bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tolerance induction by clonal deletion of CD4+8+ thymocytes in vitro does not require dedicated antigen‐presenting cells
Authors: Pircher Hanspeter , Brduscha Karin , Steinhoff Ulrich , Kasai Michiyuki , Mizuochi Toshiaki , Zinkernagel Rolf M. , Hengartner Hans , Kyewski Bruno , Müller Klaus‐Peter 
Published: March 2007

AbstractThe cellular requirements of T cell tolerance induction in the thymus by clonal deletion was investigated by using an in vitro assay: thymocytes from mice expressing a transgenic TcR specific for lymphocytic choriomeningitis virus (LCMV) and H‐2Db were co‐cultured with various H‐2b cell types as antigen‐presenting cells in the presence of the antigenic LCMV peptide. The results revealed that all cell lines examined including embryonic and transformed fibroblasts, melanoma cells, cortical thymic epithelial cells, lymphomas and neuronal cells induced an antigen dose‐dependent deletion of CD4+8+ thymocytes. Similarly, highly enriched accessory cell populations from thymus and spleen (macrophages, dendritic and cortical epithelial cells, i.e. thymic nurse cells) could induce antigen‐specific depletion of immature CD4+8+ thymocytes. Depending on the cell type examined micromolar to picomolar concentration of LCMV peptide were required to induce deletion. The effectiveness of deletion by the different cell types did not correlate with their major histocompatibility class I expression level; it was, however, influenced by the presence of ICAM‐1 adhesion molecules.
Dissociation of natural killer and lymphocyte‐activated killer cell lytic activities in human CD3− large granular lymphocytes
Authors: Clément Marie‐Véronique , Legros‐Maida Sabine , Soulie Annie , Jacqueline Guillet  , Sasportes Marilyne 
Published: March 2007

AbstractCD3− large granular lymphocytes (LGL) are known to display natural killer cell (NK) activity without prior sensitization or restriction by major histocompatibility antigens. Upon short‐term exposure to interleukin‐2, NK cells were shown to acquire lymphocyte‐activated killer cell (LAK) activity. The aim of this study was to analyze the characteristics of these lytic activities. Our data indicated that both NK and LAK activities were Ca2+ dependent; however, they could be dissociated by a Ca2+ channel blocker or a Ca2+ channel competitor agent. Moreover, NK activity was associated with granule exocytosis of lytic proteins spontaneously present in CD3− LGL, the most likely candidate being the pore‐forming protein perforin. By contrast, LAK activity was found to be dependent on de novo protein synthesis and distinct from granule exocytosis. Our results strongly suggest that NK and LAK activities could be defined as two distinct pathways involving different lytic mediators.
Treatment with anti‐CR3 antibodies ED7 and ED8 suppresses experimental allergic encephalomyelitis in Lewis rats
Authors: Huitinga Inge , Damoiseaux Jan G. M. C. , Döpp Ed A. , Dijkstra Christine D. 
Published: March 2007

AbstractExperimental allergic encephalomyelitis (E AE) is an inflammatory disease of the central nervous system (CNS). Among the leukocytes which infiltrate the CNS during EAE, numerous macrophages are present. These macrophages are thought to play a crucial role in the generation of tissue damage and attendant neurological deficits. The mechanism by which the macrophages migrate across the blood‐brain barrier is not yet clear. Membrane proteins involved in macrophage adherence to the endothelium include the CD11b/CD18 integrin, also known as the type 3 complement receptor (CR3). In this study we show that two monoclonal antibodies (mAb) ED7 and ED8 are directed against rat CR3. In addition, these mAb reduce recruitment of myelomonocytic cells towards thioglycollate induced peritonitis by 15‐33%. This indicates that both ED7 and ED8 interfere with an epitope on CR3, which is involved in recruitment of phagocytes towards inflammatory lesions. Intravenous injection of ED7 and ED8 suppressed clinical signs of EAE. MRC OX‐42, which also recognizes CR3, did not reduce thioglycollate‐induced phagocyte recruitment into the peritoneum, and had no effect on EAE. These findings suggest that CR3 plays a role in the recruitment of macrophages towards the inflamed CNS of EAE animals, and confirm the role of macrophages in the generation of clinical signs of EAE. Involvement of CR3 in other phagocyte immune functions during EAE is discussed.
The murine T cell line CT6 provides a novel bioassay for interleukin‐7
Authors: Willcocks Joanie L. , Hales Anne , Page Theresa H. , Foxwell Brian M. J. 
Published: March 2007

AbstractLike interleukin (IL)−2 and IL‐4, IL‐7 can act as a growth factor for activated T lymphocytes. Upon screening a panel of growth factor‐dependent T cell lines, we found that only the cell line CT6 responded to IL‐7, indeed as vigorously as to IL‐2. Obviously, these findings challenge the validity of previous results on IL‐2 production obtained using the CT6 cell line. However, they also demonstrate a novel and sensitive system for the bioassay of IL‐7. The ability of the surveyed T cell lines to proliferate to IL‐7 corresponded with the expression of IL‐7 receptors (IL‐7R) on the cell surface. The murine IL‐7R on CT6 was shown to bind IL‐7 with dual affinity and was visualized as an affinity cross‐linked complex of 93 kDa. This IL‐7R appears similar to that seen on murine splenic T cells and on 70Z/3, the pre‐B cell line from which the murine IL‐7R was cloned.
Chicken B cells adhere to the CS‐1 site of fibronectin throughout their bursal and postbursal development
Authors: Palojoki Eeva , Toivanen Paavo , Jalkanen Sirpa 
Published: March 2007

AbstractIn chickens, the pre‐B cell development takes place in a specialized organ, the bursa of Fabricius. In this study, we show that fibronectin can be detected in the bursa at least from the day 15 of embryonic incubation up to 10 weeks of age after which the bursa starts to involute. During the embryonic incubation, fibronectin localizes mainly in the areas between the follicles and later on also in the border zone between the cortical and medullary parts of the lymphoid follicles. By adhesion studies with synthetic peptides we show that immature bursal B cells bind in a dose‐dependent manner to the CS‐1 site of the type III connecting segment at the carboxy‐terminal end of fibronectin throughout their bursal development. Postbursal B cells from chicken spleen also display a similar preference of binding to the CS‐1 site of fibronectin, whereas peripheral blood B lymphocytes bind to the 40‐kDa fragment of fibronectin, but do not adhere as strongly to the CS‐1 site. Instead, they recognize to some extent also the heparin‐binding YEKPGSPPREVVPRPRPGV peptide. The adhesion of the bursal B cells to the CS‐1 site can partially be blocked by preincubation of cells with a synthetic CS‐1 peptide and also by preincubation with a monoclonal anti‐fibronectin receptor antibody. In contrast, the RGD motif present in several adhesion‐associated stromal molecules did not promote any adherence of bursal lymphocytes. The bursal B cells which adhere to the fibronectin molecule in vitro form only a small fraction of the total number of B cells present in the bursa as only less than 4% of the cells remained bound to the surface coated with fibronectin in the adhesion studies. In conclusion, these results suggest that fibronectin may be involved in the differentiation of pre‐B cells in the bursa of Fabricius and also in the adherence of postbursal B cells in the spleen.
Soluble T cell receptor‐like properties of an HLA‐B35‐specific monoclonal antibody (TÜ165)
Authors: Uchańska‐Ziegler Barbara , Nößner Elfriede , Schenk Andrea , Ziegler Andreas , Schendel Dolores J. 
Published: March 2007

AbstractA mouse monoclonal antibody of IgM class (TÜ165) was produced using Epstein‐Barr virus (EBV)‐infected mutant cells derived from the human BJAB‐B95.8.6 cell line as immunogen. Binding studies with several HLA deletion mutant cell lines indicated that TÜ165 recognized the HLA‐B35 molecule. In a panel of 89 EBV‐transformed lymphoblastoid cell lines, all HLA‐B35+ cells (n = 24) reacted with TÜ165 while all but two HLA‐B35− lines (n = 65) were unreactive (r = 0.95). Surprisingly, peripheral blood lymphocytes of HLA‐B35+ donors were unreactive; however, strong enhancement of TÜ165 recognition was observed with B cells of one of these individuals after transformation with EBV (B95.8 strain). Transfection of both HLA‐B35 and human ß‐microglobulin genomic DNA into mouse P815 cells led to high expression of HLA‐B molecules; yet, expression of the TÜ165 epitope was not observed. Furthermore, the EBV‐negative cell line BJAB as well as the EBV‐infected (P3HR1 strain) line BJAB‐HR1K were only weakly reactive, whereas the BJAB‐B95.8 cell line was strongly positive. These results indicate that EBV‐encoded or ‐controlled peptide(s) must be bound by HLA‐B35 antigens to create the epitope which allows efficient binding of TÜ165.
CD 69 expression during selection and maturation of CD4+8+ thymocytes
Authors: Swat Wojciech , Dessing Mark , Boehmer Harald Von , Kisielow Pawel 
Published: March 2007

AbstractWe have analyzed the inducibility of protein kinase C (PKC)‐dependent expression of CD 69 molecules in T cell receptor (TCR) transgenic thymocytes developing in the presence or absence of selecting, class I major histocompatibility complex (MHC) molecules. Small CD4+8+ thymocytes developing in the absence of selecting MHC molecules could not be induced to express CD 69 by TCR cross‐linking even after spontaneous in vitro up‐regulation of their TCR level which resulted in enhanced Ca++ flux. In contrast, a small proportion of CD4+8+TCRlow and most TCRhigh (CD4+8+ and CD4+8+) thymocytes developing in the presence of selecting MHC ligands could be induced to express CD 69 upon TCR cross‐linking. Unlike the anti‐TCR antibody, phorbol 12‐myristate 13‐acetate ‐ a direct activator of PKC ‐ induced the expression of CD 69 on all thymocytes. These results suggest that positive selection of CD4+8+ thymocytes results in coupling of TCR‐mediated signals to the CD 69 expression pathway. In vitro analysis of thymocytes before and after positive selection suggests that (1) positive selection does not immediately result in resistance to deletion and (2) that sustained TCR ligation is needed to promote maturation of positively selected CD4+8+ thymocytes resulting in gradual loss of the sensitivity to deletion and acquisition of the ability to proliferate in response to TCR‐mediated signals.
Thymic and peripheral apoptosis of antigen‐specific T cells might cooperate in establishing self tolerance
Authors: D'Adamio Luciano , Awad Katherine M. , Reinherz Ellis L. 
Published: March 2007

AbstractAside from CD4+CD8+ double‐positive (DP) thymocytes, the subpopulations of T lineage cells affected by negative selection are unknown. To address whether this process occurs in more mature cell types, we have compared the responses of purified single‐positive (SP) murine thymocytes and peripheral T cells to the superantigen staphylococcal enterotoxin B (SEB) utilizing as antigen‐presenting cells (APC) a fibroblast cell line expressing transfected I‐Ek class II molecules. Whereas ∽ 70% of SEB‐reactive SP thymocytes, either CD4+ or CD8+, undergo programmed cell death (apoptosis) and, therefore, negative selection, CD4+ and CD8+ antigen‐specific peripheral T cells are predominantly activated and proliferate to APC+SEB. Thus, mature thymocytes and peripheral T cells, with identical patterns and levels of expression of CD4, CD8 and T cell receptor (TCR), are programmed to elicit different responses followingTCR stimulation. Unexpectedly, however activation of peripheral T cells was preceded by deletion of a large fraction of Vβ8+ T lymphocytes (SEB specific). This surprising phenomenon was also observed in in vivo studies: in fact, administration of SEB to adult mice resulted in depletion of the majority of antigen‐specific T cells from the peripheral lymphoid tissues analyzed (lymph nodes and spleen). This depletion is the consequence of deletion as indicated by program cell death of Vβ8+ T cells and is followed by proliferation of the remaining SEB‐reactive T cells. Clonal elimination of peripheral T cells may represent a mechanism by which tolerance to self antigens never expressed in and/or exported to the thymus is achieved.
Role of environmental antigens in B cell proliferation in the bursa of Fabricius at neonatal stage
Authors: Ekino Shigeo 
Published: March 2007

AbstractEffect of environmental antigens on S phase entry rate of bursa cells was studied by utilizing in vivo incorporation of bromodeoxyuridine (BrdUrd). S phase entry rate of bursa cells in chick embryo was determined to be 6.4 %/h, this rate increased to 10.0 %/h at neonatal stage and decreased to 6.4 %/h 6 weeks after hatching. Evidence is presented that isolation of the bursa from the gut before hatching suppressed S phase entry rate of bursa cells after hatching, whereas S phase entry rates of thymocytes were not affected. On tissue sections, a decrease of BrdUrd+ cells was observed in medullary areas of the isolated bursa. It is proposed that in situ stimulation of bursa cells by environmental antigens to the bursa accelerates S phase entry rates, and that medullary areas are the major sites for antigen‐driven B cell proliferation after hatching.
Effects of intrathymic injection of organ‐specific autoantigens, parietal cells, at the neonatal stage on autoreactive effector and suppressor T cell precursors
Authors: Murakami Kyoko , Maruyama Hidenori , Nishio Akiyoshi , Kuribayashi Kagemasa , Inaba Muneo , Inaba Kayo , Hosono Masamichi , Shinagawa Kunihiro , Sakai Masahiko , Masuda Tohru 
Published: March 2007

AbstractThymectomy on day 3 after birth (3d‐Tx) induces autoimmune gastritis (AIG) in 81%, and oophoritis (AIO) in 25% of BALB/c mice at the age of 2 to 3 months. Intrathymic, but not intraperitoneal injection of syngeneic parietal cells into sex‐matched BALB/c mice within 24 h of birth resulted in almost complete prevention of the development of AIG in these mice in which 3d‐Tx was performed. The prevention induced was parietal cell specific, since the development of AIO was not inhibited in female mice. Moreover, the injection of BALB/c liver cells, Mls‐matched (BALB/c) and ‐disparate (DBA/2) B blasts which resulted in Vβ6 T cell deletion, as well as the injection of staphylococcal enterotoxin B failed to prevent the diseases. These findings suggested that recognition of an autoantigen in the thymus is necessary for the induction of tolerance, and that involvement of Mls‐1 antigens in the pathogenesis of AIG, as has been suggested previously (Schwartz, R. H., Cell 1989. 57: 1073), was unlikely.T cells that suppress the development of organ‐specific autoimmune diseases in 3d‐Tx mice seem to maintain the unresponsiveness of autoreactive T cells at the periphery in normal mice. In agreement with our previous observations, we found that intraperitoneal (i.p.) injection of spleen cells from 3‐month‐old normal mice into 3d‐Tx mice on day 10 after birth prevented the development of AIG, whereas spleen cells from age‐matched AIG+ (mice with AIG) or AIG− (mice without AIG) 3d‐Tx mice failed to do this. This implies that the suppressor cells probably affect the differentiation of effector‐precursor to effector. In fact, these suppressor cells did not inhibit the adoptive transfer of AIG to nu/nu BALB/c mice by spleen cells from 3d‐Tx mice manifesting AIG. By negative selection using monoclonal antibody and complement, it was confirmed that the phenotype of the suppressor cell was CD4. In contrast to 3d‐Tx, 10d‐Tx did not induce AIG, indicating the peripheralization of the suppressor cell by that time. On the other hand, intrathymic injection of parietal cells immediately after birth did not affect suppressor cell generation, implying that some T cells, including suppressor cells, escape thymus selection. We postulate that these cells correspond to the precursors of the autoreactive effector T cells and suppressor T cells that are present in normal mice.
Clonal deletion of thymic mature T cells induced by staphylococcal enterotoxin B in murine fetal thymus organ culture
Authors: Aiba Yuichi , Mazda Osam , Matsuzaki Yumi , Nakauchi Hiromitsu , Muramatsu Shigeru , Katsura Yoshimoto 
Published: March 2007

AbstractThe present study aims at investigating the intrathymic maturational stage of T cells at which clonal deletion can be induced. Staphylococcal enterotoxin B (SEB) was added to organ cultures of murine fetal thymus lobes at various time points of culture, and Vβ8‐expressing cells were assayed on day 14. Vβ8 low‐expressing (Vβ8′°) cells were reduced to 40‐60 % of the control receiving no SEB, though the reduction was ambiguous when SEB was given on day 13. In marked contrast, Vβ8 high‐expressing (Vβ8hi) cells were virtually completely deleted in all groups including the group given SEB on day 13. Most of the Vβ8hl cells that were deleted by 24 h of treatment with SEB were shown to be of the CD4+8 mature phenotype, though CD4−8+Vβ8hi cells were also deleted. It was further shown that the thymic Vβ8hi CD4+8− cells recovered from organs cultured for 14 days without SEB responded to immobilized anti‐Vβ8 monoclonal antibody, indicating that Vβ8hi cells, which were highly sensitive to clonal deletion, were functionally competent mature T cells. These results strongly suggest that the thymus is capable of eliminating all T cells recognizing antigen present in the thymus regardless of the maturational stage of T cells.
Large, detergent‐resistant complexes containing murine antigens Thy‐1 and Ly‐6 and protein tyrosine kinase p56lck
Authors: Bohuslav Jan , Cinek Tomáš , Hořejší Václav 
Published: March 2007

AbstractA number of human and mouse leukocyte surface (glyco)proteins anchored in a membrane via glycosylphosphatidylinositol (GPI) moiety have been previously shown to be noncovalently associated with protein tyrosine kinases (Science 1991. 254: 1016; J Biol. Chem. 1992. 267:12317). Here we show that two murine antigens of this group, Thy‐1 and Ly‐6, implicated in the activation of the T cells, are associated with each other, with the kinase p56lck and with several of potential kinase substrates in very large, detergent‐resistant complexes, the size of which is between 50 and 200 nm, as determined by ultrafiltration and gel chromatography. Experiments on simultaneous solubilization of mixed human and mouse cells rule out that the observed complexes are artifacts induced by the detergent. Complexes of similar composition and properties were obtained when either detergents Brij‐58, Nonidet‐P40 or 3‐[(3‐cholamidopropyl)‐dimethylammonio]‐1‐propane‐sulfonate (Chaps) were used for solubilization of the cells, while octylglucoside at least partially dissociated them. These “GPI‐complexes” may be essential for the well‐known signal‐transducing capacity of Thy‐1 and Ly‐6.
The human immunoglobulin VH7 gene family consists of a small, polymorphic group of six to eight gene segments dispersed throughout the VH locus
Authors: van Dijk Ko Willems , Mortari Frank , Kirkham Perry M. , Schroeder Harry W. , Milner Eric C. B. 
Published: March 2007

AbstractIn this report we describe the analysis and mapping of members of the human immunoglobulin VH7 gene family. VH7 and VH1 gene segments are closely related, with individual gene segments sharing between 78% and 82% sequence identity. Divergence from VH1 gene sequence occurs as an abrupt event at the boundary between framework region (FR) 2 and complementarity‐determining region (CDR) 2 and continues through a major portion of FR 3. We used polymerase chain reaction amplification to create a 162‐base pair probe spanning the family‐specific region of CDR 2 and FR 3 that proved suitable for standard Southern analysis of genomic DNA. The VH7 gene family was found to be a small but discrete VH gene family consisting of five to eight germ‐line elements, of which at least three are polymorphic. Four different VH7 gene segments were cloned from the germ line of a single individual, and assigned to specific restriction fragments by sequence‐specific hybridization. Two of the four VH7 elements were pseudogenes. The pattern of sequence variation in these and other known pseudogenes suggests that these nonfunctional elements may play a role in the evolution of novel VH families. A combination of one and two‐dimensional pulsed field gel electrophoresis was employed to map the chromosomal location of all of these VH7 elements. Individual VH7 gene segments were found to be dispersed over a region of at least 940 kb of DNA, and interspersed with members from other VH gene families. The polymorphism of the VH7 gene segments and their scattered location throughout the VH locus makes them potentially useful markers for mapping and linkage studies.
The effect of anchor residue modifications on the stability of major histocompatibility complex class I‐peptide interactions
Authors: Neefjes Jacques J. , And John Dierx , Ploegh Hidde L. 
Published: March 2007

AbstractAnchor residues in peptides determine the specificity of binding to major histocompatibility complex class I molecules through interactions of their side chains with pockets in the peptide‐binding groove. We have compared the kinetics of association of a Sendai virus nucleoprotein‐derived peptide (FAPGNYPAL, termed SV9) with H‐2Kb class I molecules, and the same peptide iodinated on the anchor residue tyrosine (125I‐SV9). Even though the association rates were too rapid for direct measurements, competition studies indicated that they were similar for SV9 and 125I‐SV9. To measure the binding of non‐radioactive SV9 directly, SV9 was tritiated (3H‐SV9). 3H‐SV9 remained stably associated with H‐2Kb molecules, whereas 125I‐SV9 dissociated in a temperature‐dependent fashion. Thus, modifications on anchor residues do not necessarilly have to affect the specificity and association kinetics of peptide binding to class I molecules but can affect the stability of the resulting class I‐peptide interaction. The dissociation of peptides with modified and, more generally, suboptimal anchor residue side chains may explain the presence of empty class I molecules and free class I heavy chains at the cell surface.
Differential induction of T cell cytokine mRNA in Epstein‐Barr virus‐transformed B cell clones: constitutive and inducible expression of interleukin‐4 mRNA
Authors: Tang Huayang , Matthes Thomas , Carballido‐Perrig Nicole , Zubler Rudolf H. , Kindler Vincent 
Published: March 2007

AbstractClones of human B lymphocytes, obtained after immortalization with Epstein‐Ban virus (EBV) of single CD 19+ B cells and expansion in the absence of human T lymphocytes, produced mRNA for the T cell cytokines interleukin(IL)‐2, IL‐4, and interferon(IFN)‐γ. As detected by reverse transcriptase‐polymerase chain reaction, IL‐2 mRNA was expressed only after stimulation with the combination of phorbol 12‐myristate 13‐acetate (PMA) plus ionomycin. IL‐4 mRNA was constitutively detectable in all (10/10) EBV‐transformed B cell clones, and the mRNA for IFN‐γ was constitutively present in half of the clones. In contrast to IL‐2 mRNA, the expression of IL‐4 and IFN‐γ mRNA could be increased by PMA alone. Most of the clones produced IL‐2 bioactivity and immunoreactive protein, but neither IL‐4 nor IFN‐γ protein secretion was detected. The intriguing question raised by these results is whether IL‐2 secretion could contribute to the immune control of EBV‐infected B lymphocytes by cytolytic T cells, and whether normal B lymphocytes can potentially be induced to express certain cytokines including IL‐4 in response to the appropriate activation signals.