bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soluble isoforms of CEACAM1 containing the A2 domain: increased serum levels in patients with obstructive jaundice and differences in 3‐fucosyl‐N‐acetyl‐lactosamine moiety
Authors: Dráberová L. , Černá H. , Brodská H. , Boubelík M. , Watt S. M. , Stanners C. P. , Dráber P. 
Published: March 2003

SummaryCEACAM1 (biliary glycoprotein or CD66a) is a member of the carcinoembryonic antigen (CEA) subgroup of the CEA family. Eleven RNA isoforms derived from the splicing of a single CEACAM1 gene have been described. Some of the CEACAM1 isoforms have been recognized by the CD66 antibodies in T and B lymphocytes, natural killer cells, granulocytes and epithelial cells in several human tissues. Although it is also present in soluble form in bile and serum, and elevated levels have been found in the serum of patients with liver diseases, it is not known which isoforms are primarily involved. In order to learn more about the distribution and properties of particular CEACAM1 isoforms, we have prepared a monoclonal antibody specific for the A2 domain of CEACAM1, designated TEC‐11. This antibody does not cross‐react with other members of the CEA family. Immunoblotting analysis revealed that the TEC‐11 epitope was present in all cell types expressing CEACAM1 containing the A2 domain [CEACAM1(A2)], including granulocytes (160 000 MW isoform) and sperm cells (140 000 MW isoform). A 115 000 MW isoform of CEACAM1(A2) was present in human serum, bile, saliva and seminal fluid. Human bile, saliva and seminal fluid also contained the 160 000 MW CEACAM1(A2) isoform. Significantly higher serum levels of the 115 000 MW CEACAM1(A2) isoform were detected in patients with obstructive jaundice. The 160 000 MW isoform of CEACAM1(A2) in bile, but not a 115 000 MW isoform in serum and bile, carried the 3‐fucosyl‐N‐acetyl‐lactosamine moiety. The combined data indicate that various isoforms of CEACAM1(A2) are present in different body fluids where they could take part in different CEACAM1‐mediated functions.
The C5a receptor is expressed in normal renal proximal tubular but not in normal pulmonary or hepatic epithelial cells
Authors: Fayyazi A. , Scheel O. , Werfel T. , Schweyer S. , Oppermann M. , Götze O. , Radzun H. J. , Zwirner J. 
Published: March 2003

SummaryC5a, a 74 amino acid peptide cleaved from the complement protein C5, is an extremely potent anaphylatoxin. Expression of the receptor for the anaphylatoxin C5a (C5aR) has been thought to be restricted to cells of myeloid origin. However, recent evidence suggests that the C5aR is also expressed in hepatocytes as well as in pulmonary epithelial, endothelial and smooth muscle cells. In the present study, we investigated the tissue distribution of C5aR by immunohistochemistry in normal human lung, liver, intestine and kidney using well‐defined monoclonal antibodies (mAbs) directed against the extracellular N‐terminus of the receptor. In all tissues examined, macrophages displayed an abundant expression of C5aR protein. However, in the normal human lung, C5aR expression was not detectable in bronchial and alveolar epithelial cells or in vascular smooth muscle or endothelial cells. In the normal human liver, no C5aR protein was detected in hepatocytes, whereas Kupffer cells strongly expressed the C5aR. In normal human kidney, the C5aR was detectable only in proximal tubular cells. C5aR gene transcription in Kupffer cells and proximal tubular cells was confirmed by in situ hybridization. Thus, our results point to an as yet unknown role of the C5aR in normal renal physiology. In the normal lung and liver, however, previous evidence for the ubiquitous expression of C5aR in epithelial, endothelial and smooth muscle cells in situ should be re‐evaluated.
Vγ1+γδ T cells play protective roles at an early phase of murine cytomegalovirus infection through production of interferon‐γ
Authors: Ninomiya T. , Takimoto H. , Matsuzaki G. , Hamano S. , Yoshida H. , Yoshikai Y. , Kimura G. , Nomoto K. 
Published: March 2003

SummaryCytomegalovirus (CMV) causes severe opportunistic infection in immunocompromised hosts. The importance of conventional αβ T cells in protection against CMV infection has been well documented. However, the role of the second T‐cell population (which express the γδ T‐cell receptor) in CMV infection is not known. In the present study, we analysed the function and protective role of γδ T cells in a murine cytomegalovirus (MCMV) infection model. After intraperitoneal infection with MCMV, the number of γδ T cells increased in the liver and peritoneal cavity from day 3, and reached a peak on day 5. The γδ T cells showed an activated T‐cell phenotype and predominantly expressed Vγ1, which is known to be expressed by heat‐shock protein 65 (hsp 65)‐specific γδ T cells. Analysis of cytokine expression demonstrated that the MCMV‐induced γδ T cells expressed interferon‐γ (IFN‐γ) and tumour necrosis factor‐α (TNF‐α) but not interleukin‐4 (IL‐4), implying their participation in the cell‐mediated immune response against MCMV. Depletion of γδ T cells by anti‐T‐cell receptor (TCR) γδ monoclonal antibody (mAb) treatment resulted in significant increase of virus titre and decrease of IFN‐γ in the liver on day 3 after MCMV infection, which further supports the importance of γδ T cells in early protection against infection. Finally, the MCMV‐induced γδ T cells produced IFN‐γin vitro in response to hsp 65. Our results suggest that γδ T cells participate in early protection against MCMV infection through recognition of hsp 65 and production of IFN‐γ.
T‐cell apoptosis and differential human leucocyte antigen class II expression in human thymus
Authors: Douek D. C. , Altmann D. M. 
Published: March 2003

SummaryRelatively little is known of the details of human leucocyte antigen (HLA) expression and thymocyte selection in human thymus. In both humans and mice major histocompatibility complex (MHC) molecules have been described which show a highly restricted thymic expression. Such patterns may offer clues about cellular interactions in thymic selection because transgenic mice with MHC expression targeted to specific thymic sites show altered T‐cell receptor (TCR) repertoire selection. We have analysed human thymic HLA class II expression, relating the expression pattern to sites of thymocyte apoptosis. While HLA‐DQ is poorly expressed by most peripheral antigen‐presenting cells (APC), thymus stains strongly for HLA‐DQ as well as for HLA‐DR. HLA‐DM is abundant in medulla but weakly expressed by cortical cells. Class II expression in Hassall’s corpuscles (HC) is unusual in several respects: we have previously shown them to be encircled by HLA‐DO+ epithelial cells and here further demonstrate that HC are negative for HLA‐DR and HLA‐DP, but often positive for HLA‐DQ and HLA‐DM. Transcriptional control of HLA class II products at this site is thus unlike cells that have previously been studied. Apoptotic thymocytes are restricted to the cortex and the corticomedullary junction. However, a minority of apoptotic cells are visible in the medulla, these being found in the HLA‐DQ positive HC. The apoptotic thymocytes in HC can be CD4+ single positive (SP), CD8+ SP or CD4+CD8+ double‐positive (DP). This study thus shows that the HC within human thymic medulla are noteworthy both for their unusual hierarchy of HLA class II expression and because they are the only medullary site of thymocyte apoptosis. We propose that HC are a site at which mature thymocytes receive activation/tolerization signals from peptides reprocessed from apoptotic cells. The differential HLA transcriptional control at this site may indicate that specific T‐cell subpopulations are affected.
Immunostimulatory bacterial DNA sequences activate dendritic cells and promote priming and differentiation of CD8+ T cells
Authors: Tascon R. E. , Ragno S. , Lowrie D. B. , Colston M. J. 
Published: March 2003

SummaryCD8+ T lymphocytes producing high levels of interferon‐γ (IFN‐γ) and expressing antigen specific cytotoxic activity are effectively induced after plasmid DNA vaccination and mediate protection against several intracellular micro‐organisms. Recent evidence suggests that the priming of CD8+ T‐cell responses following DNA injection involves antigen presentation mediated by dendritic cells. Here, we show that bacterial DNA and synthetic oligonucleotides containing dinucleotide (CpG) motifs activate cytokine expression in dendritic cells and modulate in vivo CD8+ T‐cell priming and differentiation.
Interaction of merosin (laminin 2) with very late activation antigen‐6 is necessary for the survival of CD4+ CD8+ immature thymocytes
Authors: Iwao M. , Fukada S. , Harada T. , Tsujikawa K. , Yagita H. , Hiramine C. , Miyagoe Y. , Takeda S. , Yamamoto H. 
Published: March 2003

SummaryThe laminin α2‐chain is a component of merosin, a member of the laminin family molecules, which is mainly expressed in the basement membranes of striated muscle. It is known that laminin α2 gene (lama2) null mutant mice (dy3k/dy3k) exhibit congenital muscular dystrophy (CMD). Because the laminin α2‐chain is also expressed in the thymus, the role of merosin in the thymus was examined. In association with the onset of muscular dystrophy, CD4+ CD8+ double‐positive (DP) thymocytes disappear by apoptotic cell death, while CD4+ CD8– or CD4– CD8+ thymocytes remain. In order to study the mechanisms leading to the selective death of DP cells in the absence of merosin, the role of the interaction between very late activation antigen‐6 (VLA‐6), a candidate merosin ligand in the thymus, and merosin was examined. The in vitro survival of thymocytes from normal mice was maintained by the addition of either anti‐VLA‐6 monoclonal antibodies (mAbs) or merosin. Furthermore, when the normal thymocytes were cultured on thymic epithelial cell lines, viable DP cell recoveries on wild‐type epithelial cells were better than on cells from null mutant mice. The results suggest that DP cells are more sensitive to an uncharacterized apoptotic death signal, and that survival is supported by the interaction between VLA‐6 and merosin.
Up‐regulation of β‐chemokines and down‐modulation of CCR5 co‐receptors inhibit simian immunodeficiency virus transmission in non‐human primates
Authors: Lehner T. , Wang Y. , Cranage M. , Tao L. , Mitchell E. , Bravery C. , Doyle C. , Pratt K. , Hall G. , Dennis M. , Villinger L. , Bergmeier L. 
Published: March 2003

SummaryA non‐cognate mechanism of protection against human immunodeficiency virus‐1 (HIV‐1) infection involves up‐regulation of β‐chemokines, which bind and may down‐modulate the CCR5 co‐receptors, thereby preventing transmission of M‐tropic HIV‐1. The objective of this investigation was to evaluate this mechanism in vivo in non‐human primates. Rhesus macaques were immunized by a modified targeted lymph nodes (TLN) route with recombinant simian immunodeficiency virus (SIV) glycoprotein 120 (gp120) and p27 in alum, and adsorbed recombinant granulocyte–macrophage colony‐stimulating factor (GM‐CSF) with either interleukin (IL)‐2 or IL‐4. Immunization induced significant increases in the concentrations of CD8 cell‐derived suppressor factor (CD8‐SF), regulated on activation normal T cells expressed and secreted (RANTES), macrophage inflammatory protein (MIP)‐1α and MIP‐1β, and down‐modulation of the proportion of cells expressing CCR5 (r = 0·737, P < 0·05). The macaques were then challenged with SIVmac 220 by the rectal mucosal route. The plasma SIVmac RNA showed a significant inverse correlation with the CD8‐SF or the concentration of the three β‐chemokines (r = 0·831 and 0·824, P < 0·01), but a positive correlation between the proportion of CCR5+ cells and SIVmac RNA (r = 0·613, P = 0·05). These results demonstrate for the first time in vivo that immunization up‐regulates β‐chemokines, which may down‐modulate CCR5 co‐receptors, and both functions are significantly correlated with the viral load. Hence, the non‐cognate β‐chemokine–CCR5 mechanism should be considered as complementary to specific immunity in vaccination against HIV.
Fas–FasL interaction modulates nitric oxide production in Trypanosoma cruzi‐infected mice
Authors: Martins Gislâine A. , Petkova Stefka B. , Machado Fabiana S. , Kitsis Richard N. , Weiss Louis M. , Wittner Murray , Tanowitz Herbert B. , Silva João S. 
Published: March 2003

SummaryDuring acute Trypanosoma cruzi infection in mice, many leucocytes undergo apoptosis. Although apoptosis has been ascribed to increased levels of nitric oxide (NO) and Fas–FasL interaction, the importance of this phenomenon in modulating the host response against T. cruzi is unknown. Herein, the role of NO‐ and Fas–FasL‐induced apoptosis in modulating the immune response to T. cruzi was evaluated using mice deficient in Fas expression (MRL/MpJ‐Fas lpr) and inducible nitric oxide synthase (iNOS) knockout mice (iNOS–/–). The results showed that besides decreasing apoptosis induction after infection, impairment of the Fas–FasL interaction resulted in decreased NO production, as a consequence of enhanced T helper 2 (Th2) cytokine production. Differently, blockage of NO‐induced apoptosis resulted in uncontrolled cytokine production, rather than a biased Th2 cytokine pattern. Together, these results suggested that Fas and FasL‐induced apoptosis could be implied in modulation of the immune response against T. cruzi by interfering with cytokine and NO production during the acute phase of the infection.
Studies on transcriptional regulation of the mucosal T‐cell integrin αEβ7 (CD103)
Authors: Robinson Paul W. , Green Sally J. , Carter Christine , Coadwell John , Kilshaw Peter J. 
Published: March 2003

SummaryIntegrin αEβ7 is expressed almost exclusively by mucosal T cells and mucosal dendritic antigen‐presenting cells (APCs) and is thought to be induced locally by transforming growth factor‐β (TGF‐β). In mice, mRNA for the αE subunit was found to be abundant in mucosal T cells but absent from other tissues. Exposure of a T‐cell line to TGF‐β strongly up‐regulated αE mRNA levels within 30 min, and nuclear run‐on experiments established that regulation occurred at the level of transcription. The organization of the human αE gene and a very closely linked novel gene, ELG, was determined. The αE promoter was tested in T cells and fibroblasts and functioned equally well in both cell types and did not confer TGF‐β responsiveness. Regions of the promoter providing enhancer activity and phorbol 12‐myristate 13‐acetate (PMA) responsiveness were identified by deletion studies. DNAse 1 hypersensitivity analysis of 36 kb of the αE gene revealed one hypersensitive site, found only in αE+ cells, located near the transcription start points. These results show that, unlike the situation with other integrins, lineage specificity and cytokine responsiveness of αE transcription are not conferred by the proximal promoter. Specificity may depend on distant control elements that have not yet been identified.
Evidence of the extrathymic development of tyrosinase‐related protein‐2‐recognizing CD8+ T cells with low avidity
Authors: Harada, Mamoru , Yamada Hisakata , Tatsugami Katsunori , Nomoto Kikuo 
Published: March 2003

SummaryThe majority of the human tumour‐associated antigens characterized to date are derived from non–mutated self‐proteins. However, nothing is known about the development of autoreactive and tumour‐associated antigen‐recognizing T cells. Tyrosinase‐related protein (TRP)‐2 is a non‐mutated melanocyte differentiation antigen and TRP‐2‐recognizing CD8+ T cells are known to show responses to melanoma both in humans and mice. In addition, TRP‐2‐reactive T cells with low avidity have been suggested to be readily induced from the spleen cells of naïve mice. On the other hand, recent reports suggest that self antigen‐reactive CD8+ T cells can be positively selected in the periphery. In this study, we tested the possibility that TRP‐2‐reactive CD8+ T cells in naïve mice could develop via the extrathymic pathway. As a consequence, TRP‐2‐reactive CD8+ T cell precursors in naïve C57BL/6 mice were suggested to express both interleukin‐2 (IL‐2) receptor β chain (IL‐2Rβ) and CD44 molecules, in a manner similar to that of extrathymically developed T cells. Furthermore, IL‐2Rβ+ CD44+ CD8+ T cells were detected in the adult thymectomized and bone marrow‐reconstituted mice, and functional TRP‐2‐reactive T cells were generated from their spleen cells. Overall, these results suggest that low avidity CD8+ T cells recognizing TRP‐2 can be developed extrathymically.
Murine gammaherpesvirus‐68‐induced interleukin‐10 increases viral burden, but limits virus‐induced splenomegaly and leukocytosis
Authors: Peacock James W. , Bost Kenneth L. 
Published: March 2003

SummaryBased on its genomic sequence and its pathogenesis, murine gammaherpesvirus‐68 (γHV‐68) has been established as a tractable model for the study of viral infections caused by the human gammaherpesviruses, Epstein–Barr virus or human herpesvirus‐8. Despite significant advances, the mechanisms responsible for γHV‐68‐induced alterations in the protective host response, and the accompanying virus‐induced leukocytosis, are not clear. In the present study, we questioned whether viral infection resulted in endogenous interleukin‐10 (IL‐10) production that might alter the host response. Infection of C57BL/6 mice resulted in increased IL‐10 expression, demonstrating that γHV‐68 could induce endogenous production of this cytokine. Infected C57BL/6 mice demonstrated the characteristic splenomegaly associated with this viral infection, however, we were surprised to discover that the splenomegaly was greater in syngeneic mice genetically deficient in IL‐10 (IL‐10−/−). These results strongly suggested that endogenously produced IL‐10 might serve to limit leukocytosis in wild‐type mice. Quantification of viral burden demonstrated a significant elevation in C57BL/6 versus IL‐10−/− mice, with increases in virus being observed in both the macrophage and B‐lymphocyte populations. The decreased viral load in syngeneic IL‐10−/− mice correlated with an increased expression of endogenous IL‐12, suggesting a mechanism of protection that was IL‐12 dependent. Taken together, these studies demonstrate a surprising dichotomy for endogenous IL‐10 production during γHV‐68 infection. While the lack of IL‐10 results in increased IL‐12 expression and a lower viral burden, IL‐10−/− mice also experience an increased leukocytosis.
Diacylglycerol kinase α activity promotes survival of CD4+ 8+ double positive cells during thymocyte development
Authors: Outram Susan V. , Crompton Tessa , Merida Isabel , Varas Alberto , Martinez‐A Carlos 
Published: March 2003

SummaryThe diacylglycerol kinases (DGK) form a family of isoenzymes that catalyse the conversion of diacylglycerol (DAG) to phosphatidic acid (PA), both powerful second messengers in the cell. DGKα is expressed in brain, peripheral T cells and thymocytes and has been shown to translocate to the nuclear matrix upon T‐cell receptor (TCR) engagement. Here, we show that high level expression of DGKα is induced following a signal transmitted through the pre‐TCR and the protein tyrosine kinase, lck. Activity of DGKα contributes to survival in CD4+ 8+ (DP) thymocytes as pharmacological inhibition of DGK activity results in death of this cell population both in cell suspension and thymic explants. DGKα promotes survival in these thymocytes through a Bcl‐regulated pathway. A consequence of inhibition of DGKα is the specific down‐regulation of Bcl‐xl, whereas in transgenic mice that over‐express Bcl‐2, death induced by the inhibitor is partially blocked. Thus we report a novel activity of DGKα in survival of thymocytes immediately after entry into the DP stage in development.
Age‐related telomere length dynamics in peripheral blood mononuclear cells of healthy cynomolgus monkeys measured by Flow FISH
Authors: Lee Won‐Woo , Nam Ki‐Hoan , Terao Keiji , Yoshikawa Yasuhiro 
Published: March 2003

SummaryTelomere length is a good biomarker to study the cellular senescence as well as aging of an organism, because it regulates the replicative capacity of vertebrate somatic cells. To demonstrate age‐related telomere length dynamics in the peripheral blood mononuclear cells (PBMC) of the cynomolgus monkey, we introduced a novel method of measuring telomere length by fluorescence in situ hybridization with a Peptide Nucleic Acid (PNA) labelled probe and flow cytometry (Flow FISH). A highly significant correlation was observed between the intensity of telomere‐specific fluorescence by Flow FISH and telomere length by Southern blot analysis (R = 0·923, n = 22). The intensity of telomere fluorescence in PBMC significantly decreased with age in 55 monkeys aged from 0 to 34 years and this decrease corresponded to the loss of 62·7 base pairs per year (R = − 0·52, P < 0·00004). We also analysed the expression of naive cell‐associated markers, CD28, CD62L and CD45RA/CD62L in T lymphocytes of 47 cynomolgus monkeys. An age‐related increase in the CD28− subset was observed in CD8+ T lymphocytes in monkeys less than 11 years old and in CD4+ T lymphocytes in monkeys over 23 years old, respectively. The percentage of CD62L+ subsets was significantly decreased with age in both CD4+ (R = − 0·55) and CD8+ T lymphocytes (R = − 0·73). From the comparison of telomere length among PBMC, CD62L+ and CD62L− T lymphocytes, it was clearly evident that loss of naive subsets results in the shortening of telomere length in vivo. These results show that this method can be applicable to studying the turnover and precursor‐progeny of PBMC in cynomolgus monkeys as an animal model of aging.
Characterization of human CD25+ CD4+ T cells in thymus, cord and adult blood
Authors: Wing Kajsa , Ekmark Ann , Karlsson Helen , Rudin Anna , Suri‐Payer Elisabeth 
Published: March 2003

SummaryCD4+ CD25+ regulatory T cells prevent organ‐specific autoimmune diseases in various animal models. We analysed human lymphoid tissues to identify similar CD25+ regulatory T cells. Adult peripheral blood contained two populations of CD4+ T cells that expressed CD25 at different densities. The larger population (≈ 40%) expressed intermediate levels of CD25 (CD25+) and displayed a memory T‐cell phenotype (CD45RA−/RO+, CD45RBlow, CD95+, CD62Llow, CD38low). The smaller population of cells (≈ 2%) expressed very high levels of CD25 (CD25++). In addition to the activation/memory T‐cell antigens mentioned above they also expressed intracellular CD152 (CTLA‐4) as well as enhanced levels of cell‐surface CD122, similar to the murine CD4+ CD25+ regulatory counterpart. To exclude that the CD25++ cells had not been recently primed by external antigen we analysed cord blood and thymus. CD25++, CD152+ and CD122++ cells were present in paediatric thymus (10% of CD4+ CD8− thymocytes) expressing signs of recent selection (CD69+) and in cord blood (5% of CD4+ cells) where they showed a naive phenotype. In addition, cord blood contained a small population of CD25+ cells (≈ 2% of CD4 T cells) that were CD152− and CD122low and displayed signs of activation. Together with published data that CD25+ CD25++ cells from the thymus and peripheral blood are regulatory, our results suggest that regulatory CD25+ T cells leave the thymus in a naïve state and become activated in the periphery.