bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell surface marker analysis of mouse thymic dendritic cells
Authors: Ardavin Carlos , Shortman Ken 
Published: March 2007

AbstractCell surface markers of mouse thymic dendritic cells have been studied by flow cytometry after isolation by collagenase digestion, separation of the low‐density cell fraction and differential adherence. The dendritic cell preparation had a purity of > 90%, the contaminating population being essentially composed of thymocytes, macrophages constituting <1%. Dendritic cells displayed high forward and low‐intermediate side angle scatter, and expressed high levels of major histocompatibility complex (MHC) class I and class II molecules, the heat‐stable antigen (HSA), the adhesion molecules Pgp‐1 (CD44), LFA‐1, ICAM‐1 and low levels of Mac‐1 and the leukocyte common antigen CD45. Thymic dendritic cells are negative for the stem cell antigen‐2 (Sca‐2), the B cell‐specific form of CD45 (B220), the mouse macrophage markers Fc receptor and F4/80, and the granulocyte marker Gr‐1. However, although they do not express the T cell markers Thy‐1, CD2, CD3, CD4 and CD5, 20%–30% of dendritic cells are positive for the interleukin 2 receptor α chain (CD25), and about 30% express intermediate levels of CD8.These results are discussed with regard to the functional significance of the expression of CD8 by thymic dendritic cells, and the existence of different dendritic cell subpopulations in the murine thymus.
Impaired post‐transcriptional expression of interleukin‐2 receptor in pokeweed mitogen‐activated T cells
Authors: de la Calle‐Martín Oscar , Alberola‐Ila José , Engel Pablo , Inglés Julia , Fabregat Virginia , Barceló Joan Josep , Lozano Francisco , Gallart Teresa 
Published: March 2007

AbstractThe expression and role of interleukin‐2/interleukin‐2 receptor (IL‐2/IL‐2R) system in the pokeweed mitogen(PWM)‐induced T cell mitogenesis was studied. In the absence of monocytes (Mo), both soluble and Sepharose‐bound PWM fail to induce T cell mitogenesis even when exogenous IL‐2 or IL‐1 or IL‐1+IL‐2 or IL‐4 are also present. In the presence of Mo, PWM stimulation of T lymphocytes (highly depleted of B lymphocytes) induces as much IL‐2 mRNA as phytohemagglutinin (PHA), but results in higher and persistent IL‐2 levels in culture supernatants despite the concomitant T cell mitogenesis, suggesting that PWM‐activated T cells do not utilize the IL‐2 they produce. Confirming this notion, Mo‐dependent PWM‐preactivated T cells, as compared to PHA‐preactivated ones: (a) failed to consume exogenous IL‐2 and their mitogenic response did not increase upon exposure to exogenous IL‐2; (b) exhibited very low numbers of high‐affinity IL‐2R; and (c) showed lower expression of IL‐2R p55 and undetectable expression of IL‐2R p75 on their surface. Moreover, the PWM‐induced T cell mitogenesis was not inhibited by anti‐IL‐2 or CD25 antibodies and only partially (50%–60%) inhibited by cyclosporin A, while these treatments abrogated the PHA‐induced one. PWM‐activated T cells, as compared to the PHA‐activated ones, exhibited as high (p55) or even higher (p75) mRNA expression of both IL‐2R p55 and p75 subunits. The possibility that PWM interferes with IL‐2R subunits once expressed on the T cell surface was excluded. Thus, intracellular PWM‐related events are likely to impair IL‐2R expression post‐transcriptionally. Possible explanations for this effect and its relation with the capacity of PWM to induce T cell‐dependent B cell differentiation are discussed.
The cell‐mediated response to schistosomal antigens at the clonal level: development and characterization of a panel of egg antigen‐specific murine T cell clones
Authors: Chikunguwo Silas M. , Harris Timothy S. , Brodeur Peter H. , Harn Donald A. , Stadecker Miguel J. 
Published: March 2007

AbstractThe cellular basis of the immune response underlying the granulomatous hypersensitivity in experimental murine schistosomiasis caused by Schistosoma mansoni was investigated by examining a panel of 16 egg antigen‐specific T cell clones. The clones were derived from a sensitized T cell line by limiting dilution, and were selected on the basis of their strong responses against schistosomal egg antigens. By cytofluorographic analysis, it was determined that all clones were T helper cells and expressed the CD3+CD4+CD8− phenotype. Lymphokine analysis revealed that some clones secreted either interleukin (IL)‐2 or IL‐4, but a surprisingly large number were double producers. Southern blot analysis verified the clonality of these T cells and indicated that the clones examined included at least five independent clones by the criterion of T cell receptor β gene rearrangements. Despite their diversity, the clones responded strongly, and virtually exclusively, to egg antigen components with isoelectric points in the limited range of 4.7 to 5.2. The relevant antigenic egg molecules were shown to require processing by accessory cells for presentation to, and stimulation of, the T cell clones.
Inhibition of superantigen recognition by peptides of the variable region of the T cell receptor β chain
Authors: Macneil Donna , Fraga Ester , Singh Bhagirath 
Published: March 2007

AbstractT cells bearing certain variable (V) regions of the T cell receptor (TcR), including Vβ3, Vβ6, Vβ8.1 and Vβ9, are stimulated by one or more forms of the endogenous superantigen, mouse lymphocyte stimulatory (Mls) locus, encoded by the mouse mammary tumor virus, in the context of a non‐polymorphic region of the class II molecules of the major histocompatibility complex (MHC). To identify putative sites of interaction of TcR‐Vβ region and Mls‐1a, we examined the effect of peptides derived from the protein sequence of Vβ6 on recognition of Mls‐1a by T cell hybridomas and show that three peptides corresponding to amino acid positions 1 to 20, 48 to 75, and 58 to 75 of the Vβ6 peptide sequence interfere with the activation of several Vβ6+ hybridomas by Mls‐1a‐bearing spleen cells, but not with that of a Vβ8+ hybridoma. The Mls‐reactive hybridomas are specific for a synthetic peptide poly‐18, poly EYK(EYA)5 and its peptide (EYA)5, in the context of I‐Ad. This peptide does not require processing and the peptides 1–20, 48–75, and 58–75 do not inhibit recognition of (EYA)5 by the same Vβ6+ T cell hybridomas. The two sequences 1–20 and 58–75 are proposed to lie outside the putative binding domain of processed antigen, indicating that recognition by TcR of Mls‐1a is different from the classical MHC‐restricted recognition of processed antigen. These results suggest that the recognition of superantigen/class II MHC by T cells can be inhibited by peptides related to the site of interaction of the TcR, suggesting that such peptides could have possible regulatory effects on the induction and regulation of immune responses.
Opposing effects of tumor necrosis factor‐α and nerve growth factor upon leukotriene C4 production by human eosinophils triggered with N‐formyl‐methionyl‐leucyl‐phenylalanine
Authors: Takafuji Shigeru , Bischoff Stephan C. , de Weck Alain L. , Dahinden Clemens A. 
Published: March 2007

AbstractTumor necrosis factor (TNF) as well as the hematopoietic growth factors interleukin‐3, interleukin‐5, and granulocyte‐macrophage colony‐stimulating factor affect several eosinophil functions. We previously reported (J. Exp. Med. 1989. 170: 467; 1990. 172: 1577) that the hematopoietic growth factors also potentiate leukotriene C4 (LTC4) formation by eosinophils as well as basophils stimulated with soluble chemotactic peptides such as N‐formyl‐methionyl‐leucyl‐phenylalanine (FMLP), but whether TNF also modulates lipid mediator generation in normodense eosinophils triggered with FMLP is unkonwn. Here we show that a short preincubation (10 min) of human eosinophils purified from healthy donors with low concentrations of TNF (5‐150 pM) strongly enhances LTC4 formation in response to FMLP. However, basophil mediator release is not affected by TNF preincubation. Nerve growth factor (NGF), the receptor of which is structurally related to the TNF receptors, tended to suppress lipid mediator synthesis in eosinophils, in contrast to its profound potentiating capacity on basophil mediator release. Thus, the present study demonstrates a first difference in susceptibility of eosinophils and basophils towards cytokines, indicating that TNF and NGF may regulate the relative importance of effector functions of these otherwise closely related cell types.
Somatically mutated IgG anti‐DNA antibody clonally related to germ‐line encoded IgM anti‐DNA antibody
Authors: Taki Shinsuke , Hirose Sachiko , Kinoshita Kohji , Nishimura Hiroyuki , Shimamura Toshiro , Hamuro Junji , Shirai Toshikazu 
Published: March 2007

AbstractAmong 15 anti‐DNA antibody‐producing hybridomas derived from a single NZB × NZW F1 mouse, an IgM and an IgG were shown to use the same VH gene of the Q52 family. Using a combination of two primers both consisting of a mixture of oligonucleotides (one complementary to the 5′ end of VH segment and one to the 3′ end of VH segment of Q52 family) we determined the sequences of several members of germ‐line VH genes in the Q52 family derived from NZB and NZW strains. Comparison of the sequences with those of cloned VH cDNA obtained from the hybridomas revealed that the VH sequence of the IgM anti‐DNA antibody was identical to that of a cloned NZW germ‐line VH gene, except for the priming sites. In contrast, the VH sequence of the IgG counterpart contained somatically mutated nucleotides. Because the IgG anti‐DNA antibody showed a higher DNA binding activity than did the IgM antibody, we conclude that these changes in nucleotide sequences were induced and selected through an antigen‐driven mechanism as is the case in a normal immune response. It is tempting to speculate that the germ‐line encoded, low‐affinity IgM autoantibody undergoes somatic mutations and isotype switching, resulting in generation of pathogenic, high‐affinity autoantibodies in autoimmune diseases.
The stromal cell line S17 supports the growth of lipopolysaccharide‐stimulated CBA/N spleen cell colonies in vitro
Authors: Narendran Arumugavadivel , Cumano Ana , Dorshkind Kenneth , Paige Christopher J. 
Published: March 2007

AbstractThe expression of an X‐linked defect in the CBA/N strain of mice has been found to result in a number of immune abnormalities. These include low responsiveness to antigens and a greatly reduced ability to respond to many of the common B cell mitogens. An in vitro manifestation of this condition is the virtual inability of CBA/N B cells to form colonies in lipopolysaccharide (LPS)‐containing semisolid agar cultures. In this report we show evidence that the colony‐forming ability of CBA/N spleen cells can be effectively restored by the bone marrow stromalderived cell line S17. Spleen cells from 4–5‐week‐old homozygous CBA/N female mice were grown in double‐layer agar cultures containing S17 feeder layers. Control cultures contained the fibroblast‐like cell line 95.17 or were treated with medium alone. It was found that at an input cell concentration of 104 cells per plate, CBA/N colony formation was increased from a frequency of approximately 1 in 5000 to 1 in 50 total splenic cells. Studies with purified surface immunoglobulin‐positive cells indicate the direct involvement of S17 in this process. The CBA/N colonies formed were dependent on the presence of a mitogen (LPS) and secreted detectable amounts of IgM. Major implications of these findings and the application of this assay system to study the CBA/N defect have been discussed.
Interleukin‐7 expression during mouse thymus development
Authors: Wiles Michael V. , Ruiz Patricia , Imhof Beat A. 
Published: March 2007

AbstractWe have monitored the expression of interleukin‐7 (IL‐7) in the developing embryonic mouse thymus by a combination of quantitative polymerase chain reaction (PCR) and immunofluorescence microscopy. A strong specific signal for IL‐7 mRNA was detected by day 12 in the developing fetal thymus. IL‐7 mRNA was found to be maximally expressed on day 15, and then decreased over the next 5 days. Immunofluorescence staining of fetal thymus sections using an anti‐IL‐7 antibody confirmed these PCR data. IL‐7 protein expression was first detected at day 13 of development. At 14 days the intensity of the staining increased by a factor of three and stayed at this level over the next 4 days. The same anti‐IL‐7 antibody used for immunofluorescence, blocked the proliferation of fetal thymocytes in organotypic cultures. In addition, we detected mRNA coding for IL‐2 and SCF (also known as the steel factor or KL) in embryonic thymocytes. The implications of these findings for early thymocyte growth are discussed.
A lymphocyte differentiation and activation antigen, CZ‐1, that distinguishes between CD8+ and unstimulated CD4+ T lymphocytes
Authors: Vargas‐Cortes Mauricio , O'Donnell Carey L. , Appel Michael C. , Maciaszek Joseph W. , Yurkunas Kate S. , Welsh Raymond M. 
Published: March 2007

AbstractWe report the generation and cellular reactivity of a novel rat IgM monoclonal antibody (mAb), CZ‐1, made against mouse natural killer (NK) cells activated in vivo. mAb CZ‐1 recognizes a molecule whose properties are consistent with that of a trypsin‐sensitive, non‐phosphatidyl inositol‐linked sialoglycoprotein. The expression of the antigen recognized by mAb CZ‐1 is restricted mostly to cells of the lymphoid lineage. The antigen is expressed on 10%–25% of bone marrow cells and 3%–5% of thymocytes. Analysis of thymocyte subpopulations indicates expression of the CZ‐1 antigen on 100% of the NK1.1+, 27% of the CD4−CD8−, 1.1% of the CD4+CD8+, 1.1% of the CD4+CD8−, and 33% of the CD4−CD8+ cells. In the spleen, the CZ‐1 antigen is expressed on B lymphocytes, NK cells, and virtually all CD8+ T lymphocytes. Most unstimulated CD4+ splenic T lymphocytes, monocytes and polymorphonuclear cells, with the notable exception of basophils, do not react with mAb CZ‐1. CD4+ T cells activated in vivo by virus infection or in vitro by anti‐CD3 and interleukin‐2 express the CZ‐1 antigen. These results indicate that mAb CZ‐1 identifies a novel inducible lymphocyte activation/differentiation antigen that distinguishes between thymic and unstimulated splenic CD4+ and CD8+ T lymphocytes. This mAb will be a useful tool in the identification of lymphocyte subpopulations and in the study of the ontogeny and activation of these cells.
Differential expression of granzyme A and granzyme B proteases and their secretion by fresh rat natural killer cells (NK) and lymphokine‐activated killer cells with NK phenotype (LAK‐NK)
Authors: Velotti Francesca , Palmieri Gabriella , D'Ambrosio Daniele , Piccoli Mario , Frati Luigi , Santoni Angela 
Published: March 2007

AbstractGranzymes A—G are a family of serine proteases localized in the cytoplasmic granules of cytotoxic T lymphocytes (Masson, D. et al. Cell 1987. 49: 679) and granzyme A is secreted by T lymphocytes in response to antigenic stimulation. Granzyme A is also expressed by natural killer (NK) and lymphokine‐activated killer (LAK) cells. Here we show that fresh rat NK cells constitutively express granzyme B and that granzyme A and granzyme B are differentially regulated in unstimulated NK cells vs. LAK cells with NK phenotype (LAK‐NK cells). We also show that both granzymes A and B are secreted in a calcium‐dependent manner, by NK and LAK‐NK cells in response to stimuli which trigger NK cell functions.
Increased numbers of T cells recognizing multiple myelin basic protein epitopes in multiple sclerosis
Authors: Olsson Tomas , Sun Jiabin , Hillert Jan , Höjeberg Bo , Ekre Hans‐Peter , Andersson Gudrun , Olerup Olle , Link Hans 
Published: March 2007

AbstractMyelin basic protein (MBP)‐autoreactive T cells have a crucial pathogenetic role in experimental allergic encephalomyelitis (EAE) and certain MBP epitopes may be immunodominantly recognized. The heterogeneity and quantity of the T cell response to different epitopes of MBP in multiple sclerosis (MS) and non‐MS controls is not so clearly defined. We now study T cell reactivity to six different peptides of MBP in MS compared to controls in short‐term cultures of blood mononuclear cells by measuring numbers of T cells that secrete interferon‐γ in response to antigen. In comparison with controls, MS patients showed dramatically increased numbers of MBP peptide‐reactive T cells with mean values varying between 10.4 and 22.5 per 105 blood mononuclear cells. Among those MBP peptides examined (amino acid 1–20, 63–88, 89–101, 96–118, 110–128 and 148–165), no single peptide is preferentially recognized. Neither is any preferential response apparent after subdivision of the MS patients according to their HLA‐DR genotype. Our findings suggest that a quantitative increase of a broad repertoire of myelin‐autoreactive T cells with capacity to secrete IFN‐γ can be important for the pathogenesis of MS.
Membranes of activated CD4+ T cells expressing T cell receptor (TcR) αβ or TcR γδ induce IgE synthesis by human B cells in the presence of interleukin‐4
Authors: Gascan Hugues , Aversa Gregorio G. , Gauchat Jean‐Françlois , Van Vlasselaer Peter , Roncarolo Maria‐Grazia , Yssel Hans , Kehry Marilyn , Spits Hergen , De Vries Jan E. 
Published: March 2007

AbstractIn the present study it is demonstrated that human B cells can be induced to switch to IgE production following a contact‐mediated signal provided by activated T cell receptor (TcR) γδ+, CD4+ and TcR αβ+, CD4+ T cell clones and interleukin (IL)‐4. The signal provided by these T cell clones was antigen nonspecific, indicating that the TcR αβ/CD3 or TcR γδ/CD3 complexes were not involved in these T‐B cell interactions. Activated TcR αβ+, CD8+, and TcR γδ+, CD4−CD8−, or resting CD4+ T cell clones were ineffective. Intact TcR αβ+ or TcR γδ+, CD4+ T cell clones could be replaced by plasma membrane‐enriched fractions isolated from these activated CD4+ T cell clones. In contrast, membranes isolated from resting TcR αβ+, CD4+, TcR γδ+, CD4+ T cell clones or an Epstein‐Barr virus (EBV)‐transformed B cell line (EBV‐LCL) failed to provide the costimulatory signal that, in addition to IL‐4, is required for induction of IgE synthesis. As described for intact CD4+ T cells, CD4+ T cell membranes induced purified surface IgM+ B cells to switch to IgG4‐ and IgE‐ but not to IgA‐producing cells, excluding the possibility of a preferential outgrowth of IgG4‐ and IgE‐committed B cells. The membrane activity was inhibited by protease or heat treatment. Induction of IgE synthesis by B cells co‐cultured with both TcR αβ+, CD4+ and TcR γδ+, CD4+ T cell clones and membrane preparations of these cells was blocked by anti‐class II major histocompatibility complex (MHC) monoclonal antibodies (mAb), whereas various anti‐CD4 mAb had differential blocking effects. Murine L cells, or EBV‐LCL transfected with CD4 could not replace CD4+ T cell clones. These results indicate that, although CD4 and class II MHC antigens are required for productive CD4+ T cell clone‐B cell interactions, an additional signal, provided by a membrane associated (glyco)protein that is induced by activation of both TcR αβ and TcR γδ, CD4+ T cells, is needed for induction of IgE production in the presence of IL‐4.
Interleukin‐1 up‐regulates transcription of its own receptor in a human fibroblast cell line TIG‐1: role of endogenous PGE2 and cAMP
Authors: Takii Takemasa , Akahoshi Tohru , Kato Koichi , Hayashi Hidetoshi , Marunouchi Tohru , Onozaki Kikuo 
Published: March 2007

AbstractThe regulation of interleukin‐1 receptor (IL‐1R) mRNA expression by IL‐1 in a human lung fibroblast cell line (TIG‐1) was investigated. After 2 h of stimulation with human recombinant IL‐1α or IL‐1β, the levels of T cell/fibroblast‐type IL‐1R mRNA increased, and the elevation was sustained for at least 72 h. IL‐1 also stimulated synthesis of prostaglandin E2 (PGE2) and secondary cAMP accumulation. Exogenously added PGE2 increased the levels of both IL‐1R mRNA and intracellular cAMP. Forskolin, cholera toxin and 8‐Bromo adenosine (8‐Br‐cAMP) all increased IL‐1R mRNA levels. Indomethacin blocked IL‐1 stimulation of IL‐1R mRNA expression, PGE2 production and cAMP. 125I‐labeled IL‐1α‐binding studies showed that this cell line expresses 2.6 × 104 IL‐1R per cell with a Kd of 5.1 × 10−10 M. After treatment of the cells with IL‐1, the level of IL‐1R increased over that of control cells. PGE2 also increased IL‐1R without alteration in its affinity. Cross‐linking experiments indicate that this cell line expresses the 80‐kDa receptor molecule before and after treatment with PGE2; the molecular mass corresponds to the T cell/fibroblast type IIL‐1R. These results indicate that IL‐1 does not directly stimulate expression of IL‐1R mRNA or cell surface IL‐1R, but only indirectly by stimulation of endogenous PGE2.
Origin of CD5+ B cells and natural IgM‐secreting cells: reconstitution potential of adult bone marrow, spleen and peritoneal cells
Authors: Thomas‐Vaslin Véronique , Coutinho Antonio , Huetz François 
Published: March 2007

AbstractThe bulk of natural IgM secretion is currently attributed to peritoneal CD5+ B cells and their progeny, believed to be independent of adult bone marrow precursors. We have compared the capacity of peritoneal or splenic cells from normal adult mice to generate serum IgM after transfer into allotype‐congenic, irradiated and bone marrow‐protected mice. Recipients of either cell population produced donor‐allotype IgM‐secreting cells in the spleen, and had donor‐derived serum IgM. In both cases as well, recipient IgM secretion recovered to control levels. Since the spleen cell‐derived natural IgM production could result from expansion of CD5+ B cells present in the inoculum, we next investigated the ability of Ig− bone marrow (BM) cells (Ig− BM) to reconstitute natural IgM secretion in irradiated mice. This cell population was most efficient in reconstituting donor‐derived IgM secretion.The origin and phenotype (IgM, CD5) of B cells present in spleen and peritoneum of recipient mice were also analyzed. In agreement with the high level of donor IgM‐secreting cells, transfers of splenic and Ig− BM cells fully reconstitute donor B cells in spleen and peritoneum and inhibit reconstitution from host origin. In contrast, donor peritoneal cells reconstitute B cells very poorly in spleen and allow for reconstitution by host cells. Furthermore, Ig− BM cells as well as splenic or peritoneal donor cells, all reconstitute CD5+ B cells in the peritoneum of recipient mice. Interestingly, the fraction of IgM+ cells of each allotype that differentiate to IgM secretion varies widely, but normal levels of IgM are established even when the number of donor B cells present in the animal is very limited.