antibodies also provides mucosal protection, making the biological importance of secretory immunity difficult to assess. Here we report complete lack of active external IgA and IgM translocation in pIgR knockout mice, indicating no redundancy in epithelial transport mechanisms. The knockout mice were of normal size and fertility but had increased serum IgG levels, including antibodies to Escherichia coli, suggesting undue triggering of systemic immunity. Deterioration of their epithelial barrier function in the absence of SIgA (and SIgM) was further attested to by elevated levels of albumin in their saliva and feces, reflecting leakage of serum proteins. Thus, SIgA did not appear to be essential for health under the antigen exposure conditions of these experimental animals. Nevertheless, our results showed that SIgA contributes to maintenance of mucosal homeostasis. Production of SIgA might therefore be a variable in the initiation of human immunopathology such as inflammatory bowel disease or gluten-sensitive enteropathy.


Subject(s)
Immunoglobulin A, Secretory/metabolism , Intestinal Mucosa/immunology , Receptors, Polymeric Immunoglobulin/genetics , Receptors, Polymeric Immunoglobulin/immunology , Animals , Antibodies, Bacterial/blood , Biological Transport , Biological Transport, Active , Escherichia coli/immunology , Fertility , Glutens/immunology , Humans , Immunoglobulin G/blood , Immunoglobulin M/metabolism , Intestine, Small/immunology , Lactobacillus/immunology , Mice , Mice, Inbred C57BL , Mice, Inbred Strains , Mice, Knockout , Rats , Receptors, Polymeric Immunoglobulin/deficiency , Restriction Mapping , Saliva/immunology , Serum Albumin/metabolism
4.
Eur J Immunol ; 29(10): 3401-9, 1999 10.
Article in English | MEDLINE | ID: mdl-10540352

ABSTRACT

The human polymeric Ig receptor (pIgR), or transmembrane secretory component, is basolaterally expressed on secretory epithelial cells; its function is to transport externally J chain-containing dimeric IgA and pentameric IgM. The ligand-binding extracellular part of this receptor contains five disulfide-stabilized domains which show considerable homology with the variable domains of Ig chains. The N-terminal domain 1 (D1) mediates the initial noncovalent ligand interaction. In this study we made deletions of the human pIgR D2 and D3 (pIgRDelta2,3), or D4 and D5 (pIgRDelta4,5), to investigate the influence of these domains in receptor binding and transport of dimeric IgA and pentameric IgM across MDCK cells transfected with the truncated receptors. Both mutants were found to bind pentameric IgM, but only pIgRDelta4,5 bound dimeric IgA. These results showed that the two ligands interact differently with human pIgR; binding of pentameric IgM apparently depends fully on strong interactions with D1, while binding of dimeric IgA in addition depends on elements within D2 and / or D3 to support the initial noncovalent binding to D1. Moreover, our studies imply that dimeric human IgA binds differently to pIgR from various species. This observation cautions against interpretation of functional studies performed with non-homologous receptor-ligand pairs.


Subject(s)
Immunoglobulin M/genetics , Peptide Fragments/genetics , Receptors, Polymeric Immunoglobulin/genetics , Sequence Deletion , Animals , Binding Sites, Antibody/genetics , Cells, Cultured , Dimerization , Dogs , Humans , Immunoglobulin A/metabolism , Immunoglobulin M/biosynthesis , Immunoglobulin M/metabolism , Kidney/metabolism , Mutation/genetics , Peptide Fragments/immunology , Peptide Fragments/metabolism , Receptors, Polymeric Immunoglobulin/biosynthesis , Receptors, Polymeric Immunoglobulin/metabolism , Transfection
5.
Eur J Immunol ; 29(1): 168-79, 1999 01.
Article in English | MEDLINE | ID: mdl-9933098

ABSTRACT

The transmembrane secretory component (SC, or pIg receptor) plays a crucial role in mucosal immunity by translocating dimeric IgA and pentameric IgM through exocrine epithelia. This receptor is up-regulated by cytokines in parallel with increased epithelial HLA expression. By use of the human epithelial cell line HT-29m3, we show that IFN-gamma, TNF-alpha and IL-4 activate transcription of the SC gene. This activation was slow, suggesting mediation via newly synthesized protein factors. IFN-gamma and TNF-alpha, but not IL-4, also up-regulated expression of HLA class I genes. However, this gene induction was rapid and did not depend on new protein synthesis. Nuclear run-on experiments showed that the transcription rate of HLA class I genes nearly peaked after only 30 min of IFN-gamma or TNF-alpha stimulation, whereas the SC transcription rate did not peak until after 20-36 h of IFN-gamma, TNF-alpha or IL-4 stimulation. Gel electrophoresis mobility shift assays demonstrated binding of nuclear proteins from cytokine-stimulated HT-29 cells to consensus elements in the promoter of the SC gene, involving the binding site for the nuclear factor-kappaB p50 subunit after TNF-alpha stimulation, and IFN-stimulated response element after IFN-gamma stimulation (and weakly after TNF-alpha. Our observations in vitro likely parallel events in vivo by which activated mucosal T cells and macrophages enhance pIg receptor-mediated external transport of secretory IgA and IgM and up-regulate epithelial HLA expression.


Subject(s)
Cytokines/pharmacology , Genes, MHC Class I/drug effects , Histocompatibility Antigens Class I/biosynthesis , Secretory Component/biosynthesis , Secretory Component/genetics , Base Sequence , Cell Line , Cycloheximide/pharmacology , DNA Probes/genetics , Dichlororibofuranosylbenzimidazole/pharmacology , Enzyme Inhibitors/pharmacology , Epithelial Cells/drug effects , Epithelial Cells/immunology , Gene Expression Regulation/drug effects , Humans , Interferon-gamma/pharmacology , Interleukin-4/pharmacology , Protein Synthesis Inhibitors/pharmacology , RNA Polymerase II/antagonists & inhibitors , RNA, Messenger/genetics , RNA, Messenger/metabolism , Recombinant Proteins , Transcriptional Activation , Tumor Necrosis Factor-alpha/pharmacology
6.
Eur J Immunol ; 28(4): 1161-71, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9565355

ABSTRACT

The polymeric immunoglobulin receptor (pIgR), which is constitutively expressed on the basolateral surface of secretory epithelial cells, mediates external translocation of polymeric IgA and pentameric IgM (collectively called pIg) to exocrine secretions. A high level of synthesis must be maintained because the receptor is continuously cleaved to release bound secretory component (SC) in secretory IgA and secretory IgM, as well as free SC from unoccupied receptor. We have isolated the promoter of the pIgR gene and identified a short activating region that is required for the expression of pIgR promoter-driven reporter genes. This region contained an E-box and an inverted repeat sequence (IRS). Gel electrophoresis mobility shift assays with nuclear extracts from different pIgR-expressing epithelial cell lines demonstrated proteins that bind independently to both the E-box and the IRS sequence of the pIgR promoter. In addition, a DNA probe that contained both the E-box and the IRS gave rise to a larger complex that could not be competed by either element on its own. Binding was confirmed by DNase I footprinting of the E-box and IRS sequences with nuclear extracts, and by dimethyl sulfide footprinting in living HT-29 epithelial cells. Finally, a mutation in the pIgR promoter that inhibited protein binding to the E-box and the formation of the larger complex, abolished activated transcription from the reporter gene.


Subject(s)
DNA/genetics , Genome, Human , Promoter Regions, Genetic/genetics , Receptors, Polymeric Immunoglobulin/genetics , Base Sequence , Cell Line , Gene Expression Regulation , Humans , Molecular Sequence Data , Receptors, Polymeric Immunoglobulin/biosynthesis , Receptors, Polymeric Immunoglobulin/immunology
7.
Hum Mol Genet ; 6(7): 1125-35, 1997 Jul.
Article in English | MEDLINE | ID: mdl-9215684

ABSTRACT

Dystrophic epidermolysis bullosa (EBD) is a clinically heterogeneous skin disorder, characterized by abnormal anchoring fibrils (AF) and loss of dermal-epidermal adherence. EBD has been linked to the COL7A1 gene at chromosome 3p21 which encodes collagen VII, the major component of the AF. Here we investigated two unrelated EBD families with different clinical phenotypes and novel combinations of recessive and dominant COL7A1 mutations. Both families shared the same recessive heterozygous 14 bp deletion at the exon-intron 115 boundary of the COL7A1 gene. The deletion caused in-frame skipping of exon 115 and the elimination of 29 amino acid residues from the pro-alpha1(VII) polypeptide chain. As a result, procollagen VII was not converted to collagen VII and the C-terminal NC-2 propeptide which is normally removed from the procollagen VII prior to formation of the anchoring fibrils was retained in the skin. All affected individuals also carried missense mutations in exon 73 of COL7A1 which lead to different glycine-to-arginine substitutions in the triple-helical domain of collagen VII. Combination of the deletion mutation with a G2009R substitution resulted in a mild phenotype. In contrast, combination of the deletion with a G2043R substitution led to a severe phenotype. The G2043R substitution was a de novo mutation which alone caused a mild phenotype. Thus, different combinations of dominant and recessive COL7A1 mutations can modulate disease activity of EBD and alter the clinical presentation of the patients.


Subject(s)
Collagen/genetics , Epidermolysis Bullosa Dystrophica/genetics , Mutation , Adolescent , Adult , Alleles , Child , Collagen/immunology , Collagen/metabolism , Epidermolysis Bullosa Dystrophica/pathology , Female , Fluorescent Antibody Technique, Indirect , Genes, Dominant , Genes, Recessive , Haplotypes , Humans , Infant , Infant, Newborn , Male , Microscopy, Electron , Middle Aged , Molecular Sequence Data , Pedigree , RNA Splicing , Sequence Deletion , Skin/pathology
8.
Br J Cancer ; 73(12): 1503-10, 1996 Jun.
Article in English | MEDLINE | ID: mdl-8664120

ABSTRACT

Secretary component (SC) is expressed basolaterally as a transmembrane protein (pIg receptor) on secretory epithelial cells. As pIg receptor it plays a central role in humoral immunity by mediating the external translocation of dimeric IgA and pentameric IgM. A few case reports have suggested that reduced or absent SC protein expression is associated with diarrhoeal disease, but there is no convincing evidence that a primary pIg receptor deficiency can occur. In this study the relative presence of SC mRNA was determined by Northern blot analysis and related to immunohistochemically determined SC protein expression in 33 colorectal adenomas (31 patients) with increased risk of developing sporadic colorectal cancer, as well as in 19 colorectal carcinomas from 19 patients with such sporadic tumours. In the adenomas, SC mRNA levels were positively related to SC protein expression; both mRNA and SC protein were negatively related to histological grade. Similarly, SC mRNA levels tended to be related to the SC protein expression in the carcinomas. SC mRNA was detected in all adenomas, and only two of ten carcinomas (10.5%) deemed to be SC deficient by immunohistochemistry also lacked SC mRNA expression, suggesting diallelic alterations in the SC-encoding gene (locus PIGR). This possibility agreed with Southern blot analysis performed on a separate sample of 32 other colonic carcinomas in which the diallelic loss of D1S58 (which exhibits a close linkage centromerically to PIGR) was calculated to be 6.4%. Together these findings suggested that reduced SC protein expression in colorectal adenomas might be a transcriptional defect reflecting the degree of cellular dysplasia, whereas absent SC protein expression in colorectal carcinomas might also involve post-transcriptional defects and occasional diallelic gene deletions representing late events in carcinogenesis.


Subject(s)
Adenoma/metabolism , Carcinoma/metabolism , Colorectal Neoplasms/metabolism , RNA, Messenger/metabolism , Secretory Component/biosynthesis , Adenoma/genetics , Adenoma/pathology , Aged , Aged, 80 and over , Alleles , Blotting, Southern , Carcinoma/genetics , Carcinoma/pathology , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Female , Fluorescent Antibody Technique , Humans , Male , Middle Aged , Polymorphism, Restriction Fragment Length , RNA, Messenger/genetics , Secretory Component/genetics
9.
Gut ; 37(6): 766-76, 1995 Dec.
Article in English | MEDLINE | ID: mdl-8537046

ABSTRACT

Coeliac disease is precipitated in susceptible subjects by ingestion of wheat gluten or gluten related prolamins from some other cereals. The disease is strongly associated with certain HLA-DQ heterodimers, for example, DQ2 (DQ alpha 1*0501, beta 1*0201) in most patients and apparently DQ8 (DQ alpha 1*0301, beta 1*0302) in a small subset. Gluten specific T cell clones (TCC) from coeliac intestinal lesions were recently established and found to be mainly restricted by HLA-DQ2 or HLA-DQ8. Antigen induced production of cytokines was studied in 15 TCC from three patients, 10 being DQ2 and five DQ8 restricted. Cell culture supernatants were prepared by stimulation with gluten peptides in the presence of DQ2+ or DQ8+ Epstein-Barr virus transformed B cells as antigen presenting cells (APC). Supernatants were analysed for cytokines by bioassays, ELISA, and CELISA. Cellular cytokine mRNA was analysed semi-quantitatively by slot blotting and polymerase chain reaction (PCR). All TCC were found to secrete interferon (IFN) gamma, often at high concentrations (> 2000 U/ml); some secreted in addition interleukin (IL) 4, IL 5, IL 6, IL 10, tumour necrosis factor (TNF), and transforming growth factor (TGF) beta. The last TCC thus displayed a Th0-like cytokine pattern. However, other TCC produced IFN gamma and TNF but no IL 4, or IL 5, compatible with a Th1-like pattern. In conclusion, most DQ8 restricted TCC seemed to fit with a Th0 profile whereas the DQ2 restricted TCC secreted cytokines more compatible with a Th1 pattern. The TCC supernatants induced upregulation of HLA-DR and secretory component (poly-Ig receptor) in the colonic adenocarcinoma cell line HT-29.E10, most probably reflecting mainly the high IFN gamma concentrations. This cytokine, particularly in combination with TNF alpha, might be involved in several pathological features of the coeliac lesion. The characterised cytokine profiles thus support the notion that mucosal T cells activated in situ by gluten in a DQ restricted fashion play a central part in the pathogenesis of coeliac disease.


Subject(s)
Celiac Disease/metabolism , Cytokines/biosynthesis , Glutens/immunology , Intestinal Mucosa/immunology , T-Lymphocyte Subsets/immunology , Base Sequence , Celiac Disease/immunology , Enzyme-Linked Immunosorbent Assay , HLA-DQ Antigens/analysis , Humans , Interferon-gamma/biosynthesis , Interleukins/biosynthesis , Molecular Sequence Data , Polymerase Chain Reaction , Transforming Growth Factor beta/biosynthesis , Tumor Necrosis Factor-alpha/biosynthesis
11.
DNA Cell Biol ; 14(3): 251-6, 1995 Mar.
Article in English | MEDLINE | ID: mdl-7880445

ABSTRACT

The polymeric immunoglobulin receptor (transmembrane secretory component) mediates transcellular transport of dimeric immunoglobulin A (IgA) and pentameric IgM in glandular and mucosal epithelial cells. cDNAs encoding two forms of the bovine polymeric immunoglobulin receptor (pIgR) have been cloned and sequenced. The long form contains 3,527 bp and predicts a single open reading frame of 2,271 bp encoding a protein of 757 bp. The extracellular part contains five immunoglobulin (Ig)-like domains. The shorter form lacks the region from residues 458-1,111 corresponding to Ig-like domains 2 and 3. In Northern blot analysis of various bovine tissues, only the long form of pIgR mRNA was detected. By using the reverse transcription-polymerase chain reaction (RT-PCR), both forms were detected. An alignment of the cytoplasmic tail of the pIgR from bovine, human, rabbit, and rat revealed highly conserved areas that may reflect the importance of these regions for intracellular sorting of the receptor.


Subject(s)
Cloning, Molecular , Secretory Component/genetics , Amino Acid Sequence , Animals , Base Sequence , Blotting, Northern , Cattle , DNA, Complementary/chemistry , DNA, Complementary/genetics , Humans , Molecular Sequence Data , Molecular Weight , Open Reading Frames , Polymerase Chain Reaction , Rabbits , Rats , Secretory Component/chemistry , Sequence Alignment
15.
Scand J Immunol ; 37(2): 251-6, 1993 Feb.
Article in English | MEDLINE | ID: mdl-8434236

ABSTRACT

Secretory component (SC or poly-Ig receptor) plays a key role in mucosal external body fluids. The aim of this study was to elucidate the molecular events underlying IFN-gamma-dependent up-regulation of SC. Using a human SC cDNA clone isolated by our laboratory, we found that IFN-gamma up-regulated SC mRNA levels in a time- and concentration-dependent manner. Moreover, in situ hybridization showed a striking increase of SC mRNA-positive HT-29 cells after IFN-gamma treatment. Inhibition with 5,6-dichloro-1-beta-ribofuranosyl-benzimidazole (DRB) indicated a half-life for IFN-gamma-induced SC mRNA of approximately 1 h. Cycloheximide (CHX) abolished the IFN-gamma-induced accumulation of SC mRNA in a reversible manner; the time-course suggested that de novo synthesis of protein factor(s) with a turnover time shorter than 6 h was required for accumulation of SC message. IFN-gamma-stimulated up-regulation of SC expression therefore appears to depend on molecular events similar to those taking place for the activation of several other genes in the Ig supergene family.


Subject(s)
Interferon-gamma/pharmacology , RNA, Messenger/drug effects , Secretory Component/genetics , Colonic Neoplasms/genetics , Cycloheximide/pharmacology , Dactinomycin/pharmacology , Dichlororibofuranosylbenzimidazole/pharmacology , Humans , Secretory Component/physiology , Time Factors , Tumor Cells, Cultured , Up-Regulation/drug effects
16.
Hum Genet ; 90(3): 215-9, 1992 Nov.
Article in English | MEDLINE | ID: mdl-1487233

ABSTRACT

The human transmembrane secretory component (SC or poly-Ig receptor, PIGR) is expressed basolaterally on glandular epithelial cells and is responsible for the external translocation of polymeric IgA and IgM. SC is hence a key molecule in antibody protection of mucosal surfaces. The human SC gene (locus PIGR) is located on chromosome 1 (1q31-q41). Here we present the first genetic linkage study of PIGR versus syntenic markers, including D1S58 and F13B, which have been previously regionalized to 1q31-q32 and 1q31-q32.1, respectively. We found that PIGR is closely linked to D1S58 (lods + 5.06 at theta max = 0.06, without sex difference). PIGR versus F13B showed + 1.46 at theta max = 0.25 for both sexes combined. A recombination of 0.06 between F13B and D1S58 (lods + 2.24) was in contrast to a previously published study giving theta max = 0.22 (lods + 3.9), the combined lods being 5.6 at theta max = 0.20. The progeny of a triply heterozygotic female indicated that PIGR is the flanking locus, therefore suggesting a cen-F13B-D1S58-PIGR-qter gene sequence on human chromosome 1. Only negative lod scores to RH, C8@, and PGM1 on 1p, and FY on proximal 1q, were found. Current combined Norwegian allele frequencies were estimated for PIGR to be A1 = 0.63, A2 = 0.37 (370 chromosomes), and for D1S58 to be A1 = 0.44, A2 = 0.56 (218 chromosomes).


Subject(s)
Chromosomes, Human, Pair 1 , Membrane Glycoproteins/genetics , Secretory Component/genetics , Chromosome Mapping , Female , Genetic Linkage , Heterozygote , Humans , Lod Score , Male , Receptors, Immunologic
17.
Genomics ; 14(1): 63-9, 1992 Sep.
Article in English | MEDLINE | ID: mdl-1358799

ABSTRACT

The genes encoding the regulatory subunits RI beta (locus PRKAR1B) and RII beta (locus PRKAR2B) of human cAMP-dependent protein kinase have been mapped in the basic CEPH (Centre d'Etude du Polymorphisme Humain) family panel of 40 families to chromosome 7p and 7q, respectively, using the enzymes HindIII and BanII recognizing the corresponding restriction fragment length polymorphisms (RFLPs). Previous data from the CEPH database and our present RFLP data were used to construct a six-point local framework map including PRKAR1B and a seven-point framework map including PRKAR2B. The analysis placed PRKAR1B as the most distal of the hitherto mapped 7p marker loci and resulted in an unequivocal order of pter-PRKAR1B-D7S21-D7S108-D7S17-D7S149- D7S62-cen, with a significantly higher rate of male than female recombination between PRKAR1B and D7S21. The 7q regulatory gene locus, PRKAR2B, could also be placed in an unambigous order with regard to the existing CEPH database 7q marker loci, the resulting order being cen-D7S371-(COL1A2,D7S79)-PRKAR2B-MET-D7S87++ +-TCRB-qter. Furthermore, in situ hybridization to metaphase chromosomes physically mapped PRKAR2B to band q22 on chromosome 7.


Subject(s)
Chromosome Mapping , Chromosomes, Human, Pair 7 , Genes, Regulator/genetics , Protein Kinases/genetics , Female , Genetic Linkage , Genetic Markers , Humans , Lod Score , Male , Nucleic Acid Hybridization , Polymorphism, Restriction Fragment Length , Recombination, Genetic
18.
Eur J Immunol ; 22(9): 2309-15, 1992 Sep.
Article in English | MEDLINE | ID: mdl-1355431

ABSTRACT

Secretory component (SC or the poly-Ig receptor) plays a crucial role in mucosal immunity by translocating polymeric IgA and IgM through secretory epithelial cells into external body fluids. Labeled restriction fragments from human SC cDNA were used to screen a human genomic leukocyte library. Three overlapping clones, spanning a total of 19 kb of the human SC gene, including 3 kb of the 5' flanking region, were characterized. The putative TATA box candidate, preceded by a CAAT-like box, was found 329 nucleotides upstream of the first exon. Altogether 11 exons covering the entire coding region were identified. The exon size ranged from 59 to 657 nucleotides and exon-intron junctions followed known consensus sequences. Three of the five extracellular Ig-related domains (D1, D4 and D5) were confined to one exon each (E3, E5 and E6), whereas D2 and D3 were encoded by the same exon (E4). The latter exon corresponds to that involved in alternate splicing of rabbit SC. The membrane-spanning segment was confined to part of one exon (E8). The cytoplasmic tail was encoded by four exons (E8-E11), whose boundaries encompassed fairly well the structural determinants proposed to be responsible for intracellular sorting of SC in the rabbit. The polymorphic restriction site reported earlier for Pvu II was localized to the third intron.


Subject(s)
Cloning, Molecular , Exons , Introns , Secretory Component/genetics , Amino Acid Sequence , Base Sequence , Humans , Molecular Sequence Data , Polymorphism, Restriction Fragment Length
19.
Scand J Immunol ; 35(6): 669-76, 1992 Jun.
Article in English | MEDLINE | ID: mdl-1376489

ABSTRACT

T cells and other leucocytes regularly occur within and subjacent to the gut epithelium. Recent data suggest that intestinal epithelial cells may exert accessory immunological functions. Although interactions between leucocytes and accessory cells usually require expression of adhesion molecules, intestinal epithelium has generally been considered negative for intercellular adhesion molecule-1 (ICAM-1) by immunohistochemical techniques. We therefore studied the expression of ICAM-1 and lymphocyte function-associated antigen-3 (LFA-3) by two colonic epithelial cell lines and found that both adhesion molecules were constitutively present at low levels. ICAM-1 protein expression could be enhanced within 4 h by cytokines, particularly after co-incubation with interferon-gamma (IFN) and tumour necrosis factor-alpha (TNF), interleukin-1 beta (IL-1), or IL-6. IFN also resulted in accumulation of ICAM-1 mRNA. Conversely, the LFA-3 expression was virtually unaffected by cytokine stimulation. These data imply that intestinal epithelial cells under certain conditions may bear adhesion molecules required for cooperation with juxtaposed leucocytes in situ, and that the expression of some of these molecules is modulated by cytokines from activated mucosal leucocytes.


Subject(s)
Antigens, CD/immunology , Cell Adhesion Molecules/immunology , Antigens, CD/analysis , Antigens, CD/genetics , Blotting, Northern , CD58 Antigens , Cell Adhesion Molecules/analysis , Cell Adhesion Molecules/genetics , Cytokines/pharmacology , DNA Probes , Enzyme-Linked Immunosorbent Assay , Epithelium/immunology , Epithelium/pathology , Gene Expression Regulation , Humans , Intercellular Adhesion Molecule-1 , Intestines/immunology , Intestines/pathology , Kinetics , RNA, Messenger/analysis , Tumor Cells, Cultured
20.
Ann N Y Acad Sci ; 664: 157-79, 1992.
Article in English | MEDLINE | ID: mdl-1456647

ABSTRACT

Epithelial HLA class II is differentially expressed (DR >> DP) only after birth in salivary glands and small intestinal mucosa, in contrast to class I determinants and secretory component (SC) which appear early in gestation. However, there is a brisk postnatal increase in SC expression along with the class II induction, suggesting stimulation by cytokines from activated immune cells. T lymphocytes remain quite scanty in postnatal salivary glands, and the striking SC and class II expression might reflect a synergistic effect of IFN-gamma and TFN-alpha on immature epithelial cells. Enhanced epithelial expression of both SC and class II in salivary glands from sudden infant death victims could be the effect of immunostimulation caused by an infectious agent. Strikingly upregulated SC and epithelial class II expression (DR > DP > DQ) is seen in various inflammatory lesions such as obstructive sialadenitis, Sjögren's syndrome, chronic gastritis, and celiac disease. IFN-gamma and TNF-alpha are most likely involved as the expression patterns can be reproduced with these cytokines in vitro on colonic epithelial cell lines. However, these molecules of the Ig supergene family do not show a selective response in epithelia of inflammatory lesions because increased expression is also seen for lysozyme, lactoferrin and some other proteins. ICAM-1 can be upregulated on epithelial cells by various cytokines in vitro although the situation remains uncertain in mucosal inflammation. The expression pattern in IBD is complicated by dysplastic epithelial changes leading to reduced SC levels which may thus, in turn, jeopardize the poly-Ig transport mechanism. Epithelial class II molecules appear to have antigen-presenting properties, but the immunopathologic role of their increased expression in inflammatory disease in terms of induction of autoimmunity and/or abrogation of oral tolerance is a matter of continuing dispute.


Subject(s)
Cell Adhesion Molecules/analysis , Histocompatibility Antigens Class II/analysis , Intestinal Mucosa/immunology , Secretory Component/analysis , Animals , Female , Fetus/immunology , Gastrointestinal Diseases/immunology , Humans , Infant , Pregnancy , Sialadenitis/immunology , Sudden Infant Death/immunology
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