bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intercellular communication in the immune system: differential expression of connexin40 and 43, and perturbation of gap junction channel functions in peripheral blood and tonsil human lymphocyte subpopulations
Authors: Oviedo‐orta E. , Hoy T. , Evans W. H. 
Published: March 2003

SummaryThe distribution and function of connexins (integral membrane proteins assembled into gap junction intercellular communication channels) were studied in human lymphocyte subpopulations. The expression of mRNA encoding connexins in peripheral blood and tonsil‐derived T, B and natural killer (NK) lymphocytes was examined. Connexin43 (Cx43) mRNA was expressed in peripheral blood and tonsil lymphocytes, but Cx40 mRNA expression was confined to tonsil‐derived T and B lymphocytes; Cx26, Cx32, Cx37 and Cx45 were not detected by reverse transcription–polymerase chain reaction (RT–PCR). Western blot analysis also demonstrated the presence of Cx40 and Cx43 proteins in T and B lymphocytes in a manner coincidental to the mRNA detection. Stimulation in vitro of T and B lymphocytes with phytohaemagglutinin (PHA) and lipopolysaccharide (LPS), respectively, increased Cx40 and Cx43 protein expression. Flow cytometric analysis, using antibodies to extracellular loop amino acid sequences of connexins, confirmed the surface expression of connexins in all lymphocyte subpopulations. Assembly of connexins into gap junctions providing direct intercellular channels linking attached lymphocytes was demonstrated by using a dye transfer technique. The exchange of dye between lymphocytes was inhibited by a connexin extracellular loop mimetic peptide and α‐glycyrrhetinic acid, two reagents that restrict intercellular communication across gap junctions. Dye coupling occurred between homologous and heterologous co‐cultures of T and B lymphocytes, and was not influenced by their stimulation with PHA and LPS. The connexin mimetic peptide caused a significant decrease in the in vitro synthesis of immunoglobulin M (IgM) by T‐ and B‐lymphocyte co‐cultured populations in the presence or absence of stimulation by PHA. The results identify connexins as important cell surface components that modulate immune processes.
Functional dissection of the cytoplasmic subregions of the interleukin‐5 receptor α chain in growth and immunoglobulin G1 switch recombination of B cells
Authors: Moon B.‐G. , Yoshida T. , Shiiba M. , Nakao K. , Katsuki M. , Takaki S. , Takatsu K. 
Published: March 2003

SummaryThe interleukin‐5 receptor α chain (IL‐5Rα) is known to regulate the development and function of B cells and eosinophils. Although the functions of IL‐5Rα cytoplasmic domain subregions have been studied extensively using cultured cell lines, this approach has limitations when studying the functions of distinct primary B‐cell subpopulations and their responsiveness to IL‐5. In the present study, we generated mice on an IL‐5Rα null background, each expressing a mutant form of an IL‐5Rα transgene ligated to a µ enhancer and VH promoter, either lacking the cytoplasmic DC3 region or substituting two proline residues for alanine (ApvA) in the membrane‐proximal ppvp motif of the cytoplasmic domain. The ppvp motif, which mediates activation of JAK2/STAT5 and Btk, also contributes to c‐fos, c‐jun and c‐myc expression. IL‐5Rα null mutant mice showed impaired B‐1‐cell development, reduced serum immunoglobulin G3 (IgG3) and IgM, no IL‐5‐induced enhancement of B‐cell proliferation and IL‐5‐induced switch recombination from the µ gene to γ1 gene; these were not recovered following the expression of the ApvA mutant. In contrast, absence of the DC3 region affected the IL‐5‐induced switch recombination from the µ to the γ1 gene and B‐1‐cell development, while IL‐5‐induced proliferation and IgM production were at levels similar to those of B cells expressing wild‐type IL‐5Rα transgene. The results clearly indicated that the ppvp motif and the DC3 region of IL‐5Rα played distinct roles in B‐cell proliferation and differentiation. Thus, this present approach offers new insights into the functions of the cytoplasmic subregions of IL‐5Rα, in particular its carboxy‐terminal region.
Role of oestrogen receptors α and β in immune organ development and in oestrogen‐mediated effects on thymus
Authors: Erlandsson Malin C. , Ohlsson Claes , Gustafsson Jan‐Åke , Carlsten Hans 
Published: March 2003

SummaryOestrogens affect the development and regulation of the immune system. To determine the role of oestrogen receptors α (ER‐α) and β (ER‐β) on the development of the immune system, male ER‐α (ERKO) and ER‐β (BERKO) mice, as well as αβ‐double knockout (DERKO) mice, were studied. Deletion of ER‐α led to hypoplasia of both thymus and spleen. Interestingly, a higher frequency of immature double CD4+ CD8+ thymocytes was found in ER‐α− mice compared with ER‐α+ mice. Female oophorectomized BERKO mice given oestradiol (E2) displayed a similar degree of thymic atrophy compared with the wild‐type strain but showed only limited involution of thymus cortex and no alteration of thymic CD4/CD8 phenotype expression. Our data demonstrate that expression of ER‐α, but not ER‐β, is mandatory in males for development of full‐size thymus and spleen, whereas expression of ER‐β is required for E2‐mediated thymic cortex atrophy and thymocyte phenotype shift in females. A potential background for the above findings may be down‐regulated activity in the growth hormone/insulin‐like growth factor‐1 (GH/IGF‐1) axis in males lacking ER‐α and suppressed sensitivity of females lacking ER‐β to E2‐mediated suppression of IGF‐1.
Acquisition of immune function during the development of the Langerhans cell network in neonatal mice
Authors: Dewar Andrea L. , Doherty Kathleen V. , Woods Gregory M. , Lyons A. Bruce , Muller H. Konrad 
Published: March 2003

SummaryThe immunological function of the Langerhans cell (LC) network in neonatal skin was examined by defining the development of cutaneous immunity relative to the structure, phenotype and function of the epidermal LC network in neonatal, juvenile and adult mice. Analysis of epidermal sheets showed the presence of major histocompatibility complex (MHC) II+, multilectin receptor DEC‐205– cells within the epidermis of 3‐day‐old mice; both cell density and DEC‐205 expression increased until day 14. When visualized with antibodies directed at MHC II, the network was poorly formed in 3‐ and 7‐day‐old mice, as there was a lower cell density and poor MHC II expression on dendritic processes, compared to mice at day14. Application of a fluorescent antigen to 3‐day‐old mice revealed that the LC were inefficient in transporting antigen to the draining lymph node. There was an improvement at day 7 and by day 14 comparable numbers of antigen carrying cells were detected in the lymph nodes of 6‐week‐old mice. The reduced antigen carriage in 3‐ and 7‐day‐old mice correlated with a poor contact sensitivity response. This was not simply due to failure to present antigen, but development of immunosuppression, as transfer of T cells from adult mice that were previously treated with antigen when they were 3 days old, to adult recipients resulted in antigen specific immunosuppression. Analysis of CD80 and CD86 expression showed that LC from day 3 skin expressed CD80, but not CD86 and application of antigen through this skin was inefficient in upregulating CD86. These findings indicate that when the neonatal LC network is poorly developed it is functionally immature and antigen applied through this ‘functionally immature network’ results in antigen specific immunosuppression.
Maternal tolerance is not critically dependent on interleukin‐4
Authors: Bonney Elizabeth A. 
Published: March 2003

SummaryPregnant animals can generate and maintain immune responses to fetal antigens. This however, does not usually lead to fetal loss. At least two types of immune response are recognized. T helper type 1 (Th1) responses support the generation of cellular cytotoxicity. In contrast, Th2‐type responses support the production of non‐cytotoxic antibody and suppress the Th1‐type. One attempt to explain why the fetus is not generally rejected has been to suggest that during pregnancy Th2‐type responses are dominant. These responses rely heavily on interleukin‐4 (IL‐4) for both functions. This work focuses on maternal immunity to the male antigen H‐Y, which is expressed in male fetuses. When injected with male spleen cells, female mice of certain strains mount a cytotoxic immune response to H‐Y. However, pregnant females immunized in this way do not deliver litters with fewer males. To help delineate the possible role of IL‐4 in such maternal tolerance, female mice genetically deficient in IL‐4 were studied. The results show that: (1) deficiency in maternal IL‐4 does not affect fertility, (2) deficiency in IL‐4 is not associated with selective loss of male offspring in unimmunized mice, (3) pregnancy does not obliterate anti‐H‐Y reactivity in immunized mice and (4) maternal immunity to H‐Y in the absence of IL‐4 does not result in loss of male offspring. The results suggest that IL‐4‐dependent Th2‐type responses are not critical to maternal tolerance. Other cytokines must be examined for their role in this phenomenon.
Nitric oxide protects cultured rheumatoid synovial cells from Fas‐induced apoptosis by inhibiting caspase‐3
Authors: Migita Kiyoshi , Yamasaki Satoshi , Kita Masako , Ida Hiroaki , Shibatomi Kazutaka , Kawakami Atsushi , Aoyagi Takahiko , Eguchi Katsuni 
Published: March 2003

SummaryNitric oxide (NO) is elevated in the synovial fluids and sera of patients with rheumatoid arthritis (RA) and is thought to be an important proinflammatory mediator in the rheumatoid synovium. To test the hypothesis that NO might modulate the apoptosis‐inducing signal pathway, we investigated the effects of NO on rheumatoid synovial‐cell apoptosis induced by Fas ligation with anti‐Fas antibody. Pretreatment of synovial cells with the NO donor S‐nitro‐N‐acetylpenicillamine (SNAP) prevented the Fas‐mediated induction of apoptosis. The activation of caspase‐3 was required to mediate Fas‐induced synovial cell apoptosis. The NO donor SNAP inhibited Fas‐induced caspase‐3 activation in rheumatoid synovial cells. However, NO did not interrupt Fas‐induced caspase‐8 cleavage or subsequent cytochrome c release into the cytosol in rheumatoid synovial cells. These data indicate that NO prevents apoptosis in rheumatoid synovial cells by directly inhibiting caspase‐3 activation. Thus, we propose that NO interferes with cell death signal transduction and may contribute to rheumatoid synovial cell proliferation by inhibiting induction of apoptosis.
Leucocyte recruitment during enteric nematode infection
Authors: McDermott Jacqueline R. , Grencis Richard K. , Else Kathryn J. 
Published: March 2003

SummaryResolution of infection with the intestinal nematode Trichinella spiralis depends on the host mounting a T helper 2 (Th2) response. It is known that both mast cells and T cells play a crucial role. We have previously shown that efficient migration of mast cells to the gut during infection depends on their expression of the integrin β7. β7 forms a heterodimer complex with either αE or α4 integrin chains, αEβ7 binding to E‐cadherin expressed by epithelial cells and α4β7 binding to mucosal addressin cell adhesion molecule (MAdCAM‐1) on the endothelium. We were interested to know whether dysfunctional mast cell localization to the gut in the absence of β7 was due to the failure of α4β7 to bind to MAdCAM‐1 or the failure of αEβ7 to bind to E‐cadherin. We used blocking monoclonal antibodies against αE (M290) or α4 (PS2) or β7 (HB293) during T. spiralis infection of C57BL/6 mice and found that all antibody treatments reduced mastocytosis. In contrast, none of the antibody treatments prevented the migration of CD3+ T cells into the intestine. These results indicate that during inflammation (a) there is integrin redundancy for lymphocytes but not for mast cells and (b) both αEβ7 and α4β7 are crucial either for the entry of mast cells into the gut or for their maturation once they have entered.
Acholeplasma laidlawii up‐regulates granulysin gene expression via transcription factor activator protein‐1 in a human monocytic cell line, THP‐1
Authors: Kida Yutaka , Kuwano Koichi , Zhang Ye , Arai Sumio 
Published: March 2003

SummaryAn antimicrobial protein granulysin is constitutively expressed in cytotoxic T lymphocytes (CTL) and natural killer (NK) cells. However, little is known about the precise regulatory mechanisms underlying granulysin gene expression. In this study, we examined the regulatory mechanisms underlying granulysin gene expression using a human monocytic cell line, THP‐1, treated with Acholeplasma laidlawii. The level of granulysin mRNA expression in THP‐1 cells was significantly augmented in response to stimulation with A. laidlawii. The transfection of reporter gene constructs into THP‐1 cells indicated that DNA sequences between residues −329 and −239, relative to the transcriptional start site of the granulysin gene, are responsible for mediating gene induction. In addition, mutagenesis of a putative activator protein‐1 (AP‐1)‐binding site between residues −277 and −271 in the granulysin promoter resulted in the reduction of granulysin promoter activity. Electrophoretic mobility shift assays (EMSA) demonstrated that nuclear extract prepared from A. laidlawii‐treated THP‐1 cells can generate specific binding to DNA oligonucleotides encompassing the AP‐1‐binding site, whereas unstimulated nuclear extract from the cells failed to do so. Furthermore, competition and supershift assays confirmed that A. laidlawii can induce the activation of AP‐1. These results indicate that AP‐1 dominantly participates in the regulation of inducible granulysin gene expression in THP‐1 cells. Therefore, the finding of inducible granulysin gene expression by A. laidlawii suggests that inducible granulysin in macrophages may function as a protective weapon when microbial invasion occurs.
Chemokine signalling: pivoting around multiple phosphoinositide 3‐kinases
Authors: Curnock Adam P. , Logan Marisa K. , Ward Stephen G. 
Published: March 2003

SummaryThe role of chemokines in mediating directional cell migration is well established, but more recently it has become evident that chemokines are able to couple to distinct signalling pathways that are involved in not only chemotaxis, but also cell growth and transcriptional activation. The signalling pathway controlled by the phosphoinositide 3‐kinase (PI3K) family of lipid kinases has been the focus of much attention with respect to their role in chemokine‐mediated functional responses. Indeed, there now exists convincing biochemical, pharmacological and genetic evidence that both CC and CXC chemokines stimulate PI3K‐dependent chemotaxis of inflammatory cells such as eosinophils, macrophages, neutrophils and T lymphocytes. This review considers the role of individual PI3Ks (e.g. the p85/p110 heterodimer, PI3Kγ and PI3KC2α) as well their downstream effector targets in mediating chemokine‐stimulated cell migration.
Distribution of IFN‐γ, IL‐4 and TNF‐α protein and CD8 T cells producing IL‐12p40 mRNA in human lung tuberculous granulomas
Authors: Fenhalls Gael , Stevens Liesel , Bezuidenhout Juanita , Amphlett Gillian E. , Duncan Ken , Bardin Philip , Lukey Pauline T. 
Published: March 2003

SummaryIn order to examine the immune response at the site of pathology in tuberculosis, we analysed cytokines present in lung granulomas, their associations with each other and with caseous necrosis as well as the phenotype of the cellular infiltrate. Paraffin‐embedded tissue from the lungs of seven patients with pulmonary tuberculosis was analysed by immunohistochemistry and in situ hybridization to detect interferon‐γ (IFN‐γ), tumour necrosis factor‐α (TNF‐α) and interleukin‐4 (IL‐4) proteins and IL‐12p40 mRNA. All seven patients had granulomas staining positive for IFN‐γ, TNF‐α and IL‐12p40, but only four stained positive for IL‐4. Cells with the morphology of lymphocytes, macrophages and giant cells expressed TNF‐α, IFN‐γ and IL‐4 protein. Furthermore, CD68‐positive myeloid cells expressed IL‐12p40 mRNA, as expected, but a subset of CD3‐positive lymphocytes also expressed this mRNA. These lymphocytes producing IL‐12p40 also stained positive for CD8 but not CD4. A total of 141 granulomas were scored for the presence or absence of cytokine or necrosis and two major associations were identified. The first association was between IFN‐γ and IL‐12, with 76% of granulomas staining positive for both cytokines. Unexpectedly, those granulomas positive for IL‐4 were always positive for IFN‐γ. The second association was between TNF‐α and caseous necrosis, where all necrotic granulomas were TNF‐α positive. This association was modulated by IL‐4. Therefore, heterogeneity of cellular infiltrate and cytokine expression is observed between adjacent granulomas in the same patient.
A cathelicidin family of human antibacterial peptide LL‐37 induces mast cell chemotaxis
Authors: Niyonsaba François , Iwabuchi Kazuhisa , Someya Akimasa , Hirata Michimasa , Matsuda Hiroshi , Ogawa Hideoki , Nagaoka Isao 
Published: March 2003

SummaryThe mast cell is one of the major effector cells in inflammatory reactions and can be found in most tissues throughout the body. During inflammation, an increase in the number of mast cells in the local milieu occurs, and such accumulation requires directed migration of this cell population. As it has previously been reported that the human cathelicidin‐derived antibacterial peptide, LL‐37, stimulates the degranulation of mast cells, we hypothesized that LL‐37 could be a mast cell chemotaxin. The present study shows that LL‐37 is a potent chemotactic factor for mast cells. The chemotactic response was dose‐dependent and bell‐shaped, reaching an optimal concentration of 5 µg/ml. In addition, checkerboard analysis showed that cell migration towards this peptide was chemotactic rather than chemokinetic. Moreover, Scatchard analysis using 125I‐labelled LL‐37‐derived peptide revealed that LL‐37 has at least two classes of receptors, namely high‐ and low‐affinity receptors, on mast cells. Furthermore, the competitive binding assay suggested that LL‐37 is unlikely to utilize formyl peptide receptor‐like 1 (FPRL1), a functional LL‐37 receptor for neutrophil and monocyte migration, on mast cells. In addition, the treatment of cells with pertussis toxin and phospholipase C inhibitor, U‐73122, inhibited LL‐37‐mediated migration, indicating that LL‐37 induces mast cell chemotaxis through a Gi protein‐phospholipase C signalling pathway. These results show that besides its antibacterial activities, LL‐37 may have the potential to recruit mast cells to inflammation foci.
T‐cell dynamics after high‐dose chemotherapy in adults: elucidation of the elusive CD8+ subset reveals multiple homeostatic T‐cell compartments with distinct implications for immune competence
Authors: Fagnoni Francesco F. , Lozza Laura , Zibera Carlo , Zambelli Alberto , Ponchio Luisa , Gibelli Nadia , Oliviero Barbara , Pavesi Lorenzo , Gennari Roberto , Vescovini Rosanna , Sansoni Paolo , Da Prada Gianantonio , Robustelli Della Cuna Gioacchino 
Published: March 2003

SummaryRecovery of total T cell numbers after in vivo T‐cell depletion in humans is accompanied by complex perturbation within the CD8+ subset. We aimed to elucidate the reconstitution of CD8+ T cells by separate analysis of putative naïve CD95− CD28+, memory CD95+ CD28+ and CD28− T cell compartments after acute maximal depletion by high‐dose chemotherapy (HD‐ChT) in women with high‐risk breast cancer. We found that recovery of putative naïve CD8+ CD95− CD28+ and CD4+ CD95− CD28+ T cells, was compatible with a thymus‐dependent regenerative pathway since their recovery was slow and time‐dependent, their values were tightly related to each other, and their reconstitution patterns were inversely related to age. By analysing non‐naïve T cells, a striking diversion between putative memory T cells and CD28− T cells was found. These latter increased early well beyond normal values, thus playing a pivotal role in total T‐cell homeostasis, and contributed to reduce the CD4 : CD8 ratio. In contrast, putative memory T cells returned to values not significantly different from those seen in patients at diagnosis, indicating that this compartment may recover after HD‐ChT. At 3–5 years after treatment, naïve T cells persisted at low levels, with expansion of CD28− T cells, suggesting that such alterations may extend further. These findings indicate that CD28− T cells were responsible for ‘blind’ T‐cell homeostasis, but support the notion that memory and naïve T cells are regulated separately. Given their distinct dynamics, quantitative evaluation of T‐cell pools in patients undergoing chemotherapy should take into account separate analysis of naïve, memory and CD28− T cells.
Involvement of ERK, p38 and NF‐κB signal transduction in regulation of TLR2, TLR4 and TLR9 gene expression induced by lipopolysaccharide in mouse dendritic cells
Authors: An Huazhang , Yu Yizhi , Zhang Minghui , Xu Hongmei , Qi Runzi , Yan Xiaoyi , Liu Shuxun , Wang Wenya , Guo Zhenghong , Guo Jun , Qin Zhihai , Cao Xuetao 
Published: March 2003

SummaryToll‐like receptors (TLR) are sentinel receptors capable of recognizing pathogen‐associated molecule patterns (PAMP) such as lipopolysaccharide (LPS) and CpG‐containing oligonucleotides (CpG ODN). TLR2 and TLR4 are major receptors for Gram‐positive and Gram‐negative bacterial cell wall components, respectively. TLR9 is necessary for CpG signalling. LPS or CpG ODN can activate immature dendritic cells (DC) and induce DC maturation characterized by production of cytokines, up‐regulation of co‐stimulatory molecules, and increased ability to activate T cells. However, little is known regarding the regulation of TLR gene expression in mouse DC. In this study, we investigated the regulation of TLR2, TLR4 and TLR9 gene expression by LPS in murine immature DC. TLR2, TLR4 and TLR9 mRNA were up‐regulated following LPS stimulation. The up‐regulation of TLR9 expression coincided with significantly increased production of tumour necrosis factor‐α induced by LPS plus CpG ODN. While inhibition of extracellular signal‐related kinase and NF‐κB activation suppressed the up‐regulation of the expression of TLR2, TLR4 and TLR9 mRNA, inhibition of p38 kinase prevented the up‐regulation of TLR2 and TLR4 mRNA expression but enhanced the up‐regulation of TLR9 expression. These results demonstrated that TLR2, TLR4 and TLR9 gene expression was differently regulated by LPS in mouse immature DC. Up‐regulation of TLR2, TLR4 and TLR9 expression by LPS might promote the overall responses of DC to bacteria and help to explain the synergy between LPS and other bacterial products in the induction of cytokine production.