| 1. |
- Mincheva-Nilsson, Lucia, et al.
(författare)
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gammadelta T cells of human early pregnancy decidua : evidence for cytotoxic potency.
- 2000
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Ingår i: International Immunology. - : Oxford University Press (OUP). - 0953-8178 .- 1460-2377. ; 12:5, s. 585-96
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Tidskriftsartikel (refereegranskat)abstract
- The immune compromise in decidua allows a semiallogeneic fetus to survive without impairing the ability of the maternal immune system to fight infections. Cytotoxic mechanisms are likely to be important in this compromise. Using RT-PCR, immunoflow cytometry and immunoelectron microscopy, the cytotoxic potential of isolated human decidual gammadelta T cells was studied. mRNA for perforin (Pf), granzymes A and B, granulysin and Fas ligand (FasL) was simultaneously expressed in decidual gammadelta T cells. Pf and FasL were not expressed on the cell surface. However, the cells constitutively synthesized Pf and stored it in cytolytic granules. Within the granules Pf mainly resided in the granule core formed by Pf-containing microvesicles. Ultrastructurally, three groups of Pf-containing granules were distinguished. They probably represent different stages of granule maturation in a process where Pf-containing microvesicles first attach to the core cortex and then are translocated across the cortex into the core. Presynthesized FasL was also stored in the core and microvesicles of the cytolytic granules. Upon degranulation by ionomycin/Ca(2+) treatment, FasL was rapidly translocated to the cell surface, demonstrating that its surface expression was not controlled by de novo biosynthesis. Thus decidual gammadelta T cells appear to perform Pf- and FasL-mediated cytotoxicity utilizing a common secretory mechanism based on cytolytic granule exocytosis. The first cytochemical visualization of lipids in the cytolytic granules is provided. These intragranular lipids probably wrap up the core and participate in packaging of the cytotoxic proteins as well as in the killing process. An ultrastructural model of a cytolytic granule is presented.
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| 2. |
- Oberg, ANV, et al.
(författare)
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Detection of occult tumour cells in lymph nodes of colorectal cancer patients using real-time quantitative RT-PCR for CEA and CK20 mRNAS
- 2004
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Ingår i: International Journal of Cancer. - Geneve : Wiley. - 0020-7136 .- 1097-0215. ; 111:1, s. 101-110
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of our study was to develop specific, sensitive, objective assays for early detection of disseminated tumour cells in patients with colorectal cancer (CRC). Carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20) were chosen as markers because they are selectively expressed in epithelial cells with maintained expression in CRC. Real-time quantitative RT-PCR assays with RNA copy standards were constructed. Regional lymph nodes were collected from patients with CRC (n = 5 1) and benign intestinal disease (n = 10). Results were compared to routine histopathology and anti-CEA immunohistochemistry. Lymph node levels of CEA and CK20 mRNA correlated strongly (p < 0.0001, r = 0.8). Lymph nodes from non-CRC patients had <0.01 CEA and <0.001 CK20 mRNA copies/18S rRNA unit. Lymph nodes from 3/6 Dukes' A, 17/26 Dukes' B, 10/10 Dukes' C and 7/9 Dukes' D patients had CEA mRNA levels above cut-off. Corresponding figures for CK20 mRNA were 3/6, 10/26, 9/10 and 5/9, respectively. CEA mRNA levels varied from 0.001 to 100 copies/18S rRNA unit in Dukes' A and B, and 50% of the Dukes' B patients had CEA mRNA levels within the range of Dukes' C patients. Three Dukes' B patients have died from CRC or developed distant metastases. All 3 had high CEA and CK20 mRNA levels. Determination of mRNA was superior to immunohistochemistry in showing CEA expression in lymph nodes. The present qRT-PCR assay for CEA mRNA seems to be a superior tool to identify individuals with disseminated tumour cells. Future extended studies will establish the clinically most relevant cut-off level. (C) 2004 Wiley-Liss, Inc.
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| 3. |
- Baranov, Vladimir, et al.
(författare)
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Carcinoembryonic antigen (CEA) and CEA-related cell adhesion molecule 1 (CEACAM1), apically expressed on human colonic M cells, are potential receptors for microbial adhesion.
- 2004
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Ingår i: Histochemistry and Cell Biology. - : Springer Science and Business Media LLC. - 0948-6143 .- 1432-119X. ; 121:2, s. 83-9
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Tidskriftsartikel (refereegranskat)abstract
- In the human gut mucosa, specialized M cells deliver intact foreign macromolecules and commensal bacteria from the lumen to organized mucosal lymphoid tissues triggering immune responses. M cells are also major sites of adhesion and invasion for enteric pathogens. The molecular features of M cell apical surfaces that promote microbial normal attachment are still largely unknown. We have demonstrated previously that in the human colonic epithelium, carcinoembryonic antigen (CEA) and CEA-related cell adhesion molecule 1 (CEACAM1) are integral components of the apical glycocalyx which participate in epithelial-microbial interactions. In this study, based on the reactivity of specific monoclonal antibodies and on immunoelectron microscopy, we show that M cells of human colonic solitary lymphoid follicles express CEA and CEACAM1 on the apical surface. Recently these highly glycosylated molecules have been characterized as protein receptors for different bacteria. This leads us to propose a role for CEA and CEACAM1 in the adherence of enteric bacteria to the apical membrane of colonic M cells. We also hypothesize that, unlike colonic enterocytes, M cells lack the defense mechanism that eliminates CEA and CEACAM1 upon microbial binding and which is based on vesiculation of microvillus plasma membrane.
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| 4. |
- Baranov, Vladimir, et al.
(författare)
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Lipids are a constitutive component of cytolytic granules.
- 2000
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Ingår i: Histochemistry and Cell Biology. - 0948-6143 .- 1432-119X. ; 114:2, s. 167-71
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Tidskriftsartikel (refereegranskat)abstract
- Cytolytic granules are specific organelles of activated cytotoxic lymphocytes mediating storage and regulated excretion of lytic molecules for killing of target cells. A variety of the other granule components may also participate in granule-mediated cytotoxicity. In this study, the subcellular localization of lipids in the granules of human decidual CD56+ natural killer-like cells was determined by staining with malachite green aldehyde and imidazole-buffered osmium tetroxide. Lipids were shown, for the first time, to be a constitutive component of cytolytic granules. Lipids formed an additional structural microdomain, located between the granule-limiting membrane and the granule core. Images of the granules on serial sections suggested that intragranular lipids wrap the core. We speculate that granule lipids participate in packing of lytic molecules inside the granules, in autocrine signaling ending granule secretion, and in the killing process.
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| 5. |
- Bas, Anna, 1973-
(författare)
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Extrathymic T cell receptor gene rearrangement in human alimentary tract
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- T lymphocytes regulate the initiation, duration, and magnitude of adaptive immune responses and function as effector cells in cell mediated immunity. To become immunologically competent they must generate functional antigen receptors. This process takes place in the thymus and requires somatic recombination of T cell receptor (TCR) genes. It is mediated by the endonucleases recombination activating gene-1 (RAG1) and RAG2. Although the thymus regresses at puberty, T cells are present throughout life implying that other tissues must provide the proper milieu for T cell development. This thesis describes extrathymic T cell maturation in man. RAG1, RAG2, and the preTα-chain (pTα), which is exclusively utilized in developing T cells, were used as markers for TCR gene rearrangement. Two new exons (1A and 1B) encoding sequences in the 5’ untranslated region (5’UTR) of mRNA were discovered in the human RAG1 gene. The previously described 5’UTR exon (renamed 1C) was located between the new exons and exon 2, the latter containing the entire coding sequence. We found that small intestinal lymphocytes of the T cell lineage expressed the new exons in three different splice forms. RAG1 mRNA containing the 1C exon was not expressed in small intestinal lymphocytes. In contrast, splice forms containing the 1A exon were not expressed in thymocytes. RAG1 and pTα mRNA expressing lymphocytes were seen both within the epithelium and in lamina propria. Thymocyte-like CD2+CD7+CD3-, CD4+CD8+, CD1a+, and IL7-R+ lymphocytes were identified in the small intestinal mucosa. CD2+CD7+CD3- cells had the highest expression levels of mRNA for RAG1 and pTα, suggesting that the small intestinal mucosa is indeed a site for T cell maturation. Small intestinal T lymphocytes were also shown to kill via the Fas/FasL pathway in a TCR/CD3 independent manner and via the perforin/granzyme pathway in a TCR/CD3 dependent manner. The Fas/FasL-mediated cytotoxicity may reflect an ongoing selection process of extrathymically maturated T cells.The nasopharyngeal tonsil is the major inductive site for immune reactions against inhaled antigens. Previous demonstration of RAG1 expression in tonsillar B cells was interpreted as antigen driven receptor revision. The present study confirms the expression of RAG1 in B cells. We also found that RAG1, RAG2, and pTa mRNAs were expressed in lymphocytes of the T cell lineage. A small population of cells with the immature phenotype CD2+CD7+CD3- was demonstrated. This population had the highest expression levels of mRNA for RAG1, RAG2, pTα and terminal deoxynucleotidyl transferase. All four splice-forms of RAG1 mRNA were expressed. RAG1 and pTα mRNA expressing cells were mainly located in the proximity of the surface epithelium and in the outer rim of the follicles. These results suggest that the nasopharyngeal tonsil is a site where extrathymic T cell development and antigen driven TCR revision are occurring in parallel.Celiac disease (CD) is a small intestinal enteropathy characterized by permanent intolerance to gluten. Gluten reactive intestinal T cells are central in the pathogenesis and CD can be regarded as a failure to maintain tolerance to this food antigen. Expression of the RAG1 1A/2 splice form was significantly decreased in small intestinal T cell subsets of CD patients suggesting that impaired TCR gene rearrangement could contribute to failure of maintain tolerance in CD.Together, these findings show that both small intestinal and nasopharyngeal tonsillar lymphocytes of T cell lineage have the molecular machinery for antigen receptor rearrangement and that thymocyte-like lymphocytes are present in both tissues. Thus these organs are likely sites of T lymphocyte ontogeny as well as for secondary T cell receptor rearrangement in man.
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| 6. |
- Bas, Anna, et al.
(författare)
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Extrathymic TCR gene rearrangement in human small intestine : identification of new splice forms of recombination activating gene-1 mRNA with selective tissue expression.
- 2003
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Ingår i: Journal of Immunology. - 0022-1767 .- 1550-6606. ; 171:7, s. 3359-71
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Tidskriftsartikel (refereegranskat)abstract
- Two new 5'-untranslated region (5'UTR) exons were identified in the human gene for the lymphocyte-specific endonuclease recombination activating gene-1 (RAG1) required for the somatic recombination yielding functional Ag receptors. These 5'UTR exons were used in three different splice forms by jejunal lymphocytes of the T cell lineage. RAG1 mRNA containing the previously described 5'UTR exon was not expressed in these cells. Conversely, one of the new 5'UTR exons was not expressed in thymus. The new RAG1 mRNA splice forms were all expressed in immature T cells (CD2(+)CD7(+)CD3(-)). This cell population also expressed high levels of mRNA for the pre-T alpha-chain. In situ hybridization demonstrated jejunal cells expressing the new splice forms of RAG1 mRNA, both intraepithelially and in lamina propria. Pre-T alpha-chain mRNA-expressing cells were detected at the same sites. These results strongly suggest ongoing TCR gene rearrangement in human small intestinal mucosa, yielding T cells specially adapted for this environment. This seems to be achieved by two parallel processes, extrathymic T cell development and peripheral Ag-driven TCR editing.
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| 7. |
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| 8. |
- Bas, Anna, et al.
(författare)
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Utility of the housekeeping genes 18S rRNA, β-actin, and glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) for normalisation in real-time quantitative RT-PCR analysis of gene expression in human T lymphocytes
- 2004
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Ingår i: Scandinavian Journal of Immunology. - : John Wiley & Sons. - 0300-9475 .- 1365-3083. ; 59:6, s. 566-573
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Tidskriftsartikel (refereegranskat)abstract
- The accuracy of 18S rRNA, β-actin mRNA and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA as indicators of cell number when used for normalization in gene expression analysis of T lymphocytes at different activation stages was investigated. Quantitative real-time reverse transcriptase-polymerase chain reaction was used to determine the expression level of 18S rRNA, β-actin mRNA, GAPDH mRNA and mRNA for six cytokines in carefully counted samples of resting human peripheral blood mononuclear cells (PBMCs), intestinal lymphocytes and PBMCs subjected to polyclonal T-cell activation. The 18S rRNA level in activated and resting PBMCs and intestinal lymphocytes was essentially the same, while the levels of β-actin and GAPDH mRNAs fluctuated markedly upon activation. When isolated γδTCR+, CD4+ and CD8+ subpopulations were studied, 18S rRNA levels remained unchanged after 21 h of activation but increased slightly after 96 h. In contrast, there was a 30–70-fold increase of GAPDH mRNA/cell in these cell populations upon activation. Cytokine analysis revealed that only normalization to 18S rRNA gave a result that satisfactorily reflected their mRNA expression levels per cell. In conclusion, 18S rRNA was the most stable housekeeping gene and hence superior for normalization in comparative analyses of mRNA expression levels in human T lymphocytes.
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| 9. |
- Bjerner, J, et al.
(författare)
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Protein epitopes in carcinoembryonic antigen. Report of the ISOBM TD8 workshop.
- 2002
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Ingår i: Tumor Biology. - : Springer Science and Business Media LLC. - 1010-4283 .- 1423-0380. ; 23:4, s. 249-62
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Tidskriftsartikel (refereegranskat)abstract
- To characterize antigenic sites in carcinoembryonic antigen (CEA) further and to investigate whether there are differences between colon tumor CEA and meconium CEA (NCA-2) that can be detected by anti-CEA monoclonal antibodies (MAb), 19 new anti-CEA MAb were analyzed with respect to specificity, epitope reactivity and affinity. Their reactivities were compared with 10 anti-CEA MAb with known CEA-domain binding specificity that have previously been classified into five nonoverlapping epitope groups, GOLD 1-5. Cross-inhibition assays with antigen-coated microtiter plates and immunoradiometric assays were performed in almost all combinations of MAbs, using conventionally purified CEA (domain structure: N-A1B1-A2B2-A3B3-C) from liver metastasis of colorectal carcinomas, recombinant CEA, meconium CEA (NCA-2), truncated forms of CEA and NCA (CEACAM6) as the antigens. The affinity of the MAbs for CEA was also determined. The new MAbs were generally of high affinity and suitable for immunoassays. Three new MAbs were assigned to GOLD epitope group 5 (N-domain binding), 3 MAbs to group 4 (A1B1 domain), 1 to group 3 (A3B3 domain), 3 to group 2 (A2B2 domain) and 3 to group 1 (also the A3B3 domain). Three MAbs formed a separate group related to group 4, they were classified as GOLD 4' (A1B1 domain binding). The remaining 3 MAbs appear to represent new subspecificities with some relationship to GOLD groups 1, 2 or 4, respectively. Five MAbs, all belonging to epitope group 1 and 3, reacted strongly with tumor CEA but only weakly or not at all with meconium CEA, demonstrating that the two products of the CEA gene differ from each other, probably due to different posttranslational modifications.
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| 10. |
- Fahlgren, Anna, 1972-
(författare)
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Defence capabilities of human intestinal epithelial cells
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The epithelial cells lining the intestinal mucosa separate the underlying tissue from components of the intestinal lumen. Innate immunity mediated by intestinal epithelial cells (IECs) provides rapid protective functions against microorganisms. Innate immunity also participates in orchestrating adaptive immunity. Key components in innate defence are defensins.To study the production of defensins and how it is affected by intestinal inflammation IECs were isolated from the small and large intestines of patients suffering from ulcerative colitis (UC), Crohn´s disease (MbC), celiac disease (CD), and from controls, and analyzed by quantitative RT-PCR (qRT-PCR) and immunoflow cytometry. Defensin expressing cells were also studied by in situ hybridization and immunohistochemistry.Normally, only small intestinal Paneth cells express human α-defensin 5 (HD-5) and HD-6. In UC colon IECs, HD-5, HD-6, and lysozyme mRNAs were expressed at high levels. In Crohn´s colitis colon the levels of HD-5 and lysozyme mRNAs were also increased although not to the same extent as in UC. No increase was detected in MbC with ileal localization. Metaplastic Paneth cell differentiation in UC colon was primarily responsible for the expression of the antimicrobial components. Human β-defensin 1 (hBD-1) mRNA was more abundant in large than in small intestine of controls, and remained unchanged in UC and MbC. hBD-2 mRNA was barely detectable in normal intestine and was induced in UC IECs but not in MbC IECs. mRNAs for the recently discovered hBD-3 and hBD-4, were detected in IECs from both small and large intestine. Both hBD-3 and hBD-4 mRNA were significantly increased in IECs of UC patients but not of MbC patients. Bacteria and IL-1β induced hBD-2 but not hBD-1 mRNA in colon carcinoma cell lines. IFN-γ, but not TNF-α or IL-1β, augmented hBD-3 expression in these cells, while none of the agents induced hBD-4. High antimicrobial activity of IECs in UC may be a consequence of changes in the epithelial lining, which permit the adherence of microorganisms.Unexpectedly, in situ hybridization revealed expression of hBD-3 and hBD-4 mRNAs by numerous lamina propria cells in colonic tissue from UC patients. These cells were identified as plasma cells (CD138+). hBD-3 and hBD-4 mRNAs were also demonstrated in the plasmacytoma cell line U266. This is the first demonstration of defensins in plasma cells.The four prominent constituents of the intestinal glycocalyx, carcinoembryonic antigen (CEA), CEA cell adhesion molecule 1 (CEACAM1), CEACAM6 and CEACAM7 all seem to play a critical role in innate defence of the intestinal mucosa by trapping and expelling microorganisms at the epithelial surface. The inducibility of these molecules in colonic epithelial cell lines was analyzed by qRT-PCR, immunoflow cytometry, and immunoelectron microscopy. IFN-g but not bacteria, LPS, TNF-α, or IL-1β modified the expression of CEA, CEACAM1 and CEACAM6. None of these agents modified CEACAM7 expression. IFN-γ was shown to have two effects: a direct effect on CEACAM1 transcription, and promotion of cell differentiation resulting in increased CEA and CEACAM6 and decreased CEACAM7 expression.Scanning electron microscopy of jejunal biopsies from children with CD revealed the presence of rod shaped bacteria in ~40% of patients with active CD, but only in 2% of controls. 19% of treated CD patients still had adhering bacteria. Presence of bacteria is not due to lack of antimicrobial factors. In fact, HD-5, HD-6, and lysozyme mRNA levels were significantly increased in IECs of patients with active CD. hBD-1 and hBD-2 were unchanged. Lack of induction of hBD-2 may reflect disturbed signalling in IECs of CD patients. Analysis of CEA and CEACAM1 mRNA/protein expression showed no differences between CD patients and controls. Analysis of the mucins MUC2 and MUC3 revealed significantly increased MUC2 levels in active disease and unchanged MUC3. Immunohistochemistry demonstrated goblet cell metaplasia as well as staining of the apical portion of absorptive cells. Glycosylation status of proteins was studied by lectin histochemistry. Goblet cells in the mucosa of CD patients were stained by the lectin UEAI. This was not seen in controls. The lectin PNA stained the glycocalyx of controls but not that of CD patients. Thus, unique carbohydrate structures of the glycocalyx/mucous layer are likely discriminating features of CD patients and may allow bacterial binding.We conclude that the intestinal epithelium is heavily involved in the innate defence of the mucosa and that its reactive pattern is affected by intestinal inflammation.Keywords: human intestinal mucosa; epithelial cells; innate immunity; defensin; ulcerative colitis; Crohn´s disease; celiac disease; glycoαcalyx; mucin
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