bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selectively impaired development of intestinal T cell receptor γδ+ cells and liver CD4+ NK1+ T cell receptor αβ+ cells in T cell factor‐1‐deficient mice
Authors: Ohteki Toshiaki , Wilson Anne , Verbeek Sjef , MacDonald H. Robson , Clevers Hans 
Published: March 2007

AbstractT cell factor‐1 (Tcf‐1) is a transcription factor that binds to a sequence motif present in several T cell‐specific enhancer elements. In Tcf‐1‐deficient (Tcf‐1−/‐) mice, thymocyte development is partially blocked at the transition from the CD4−8+ immature single‐positive stage to the CD4+8+ double‐positive stage, resulting in a marked decrease of mature peripheral T cells in lymph node and spleen. We report here that the development of most intestinal TCRγδ+ cells and liver CD4+ NK1.1+TCRαβ+ (NK1+T) cells, which are believed to be of extrathymic origin, is selectively impaired in Tcf‐1−/‐ mice. In contrast, thymic and thymus‐derived (splenic) TCRγδ+ cells are present in normal numbers in Tcf‐1−/‐ mice, as are other T cell subsets in intestine and liver. Collectively, our data suggest that Tcf‐1 is differentially required for the development of some extrathymic T cell subsets, including intestinal TCRγδ+ cells and liver CD4+ NK1+ T cells.
Administration of interleukin‐10 abolishes innate resistance to Listeria monocytogenes
Authors: Kelly John P. , Bancroft Gregory J. 
Published: March 2007

AbstractWe have used severe‐combined immunodeficient (SCID) mice to examine the immunoregulatory effects of interleukin (IL)‐10 on innate resistance to infection with Listeria monocytogenes. Addition of heat killed Listeria to spleen cells from naive SCID mice resulted in secretion of interferon (IFN)‐γ from natural killer cells in vitro. This response was enhanced up to 15‐fold in the presence of exogenous IL‐2, but was completely ablated by addition of IL‐10 with an IC50 of < 0.5 U/ml. Infection of SCID mice with viable Listeria in vivo resulted in a prolonged course of infection eventually causing death by 12–14 days, whereas daily administration of IL‐10 increased bacterial replication in the liver and spleen by up to 1000‐fold resulting in death by day 4 post‐infection. The immunosuppressive actions of IL‐10 in vivo were also observed in immunocompetent BALB/c mice, where doses as low as 100 U/day converted a sublethal infection to 100% mortality. To study the events controlling expression of endogenous IL‐10, peritoneal macrophage monolayers were challenged with Listeria after pre‐incubation with a panel of recombinant cytokines. IFN‐γ primed macrophages for enhanced tumor necrosis factor (TNF) secretion, but inhibited IL‐10 production, whereas granulocyte/macrophage colony‐stimulating factor (CSF), macrophage CSF and also IL‐4 enhanced macrophage IL‐10 responses after ingestion of Listeria in vitro. Finally, monoclonal antibody neutralization of IFN‐γ during infection of SCID mice with Listeria inhibited TNF‐α mRNA, but augmented expression of IL‐10 mRNA in infected tissues. These results demonstrate that exogenous IL‐10 is a potent immunosuppressive cytokine in the context of infection with an intracellular bacterium and that expression of endogenous IL‐10 versus TNF is differentially regulated by the cytokine environment of the macrophage.
CD40/CD40 ligand interactions are required for T cell‐dependent production of interleukin‐12 by mouse macrophages
Authors: Kennedy Mary K. , Picha Kathleen S. , Fanslow William C. , Grabstein Kenneth H. , Alderson Mark R. , Clifford Ky N. , Chin Wilson A. , Mohler Kendall M. 
Published: March 2007

AbstractWe have previously shown that T cell receptor‐activated mouse T helper (Th)1 clones induce the production of interleukin (IL)‐12 by splenic antigen‐presenting cells (APC). Here, we show that the expression of CD40L by activated T cells is critical for T cell‐dependent IL‐12 production by mouse macrophages. IL‐12 was produced in cultures containing alloreactive Th1 clones stimulated with allogeneic peritoneal macrophages, or in cultures of splenocytes stimulated with anti‐CD3. Anti‐CD40L monoclonal antibodies (mAb) inhibited the production of IL‐12, but not IL‐2, in these cultures by ⩾90% and had dramatic inhibitory effects on antigen‐dependent proliferation of Th1 clones. In addition, both activated T cells and a Th1 clone derived from CD40L knockout mice failed to induce IL‐12 production from splenic APC or peritoneal macrophages. Finally, macrophages cultured in the absence of T cells produced IL‐12 upon stimulation with soluble recombinant CD40L in combination with either supernatants from activated Th1 clones or with interferon‐γ and granulocyte/macrophage colony‐stimulating factor. Thus, both CD40L‐dependent and cytokine‐mediated signals from activated T cells are required to induce the production of IL‐12 by macrophages. A blockade at the level of IL‐12 production may explain, at least in part, the dramatic ability of anti‐CD40L mAb to inhibit disease in animal models that are dependent upon the generation of a cell‐mediated immune response. Moreover, a defect in T cell‐dependent induction of IL‐12 may contribute to the immune status of humans that lack functional CD40L.
A study of complexes of class II invariant chain peptide: Major histocompatibility complex class II molecules using a new complex‐specific monoclonal antibody
Authors: Eastman Susan , Deftos Michael , Deroos Paul C. , Hsu Di‐Hwei , Teyton Luc , Braunstein Ned S. , Hackett Charles J. , Rudensky Alexander 
Published: March 2007

AbstractComplexes of major histocompatibility complex (MHC) class II molecules containing invariant chain (Ii)‐derived peptides, known as class II‐associated invariant chain peptides (CLIP), are expressed at high levels in presentation‐deficient mutant cells. Expression of these complexes in mutant and wild‐type antigen‐presenting cells suggests that they represent an essential intermediate in the MHC class II antigen‐presenting pathway. We have generated a monoclonal antibody, 30‐2, which is specific for these complexes. Using this antibody, we have found quantitative differences in CLIP: MHC class II surface expression in mutant and wild‐type cells. Our experiments also show that CLIP: MHC class II complexes are preferentially expressed on the cell surface similar to total mature MHC class II molecules. These complexes are found to accumulate in the endosomal compartment in the process of endosomal Ii degradation. Analysis of the fine specificity of the antibody indicates that these complexes have Ii peptide bound to the peptide‐binding groove.
Membrane exon sequences of the three Xenopus Ig classes explain the evolutionary origin of mammalian isotypes
Authors: Mußmann Rainer , Wilson Melanie , Marcuz Anne , Courtet Michèle , Du Pasquier Louis 
Published: March 2007

AbstractWe have cloned and sequenced the genes corresponding to the membrane exons of the three immunoglobulin (Ig) heavy chain isotypes (μ, ν and χ) of Xenopus. Among membrane Ig (mIg) polypeptides, the transmembrane domain are the most highly conserved. The transmembrane and cytoplasmic domains of Xenopus mIgM are similar to the corresponding domains of all known vertebrate mIgM molecules, supporting the idea that amphibian μ gene is homologous, not just analogous, to the μ gene of higher vertebrates. The membrane forms of the two other Ig isotypes mIgX and mIgY exhibit the specific structure found in all Ig membrane exons, but are not homologous with any specific mammalian non‐μ Ig isotype; they are most similar to Xenopus mIgM. Based on the conserved transmembrane domains of Xenopus mIgX, mIgY, we suggest that first the ν and later the χ genes arose by duplication from the original μ gene. The transmembrane and the 37‐amino‐acid‐long cytoplasmic domains of Xenopus mIgY have conserved residues found in avian mIgY and mammalian mIgG and mIgE, suggesting that the modern isotypes might share a common ancestor with amphibian mIgY. However, while the sequence similarity between the membrane exons of avian mIgY and mammalian mIgG and IgE is striking, the overall similarity with Xenopus mIgY is very low. Thus, the genes giving rise to Xenopus mIgY and those eventually leading to avian mIgY and mammalian mIgG and mIgE must have diverged early in evolution, probably at the level of the primitive amphibians or before.
Expression and function of B7‐1 (CD80) and B7‐2 (CD86) on human epidermal Langerhans cells
Authors: Rattis Frédérique‐Marie , Péguet‐Navarro Josette , Staquet Marie‐Jeanne , Dezutter‐Dambuyant Colette , Courtellemont Pascal , Redziniak Gérard , Schmitt Daniel 
Published: March 2007

AbstractIn addition to T cell receptor triggering, activation of T cells requires co‐stimulatory signals that have been shown to be mainly initiated through CD28. We analyzed the expression and function of the two ligands for CD28, B7‐1 (CD80) and B7‐2 (CD86), on human Langerhans cells (LC), the antigen‐presenting cells from epidermis. Human LC freshly isolated from epidermis (fLC) expressed significant level of B7‐2, which was increased upon a short culture in vitro. In contrast, B7‐1 was undetectable on fLC but appeared at the cell surface after a 3‐day culture in vitro. Pre‐incubation of 18‐h cultured LC with anti‐B7‐2 monoclonal antibodies (mAb) was sufficient to abrogate the binding of CTLA4‐Ig fusion protein, while a combination of both mAb against B7‐1 and B7‐2 was necessary to obtain a complete inhibition of CTLA4‐Ig binding on 3‐day cultured LC, showing the absence of a third CTLA4 ligand. The function of B7‐1 and B7‐2 on human LC has been analyzed by adding mAb at the beginning of mixed epidermal cell lymphocyte reactions. Anti‐B7‐2 mAb and CTLA4‐Ig, but not anti‐B7‐1 mAb, strongly inhibited allogeneic, as well as recall antigen‐induced T cell proliferation supported by fLC or 3‐day cultured LC. Collectively, these results demonstrate that B7‐2 is the major ligand for CD28/CTLA4 at the LC surface and that it plays a crucial role in human LC co‐stimulatory function with little, if any, dependence on B7‐1 expression.
P‐selectin directs T lymphocyte‐mediated injury in delayed‐type hypersensitivity responses: studies in glomerulonephritis and cutaneous delayed‐type hypersensitivity
Authors: Tipping Peter G. , Huang Xiao R. , Berndt Michael C. , Holdsworth Stephen R. 
Published: March 2007

AbstractThe role of P‐selectin in T lymphocyte accumulation and injury was studied in delayed‐type hypersensitivity (DTH) responses in the skin and glomeruli of rats. Sprague Dawley rats were sensitized to sheep globulin and challenged 5 days later in the skin by subcutaneous injection and simultaneously in glomeruli by intravenous injection of a subnephritogenic dose of sheep anti‐rat glomerular basement membrane globulin. This resulted in cutaneous and glomerular T lymphocyte‐dependent macrophage influx and injury characteristic of DTH. Up‐regulation of P‐selectin expression on endothelial cells was observed in both inflammatory lesions. Treatment of rats with anti‐CD5 antibody immediately prior to antigen challenge prevented the development of injury as assessed by measurement of proteinuria and skin swelling, as well as local T cell and macrophage accumulation in the glomerulus and in the skin, but did not block up‐regulation endothelial cell P‐selectin. Treatment with anti‐CD4 antibody produced similar results. Blocking P‐selectin in vivo with a functionally inhibitory antibody prevented development of proteinuria and skin swelling following antigen challenge. Local accumulation of T cells and macrophages was markedly attenuated in glomeruli and the skin and up‐regulation of endothelial cell P‐selectin was prevented. These data demonstrate that P‐selectin is locally up‐regulated on endothelial cells in T cell‐dependent glomerular and cutaneous inflammation and suggests a pivotal functional role for P‐selectin in local T cell recruitment and subsequent injury in DTH.
Anti‐parasitic effector mechanisms in human brain tumor cells: Role of interferon‐γ and tumor necrosis factor‐α
Authors: Däubener Walter , Remscheid Christine , Nockemann Susanne , Pilz Korinna , Seghrouchni Samira , Mackenzie Colin , Hadding Ulrich 
Published: March 2007

AbstractToxoplasma gondii, an obligate intracellular parasite, is able to replicate in human brain cells. We recently showed that interferon (IFN)‐γ‐activated cells from glioblastoma line 86HG39 were able to restrict Toxoplasma growth. The effector mechanism responsible for this toxoplasmostatic effect was shown by us to be the IFN‐γ‐mediated activation of indolamine 2,3‐dioxygenase (IDO), resulting in the degradation of the essential amino acid tryptophan. In contrast, glioblastoma 87HG31 was unable to restrict Toxoplasma growth after IFN‐γ activation, and IFN‐γ‐mediated IDO activation was weak. We observed that tumor necrosis factor (TNF)‐α alone is unable to activate IDO or to induce toxoplasmostasis in any glioblastoma cell line tested. Interestingly, we found that TNF‐α and IFN‐γ were synergistic in the activation of IDO in glioblastoma cells 87HG31, 86HG39 and U373MG and in native astrocytes. This was shown by the measurement of enzyme activity as well as by the detection of IDO mRNA in TNF‐α + IFN‐γ activated cells. This IDO activity results in a strong toxoplasmostatic effect mediated by glioblastoma cells activated simultaneously by both cytokines. Antibodies directed against TNF‐α or IFN‐γ were able to inhibit IDO activity as well as the induction of toxoplasmostasis in glioblastoma cells stimulated with both cytokines. Furthermore, it was found that the addition of L‐tryptophan to the culture medium completely blocks the antiparasitic effect. We therefore conclude that both TNF‐α and IFN‐γ may be involved in the defense against cerebral toxoplasmosis by inducing IDO activity as an antiparasitic effector mechanism in brain cells.
Immunization with glycosylated Kb‐binding peptides generates carbohydrate‐specific, unrestricted cytotoxic T cells
Authors: Abdel‐Motal Ussama M. , Berg Louise , Rosén Anders , Bengtsson Marita , Thorpe Cristopher J. , Kihlberg Jan , Dahmén Jan , Magnusson Göran , Karlsson Karl‐Anders , Jondal Mikael 
Published: March 2007

AbstractCytotoxic T cells (CTL) recognize target proteins as short peptides presented by major histocompatibility complex (MHC) class I restriction elements. However, there is also evidence for peptide‐independent T cell receptor (TCR) recognition of target proteins and non‐protein structures. How such T cell responses are generated is presently unclear. We generated carbohydrate (CHO)‐specific, MHC‐unrestricted CTL responses by coupling di‐ and trisaccharides to Kb‐ or Db‐binding peptides for direct immunization in mice. Four peptides and three CHO have been analyzed with the CHO either in terminal or central positions on the carrier peptide. With two of these glycopeptides, with galabiose (Galα1‐4Gal; Gal2) bound to a homocysteine (via an ethylene spacer arm) in position 4 or 6 in a vesicular stomatitis virus nucleoprotein‐derived peptide (RGYVYQGL binding to Kb), CTL were generated which preferentially killed target cells treated with glycopeptide compared to those treated with the core peptide. Polyclonal CTL were also found to kill target cells expressing the same Gal2 epitope in a glycolipid. By fractionation of CTL, preliminary data indicate that glycopeptide‐specific Kb‐restricted CTL and unrestricted CHO‐specific CTL belong to different T cell populations with regard to TCR expression. The results demonstrate that hapten‐specific unrestricted CTL responses can be generated with MHC class I‐binding carrier peptides. Different models that might explain the generation of such responses are discussed.
Interleukin‐5 mRNA expressed by eosinophils and γ/δ T cells in parasite‐immune sheep
Authors: Bao Shisan , McClure Susan J. , Emery David L. , Husband Alan J. 
Published: March 2007

AbstractInterleukin (IL)‐5 is produced by a variety of cell types and contributes to both lymphocyte development and eosinophil terminal differentiation in vitro. The coincidence of worm expulsion and eosinophilia in sheep infected with the gastrointestinal nematode Trichostrongylus colubriformis suggests that eosinophils may be involved as effector cells in host immunity against parasite infection. The role of IL‐5 in this process was investigated by observing the distribution of IL‐5 mRNA+ cells in the small intestine, mesenteric lymph nodes (MLN) and Peyer's patches (PP) by an in situ hybridization technique using a murine IL‐5 riboprobe. IL‐5 mRNA+ cells were distributed throughout the lamina propria (LP) of the small intestine from the tips of the villi to the muscularis mucosae and in the parafollicular areas of MLN and PP in both naive and immune sheep. The phenotypes of IL‐5 mRNA+ cells was explored by simultaneous eosin and immunohistochemical staining using a monoclonal antibody recognizing the T19 marker, which identifies a major subset of γ/α TCR+ cells in sheep. In immune sheep, there was about a five‐fold increase in the number of eosinophils and IL‐5 mRNA+ cells in the LP, but there was no significant change in numbers of T19+ cells. Most of the IL‐5 mRNA+ cells in the LP were eosinophils, but many of the T19+ cells also expressed IL‐5 mRNA. In contrast, there were fewer eosinophils than T19+ cells in MLN of immune sheep and, compared to controls, a threefold increase in T19+ cells and a five‐fold increase in T19+/IL‐5 mRNA+ double‐positive cells was observed in immune sheep. In PP, there were very few eosinophils but substantial numbers of T19+ cells; however, no significant differences in numbers of eosinophils, T19+ or IL‐5 mRNA+ cells were observed between control and immune sheep. These results indicate that in sheep, both eosinophils and γ/δ T cells are capable of IL‐5 expression and suggest that IL‐5 is an important regulatory factor in autocrine and paracrine activation of effector cells involved in parasite immune expulsion.
Mycobacteria‐reactive γδ T cells in HIV‐infected individuals: lack of Vγ9 cell responsiveness is due to deficiency of antigen‐specific CD4 T helper type 1 cells
Authors: Wesch Daniela , Kabelitz Dieter , Friese Klaus , Pechhold Klaus 
Published: March 2007

AbstractHuman γδ T lymphocytes expressing the variable T cell receptor elements Vγδ paired with Vδ2 are activated by antigen derived from Mycobacterium tuberculosis (M. tb.) and presented by antigen‐presenting cells (APC). The subsequent proliferation is strictly dependent on the presence of CD4+TCRαβ+ T helper type 1 (Th1) cells producing interleukin‐2 (IL‐2). In this study, we report that the reactivity of Vγ9 cells to M. tb. stimulation in vitro was drastically decreased or absent in the majority of the analyzed HIV‐1‐infected individuals (CDC stages III and IV). We show that the failure of Vγ9 cells frim HIV− individuals to proliferate following M. tb. stimulation was not due to an intrinsic qualitative or quantitative defect of γδ T cells but rather to a deficiency of M. tb.‐reactive CD4 Th1 cells. Thus, Vγ9 responsiveness could be restored if cultures of M. tb.‐stimulated T cells from HIV+ donors were reconstituted with one of the following: (i) exogenous IL‐2; (ii) purified CD4T cells from allogeneic donors; or (iii) T cell‐depleted APC from allogeneic donors. In the majority of HIV+ patients, the defective Th1 activity of M. tb.‐stimulated CD4 T cells could be increased neither by cytokines known to favor Th1 development (IL‐12, interferon‐γ) nor by neutralization of the Th1‐suppressing Th2 cytokine IL‐10. We suggest that measurement of Vγ9 cell expansion within M. tb.‐stimulated peripheral blood mononuclear cells provides a sensitive assay for the functional capacity of antigen (M. tb.)‐specific CD4 Th1 cells in HIV‐infected individuals.
Macrophage‐T cell interaction in murine salmonellosis: selective down‐regulation of ICAM‐1 and B7 molecules in infected macrophages and its probable role in cell‐mediated immunity
Authors: Gupta Sudhir , Vohra Harpreet , Saha Bhaskar , Nain Chander Kanwal , Ganguly Nirmal Kumar 
Published: March 2007

AbstractVaccine development and understanding of cellular immune modulatory mechanisms in salmonella infections have been impeded due to the paucity of data on antigens capable of eliciting effective immune responses. The present study was done to evaluate the efficacy of five major purified salmonella antigens (porins, pili, flagella, outer membrane proteins and heat shock proteins) in modulating T cell‐macrophage interactions which play a central role in resistance to and recovery from infection with several intracellular pathogens, including salmonella. The results showed that the T cells recovered 10 days post‐immunization (D10 T cells) from mice immunized with porins and outer membrane proteins showed maximum proliferation in the presence of macrophages incubated with dead bacteria; however, this response was decreased when T cells were co‐cultured with live Salmonella typhimurium‐infected macrophages. Delayed‐type hypersensitivity responses, as measured by increased footpad thickness at 24 h, though induced effectively by porins, pili and flagella, were completely abrogated when D10 T cells were pre‐incubated with macrophages infected with live bacteria. The phagocytic and bactericidal ability of normal macrophages, when grown in presence of T cell supernatants, was not influenced by the immunizing agents, but T cell supernatants obtained from mice immunized with porins and heat‐shock protein triggered increased bactericidal activity. Further, the expression of the co‐stimulatory molecules ICAM‐1 and B7 increased with increasing bacteria (dead): macrophage ratio, but this expression was down‐regulated upon incubation with live bacteria.
Characterization of human variable domain antibody fragments against the U1 RNA‐associated A protein, selected from a synthetic and a patient‐derived combinatorial V gene library
Authors: de Wildt Ruud M. T. , Finnern Ricarda , Ouwehand Willem H. , Griffiths Andrew D. , van Venrooij Walther J. , Hoet René M. A. 
Published: March 2007

AbstractThis is the first study describing recombinant human antibody fragments directed to the U1 RNA‐associated A protein (U1A). Three anti‐U1A antibody fragments (Fab) were isolated from a semi‐synthetic human Fab library and one anti‐U1A single‐chain variable fragment (scFv) was isolated from a library which was derived from the IgG‐positive splenic lymphocytes of an autoimmune patient. Competition studies with autoantibodies against the U1 small nuclear ribonucleoprotein (snRNP) particle from patients with systemic lupus erythematosus (SLE) and SLE‐overlap syndromes revealed that U1A binding of these antibody fragments can be inhibited by about 40% of the patient sera. All antibody fragments recognized the native U1 snRNP in immunoprecipitation assays. Two of three Fab clones as well as the scFv clone derived from the repertoire of an autoimmune patient use the same heavy chain germ‐line gene DP‐65. Epitope mapping revealed that these three clones appear to recognize an identical epitope domain present on the C‐terminal RNP motif of the U1A protein. The DP‐65 heavy chain gene is used in less than 1% of the B cells in healthy individuals, while three out of four anti‐U1A antibody fragments use this gene. This points to a restricted VH gene usage in the case of U1A, suggesting that the DP‐65 heavy chain has a natural shape complementarity to the U1A protein.