bluuebunny/crossref_metadata_2025_split huggingface dataset:
Receptor‐mediated phagocytosis of rat macrophages is regulated differentially for opsonized particles and non‐opsonized particles containing β‐glucan
Authors: Reichner Jonathan S. , Fitzpatrick Paul A. , Wakshull Eric , Albina Jorge E. 
Published: March 2003

SummaryExperiments were conducted to test the hypothesis that opsonic and non‐opsonic phagocytic capacities are differentially regulated by resting and wound‐derived macrophages. Furthermore, the phagocytosis of non‐opsonized zymosan and β‐glucan particles was quantified to determine whether cells differentially regulate non‐opsonic lectinophagocytosis in accordance with the carbohydrate composition of the ligand. In that regard, wound macrophages exhibited profound differential regulation in lectinophagocytosis with a seven‐fold increase in phagocytosis of β‐glucan particles following overnight culture but with a relatively modest increase in internalization of mannan‐containing zymosan. Cultured peritoneal macrophages increased uptake of both particles similarly. Upon activation with interferon‐γ/lipopolysaccharide (IFN‐γ/LPS), wound macrophages selectively suppressed β‐glucan ingestion, while phagocytosis of zymosan particles was unaffected. Lectinophagocytosis was decreased in activated peritoneal macrophages regardless of particle composition and was due in part to a nitric oxide‐dependent mechanism which was without a role in regulation of wound macrophage lectinophagocytosis. Overnight culture of wound macrophages suppressed their capacity for opsonic‐dependent phagocytosis independently of activation, whereas suppression of phagocytosis by peritoneal macrophages was activation‐dependent. Regulation of all three phagocytic pathways was achieved distinctly by peritoneal and wound‐derived macrophages, with changes found in the percentage of resident peritoneal macrophages capable of phagocytosis, whereas the phagocytic capacity of wound macrophages was primarily affected by the number of particles ingested by individual cells. Taken together, these findings demonstrate that the differential regulation of phagocytic pathways encompasses the nature of the phagocytic particle, the site from which macrophages are obtained, their response to activating agents and the mechanism through which the cell population alters its phagocytic potential.
Interleukin‐12 stimulation of lymphoproliferative responses in Trypanosoma cruzi infection
Authors: Galvão da Silva Ana Paula , De Almeida Abrahamsohn Ises 
Published: March 2003

SummaryThe cytokine interleukin‐12 (IL‐12) is essential for resistance to Trypanosoma cruzi infection because it stimulates the synthesis of interferon‐γ (IFN‐γ), a major activator of the parasiticidal effect of macrophages. A less studied property of IL‐12 is its ability to amplify the proliferation of T or natural killer (NK) lymphocytes. We investigated the role of endogenously produced IL‐12 in the maintenance of parasite antigen (T‐Ag)‐specific lymphoproliferative responses during the acute phase of T. cruzi infection. We also studied whether treatment with recombinant IL‐12 (rIL‐12) would stimulate T‐Ag‐specific or concanavalin A (Con A)‐stimulated lymphoproliferation and abrogate the suppression that is characteristic of the acute phase of infection. Production of IL‐12 by spleen‐cell cultures during T. cruzi infection increased in the first days of infection (days 3–5) and decreased as infection progressed beyond day 7. The growth‐promoting activity of endogenous IL‐12 on T‐Ag‐specific proliferation was observed on day 5 of infection. Treatment of cultures with rIL‐12 promoted a significant increase in Con A‐stimulated proliferation by spleen cells from normal or infected mice. Enhanced T‐Ag‐specific proliferation by rIL‐12 was seen in spleen cell cultures from infected mice providing that nitric oxide production was inhibited by treatment with the competitive inhibitor NG‐monomethyl‐l‐arginine (NMMA). Enhancement of proliferation promoted by IL‐12 occurred in the presence of neutralizing anti‐interleukin‐2 (IL‐2) antibody, suggesting that this activity of IL‐12 was partly independent of endogenous IL‐2. Thymidine incorporation levels achieved with rIL‐12 treatment of the cultures were ≈ 50% of those stimulated by rIL‐2 in the same cultures.
Leishmania major lipophosphoglycan modulates the phenotype and inhibits migration of murine Langerhans cells
Authors: Ponte‐Sucre Alicia , Heise Dirk , Moll Heidrun 
Published: March 2003

SummaryLangerhans cells (LC), members of the dendritic cell family, play a central role in the initiation and regulation of the immune response against the protozoan parasite Leishmania major. LC take up antigens in the skin and transport them to the regional lymph nodes for presentation to T cells. However, it is not known whether LC functions are modulated by parasite antigens. In the present study, we examined the effect of a major parasite surface molecule, L. major lipophosphoglycan (LPG), on the maturation of LC and their migratory properties. The results show that exposure to LPG did not affect the expression of major histocompatibility complex (MHC) class II and B7, but induced an up‐regulation of CD25, CD31 and vascular endothelial (VE)‐cadherin expression and a down‐regulation of Mac‐1 expression, by LC. Importantly, LPG treatment inhibited the migratory activity of LC, as it reduced their efflux from skin explants and their migration in transwell cultures. These results suggest that Leishmania LPG impairs LC migration out of the skin and thus may modulate their immunostimulatory functions, which require LC translocation from skin to lymph nodes.
The regulation of DNAse activities in subcellular compartments of activated thymocytes
Authors: Nagata Takuya , Kishi Hiroyuki , Liu Qin Li , Matsuda Tadashi , Imanaka Tsuneo , Tsukada Kazuhiro , Kang Dongchon , Muraguchi Atsushi 
Published: March 2003

SummaryThymocytes expressing self‐reactive T‐cell receptors (TCR) are eliminated in the thymus through a TCR‐mediated signal. This cell death signal (negative selection) generates nuclear morphological change and DNA fragmentation in thymocytes. However, the pathway leading to DNA fragmentation of thymocytes following TCR engagement remains obscure. In this study, we investigated the localization and function of caspase‐activated DNAse (CAD) and its inhibitor (ICAD) in thymocytes prior to or after in vivo TCR stimulation. We showed that CAD and ICAD are co‐localized in microsome, nuclei and cytosol in unstimulated thymocytes. Following in vivo TCR engagement, ICAD located in cytosol and microsome was degraded and the resulting activated CAD induced chromosomal DNA fragmentation. CAD present in cytosol and microsome of unstimulated thymocytes was activated by recombinant caspase‐3, and microsomal CAD was released to the cytosol. These results demonstrate that TCR engagement of thymocytes induces caspase‐3‐dependent activation of CAD localized in both cytosol and microsome, leading to DNA fragmentation in harmony.
Roles of cytotoxic T‐lymphocyte‐associated antigen‐4 in the inductive phase of oral tolerance
Authors: Chen Yiguang , Ma Yuanfang , Chen Youhai 
Published: March 2003

SummaryTo elucidate the roles of cytotoxic T‐lymphocyte‐associated antigen‐4 (CTLA‐4) in oral tolerance, we studied the consequences of CTLA‐4 blockade during the inductive phase of oral tolerance using a transgenic T‐cell transfer model. We found that CTLA‐4 blockade significantly accelerated cell cycle progression of antigen‐specific T cells and dramatically increased their numbers in lymphoid organs following oral administration of ovalbumin (OVA). In mice fed with OVA, only ≈ 35% of specific T cells underwent more than four cycles of cell division. This was increased to 65% in mice fed with OVA and treated with a blocking anti‐CTLA‐4 monoclonal antibody (mAb). The OVA‐specific T cells in the latter group were localized primarily in the T‐cell zones of the mesenteric lymph nodes and Peyer's patches with a few penetrated into B‐cell follicles. Nevertheless, both faecal anti‐OVA immunoglobulin A (IgA) and seral anti‐OVA immunoglobulin G (IgG) were produced in anti‐CTLA‐4 mAb‐treated mice. These results suggest that CTLA‐4 limits the degree of T‐cell activation by blocking cell cycle progression during the inductive phase of oral tolerance. In the absence of the CTLA‐4 signal, mucosal exposure of antigen induces heightened T‐cell activation and expansion, which in turn promotes the production of antigen‐specific antibodies.
Identification and characterization of L‐selectin ligands in porcine lymphoid tissues
Authors: Khan Adil I. , Haskard Dorian O. , Malhotra Rajneesh , Landis R. Clive 
Published: March 2003

SummaryA human L‐selectin–ZZ fusion protein was used to screen porcine inguinal lymph nodes for the presence of monoclonal antibody (mAb) MECA 79‐negative ligands. Fractionation of lymph node‐conditioned medium by anion‐exchange chromatography revealed two distinct L‐selectin‐binding fractions, one containing a MECA 79 non‐reactive species and the second containing two MECA 79 reactive species of ≈ 84 000 and 210 000 molecular weight. The MECA 79 non‐reactive species exhibited Ca2+‐ and lectin‐dependent binding to L‐selectin–ZZ in a solid‐phase capture enzyme‐linked immunosorbent assay (ELISA), and this was specifically disrupted by the addition of EDTA, mannose‐6‐phosphate and the blocking anti‐L‐selectin mAb, DREG‐56. Enzymatic characterization of the ligand by trypsin, O‐sialoglycoprotease endopeptidase, heparinases I and III, or chondroitinase ABC lyase digestion indicated that L‐selectin binding was predominantly dependent upon a chondroitin sulphate‐modified glycoprotein determinant. Although Coomassie Blue staining of sodium dodecyl sulphate (SDS) polyacrylamide gels did not reveal a detectable protein species, carbohydrate‐specific staining using GlycoTrack™ revealed a single, heavily glycosylated protein of high molecular weight (> 220 000). These studies have revealed the existence of a MECA 79 non‐reactive, chondroitin sulphate glycosaminoglycan‐modified ligand, termed csgp>220, which is secreted by peripheral lymph nodes and may play a role in leucocyte trafficking to the lymph node.
Cross‐reactivity of the anti‐La monoclonal antibody SW5 with early endosome antigen 2
Authors: A. Fouraux Michael , Heijden Annemarie van der , Van Venrooij Walther J. , Pruijn Ger J. M. 
Published: March 2003

SummaryCoimmunoprecipitation studies with SW5, a frequently used and specific mouse monoclonal antibody (mAb) directed against the human La autoantigen, led to the identification of a functionally unrelated 80 000 MW protein, designated early endosome antigen 2 (EEA2). EEA2 appeared to be directly targeted by mAb SW5. Because an RNA‐binding domain, a structural element of La containing the SW5‐epitope, was not discernable in the primary structure of EEA2, the SW5‐epitope on EEA2 was determined. Coiled‐coil region 3 of EEA2 appeared to contain the epitope recognized by SW5. The SW5 epitope regions of La and EEA2 share a limited sequence homology and probably share a higher degree of structural similarity at the tertiary level. Most likely, the most critical determinants for recognition by SW5 reside in elements adopting alpha‐helical conformations. These data indicate that the application of specific mAbs to purify and characterize (functionally) interacting proteins can be severely obscured by the cross‐reactivity of mAbs with structurally, but not functionally, similar proteins.
A new Groucho TLE4 protein may regulate the repressive activity of Pax5 in human B lymphocytes
Authors: Milili Michèle , Gauthier Laurent , Veran Julie , Mattei Marie‐Geneviève , Schiff Claudine 
Published: March 2003

SummaryDuring mouse B‐cell development, Pax5 is an essential transcription factor that acts as an activator of B‐cell‐specific genes and as a repressor of alternative lineage fates. The repressive function is mediated by the recruitment of members of the Groucho co‐repressor family. Using an RNA display approach, we have isolated a transcript, called QD, specifically expressed in human pro‐B and pre‐B cells, which is derived from the human Groucho TLE4 gene. The QD transcript contains the first four TLE4 exons and an intronic sequence 3′ of exon 4, demonstrating that QD is a splice variant of TLE4. The putative resulting protein of 94 amino acids corresponds to approximately half of an N‐terminal tetramerization domain. We also show specific expression of TLE4 transcripts in human B cells and of TLE4 proteins in B‐cell nuclei. Moreover, we demonstrate that recombinant QD protein binds to the TLE4 Q domain and is able to abolish the TLE4/Pax5 interaction. Thus, QD could act as a negative regulator of TLE4 function, in early B‐cell differentiation.
Significant role of Fas ligand‐binding but defective Fas receptor (CD95) in lymph node hyperplasia composed of abnormal double‐negative T cells
Authors: Matsuzawa Akio , Shimizu Motomu , Takeda Yasutaka , Nagase Hisashi , Sayama Kazutoshi , Kimura Mikio 
Published: March 2003

SummaryThe functional differences between two mutations of the Fas (CD95) locus, Faslpr (lpr) and Faslprcg (lprcg), were investigated using bone marrow (BM) transplantation on the C3H mouse background. Both lpr/lpr and lprcg/lprcg BM transferred caused lymph node (LN) hyperplasia in lpr/+ and lprcg/+ recipients, although it was clearly smaller than that in lpr/lpr and lprcg/lprcg recipients of lpr/lpr and lprcg/lprcg BM. In addition, both BM induced significantly larger LN hyperplasia in lprcg/+ than lpr/+ recipients. Appearance of CD4− CD8−[double negative (DN)] T cells in the periphery is the most consistent phenotype of Fas mutations. Importantly, the proportion of DN T cells was higher in larger LN hyperplasia in the order of lpr/+, lprcg/+ and lpr/lpr or lprcg/lprcg recipients. On the other hand, both lpr/lpr and lprcg/lprcg BM transferred into wild‐type (+/+) mice caused marked LN atrophy. The former, but not the latter, induced wasting syndrome. Faslg1d (gld)‐homozygous lpr/lpr BM transferred into +/+ mice elicited LN hyperplasia of the same extent as that in lpr/lpr mice transferred with lpr/lpr BM, but not wasting syndrome. Taken together with the fact that DN T cells massively express Fas ligand (FasL), this study implied that FasL overexpressed on DN cells may be involved in the accumulation of DN T cells in LN, LN atrophy and wasting syndrome, and that lprcg Fas, which can bind to Fas ligand but not transduce apoptosis signal into cells, may modulate these pathological conditions by interfering with the binding of FasL to Fas.
Interaction between nitric oxide and subsets of human T lymphocytes with differences in glutathione metabolism
Authors: Roozendaal Ramon , Kauffman HENK F. , Dijkhuis Anne‐Jan , Ommen Elisabeth T. V. , Postma Dirkje S. , De Monchy Jan G. R. , Vellenga Edo 
Published: March 2003

SummaryNitric oxide (NO) modulates human T‐lymphocyte responses through several mechanisms. In the current study we show that interactions between NO and glutathione (GSH) metabolism are related to the selective persistent inhibition of interferon‐γ (IFN‐γ) production by NO, which we previously identified. T cells were exposed to NO using the NO‐donor compound Spermine‐nonoate (Sper) and activated using anti‐CD3 plus anti‐CD28 monoclonal antibodies. Persistent inhibition of IFN‐γ by Sper was prevented by addition of the GSH precursor l‐cysteine, which inhibits Sper induced GSH depletion. Subsets of cells were either susceptible (GSHlow) or resistant (GSHhigh) to NO‐induced GSH depletion. The GSHlow subset was characterized by enhanced numbers of CD4+ cells, reduced numbers of activated cells as characterized by CD25 and CD69, and reduced numbers of memory (CD45RO+) cells relative to the GSHhigh population. Rather than directly affecting susceptibility to NO, these surface markers reflected different expression patterns. Particularly, the GSHlow subset was further characterized by decreased activity of the GSH synthesis related enzymes multi‐drug resistance related protein (MRP)‐1 and γ‐glutamyltranspeptidase (γ‐GT). Blocking γ‐GT, using acivicin was shown to exacerbate NO‐induced GSH depletion and NO‐induced apoptosis. Since NO induced apoptosis selectively affects IFN‐γ production these findings implicate GSH metabolism in the modulation and maintenance of the T helper (Th)1/Th2 balance.
In vivo maintenance of T‐lymphocyte unresponsiveness induced by thymic medullary epithelium requires antigen presentation by radioresistant cells
Authors: Hudrisier Denis , Feau Sonia , Bonnet Véronique , Romagnoli Paola , Van Meerwijk Joost P. M. 
Published: March 2003

SummaryThe T‐cell repertoire developing in the thymus is rid of autospecific cells by the process of thymic negative selection. Recognition of major histocompatibility complex (MHC)/self‐peptide complexes expressed by thymic antigen‐presenting cells (APC) of bone marrow origin leads to induction of apoptotic death of autospecific thymocytes. Induction of tolerance to self‐antigens not presented by thymic APC is mediated by medullary thymic epithelial cells (mTEC) which express a very wide range of proteins, e.g. inducible and tissue‐specific proteins. The main type of tolerance induced by mTEC is non‐deletional and the issue of how it is maintained outside the thymus is therefore of crucial interest. We have previously shown that the non‐T‐cell receptor (TCR) ‐transgenic T‐cell repertoire developing in conditions in which tolerance to self‐MHC/peptide ligands is exclusively induced by mTEC is tolerant to syngeneic targets in vivo but lyses such targets in vitro. Here we report that this non‐deletional in vivo self‐tolerance is not due to active tolerance assured by known naturally occurring regulatory or immune‐modulating T lymphocytes. Importantly, we show that in vivo maintenance of this therefore probably anergic state requires continued interaction of autospecific T cells with self‐MHC/peptide ligands expressed by radioresistant cells while APC are incapable of maintaining the tolerant state. Therefore, maintenance of non‐deletional T‐lymphocyte tolerance to the wide range of self‐antigens expressed by mTEC depends on continued interaction with radioresistant cells that very probably express a much more limited repertoire of antigens. Our data may therefore have important consequences for tolerance to tissue‐specific and inducible self‐antigens.
Form and pattern of MUC1 expression on T cells activated in vivo or in vitro suggests a function in T‐cell migration
Authors: Correa Isabel , Plunkett Tim , Vlad Anda , Mungul Arron , Candelora‐Kettel Jessica , Burchell Joy M. , Taylor–papadimitriou Joyce , Finn Olivera J. 
Published: March 2003

SummaryMUC1 is a transmembrane mucin that is expressed on ductal epithelial cells and epithelial malignancies and has been proposed as a target antigen for immunotherapy. The expression of MUC1 has recently been reported on T and B cells. In this study we demonstrate that following activation in vivo or activation by different stimuli in vitro, human T cells expressed MUC1 at the cell surface. However, the level of expression in activated human T cells was significantly lower than that seen on normal epithelial cells or on breast cancer cells. In contrast, resting T cells did not bind MUC1‐specific monoclonal antibodies (mAbs), nor was MUC1 mRNA detectable by reverse transcription–polymerase chain reaction (RT–PCR) or Northern blot analysis in these cells. The profile of activated T‐cell reactivity with different MUC1‐specific antibodies suggested that the glycoform of MUC1 expressed by the activated T cells carried core 2‐based O‐glycans, as opposed to the core 1 structures that dominate in the cancer‐associated mucin. Confocal microscopy revealed that MUC1 was uniformly distributed on the surface of activated T cells. However, when the cells were polarized in response to a migratory chemokine, MUC1 was found on the leading edge rather than on the uropod, where other large mucin‐like molecules on T cells are trafficked. The concentration of MUC1 at the leading edge of polarized activated human T cells suggests that MUC1 could be involved in early interactions between T cells and endothelial cells at inflammatory sites.
An abnormal but functionally active complement component C9 protein found in an Irish family with subtotal C9 deficiency
Authors: Orren Ann , O'Hara Ann M. , Morgan B. Paul , Moran Anthony P. , Würzner Reinhard 
Published: March 2003

SummaryTwo independently segregating C9 genetic defects have previously been reported in two siblings in an Irish family with subtotal C9 deficiency. One defect would lead to an abnormal C9 protein, with replacement of a cysteine by a glycine (C98G). The second defect is a premature stop codon at amino acid 406 which would lead to a truncated C9. However, at least one of two abnormal proteins was present in the circulation of the proband at 0·2% of normal C9 concentration. In this study, the abnormal protein was shown to have a molecular weight approximately equal to that of normal C9, and to carry the binding site for monoclonal antibody (mAb) Mc42 which is known to react with an epitope at amino acid positions 412–426, distal to 406. Therefore, the subtotal C9 protein carries the C98G defect. The protein was incorporated into the terminal complement complex, and was active in haemolytic, bactericidal and lipopolysaccharide release assays. A quantitative haemolytic assay indicated even slightly greater haemolytic efficiency than normal C9. Epitope mapping with six antihuman C9 mAbs showed the abnormal protein to react to these antibodies in the same way as normal C9. However, none of these mAbs have epitopes within the lipoprotein receptor A module, where the C98G defect is located. The role of this region in C9 functionality is still unclear. In conclusion, we have shown that the lack of a cysteine led to the production of a protein present in the circulation at very much reduced levels, but which was fully functionally active.
Transforming information systems development through computer‐aided systems engineering (CASE): lessons from practice
Authors: Butler Tom 
Published: March 2003

Abstract.In dealing with the challenges posed by the ongoing problem of developing and integrating an evermore complex and diverse range of information systems in a timely manner, practitioners continue to grapple with important issues such as increasing developer productivity and bringing quality improvements to the process and product of systems development. Many organizations have adopted computer‐aided systems engineering (CASE) tools with such outcomes in mind. With few exceptions, previous research into the phenomenon of CASE adoption and use has been survey based in the main, and has resulted in some confusion over the benefits to be derived from the use of CASE tools within the systems development process. This paper extends previous work as part of an interpretive, case‐based research strategy to examine the adoption and use of integrated CASE (I‐CASE) in a single organization. Such an approach facilitates a deeper understanding of the impact that CASE exerts on the process and product of systems development. Based on the experience of practitioners in the organization studied, a set of recommendations is presented. The findings of this study also lend support to the view that an I‐CASE development platform does indeed have the potential to exert a positive impact on the development process and its product.