bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variable region sequences of autoantibodies from mice with experimental systemic lupus erythematosus
Authors: Waisman Ari , Mozes Edna 
Published: March 2007

AbstractWe have sequenced nine monoclonal antibodies (mAb) derived from C3H.SW mice in which experimental systemic lupus erythematosus (SLE) was induced. The hybridomas were selected for binding to DNA or to HeLa nuclear extract (NE). Three mAb were found to bind DNA, and are shown to exhibit sequence characteristics of pathogenic anti‐DNA antibodies. One, mAb 2C4C2, is shown to use a heavy chain V region gene (VH) identical to the VH of anti‐DNA mAb isolated from other lupus‐prone mice, namely (NZB × NZW)F1. The light chain V region gene (VL) of mAb 2C4C2 is 98 % homologous to the VL of another anti‐DNA mAb, also isolated from (NZB × NZW)F1 mice. The other two anti‐DNA mAb, 5G12‐4 and 5G12‐6, share 93 % of their VH sequences with that of mAb 2C4C2. Six mAb bound proteins of HeLa NE. Four of these six antibodies were found to use the VH124 VH and V‐L7 VL. The nine mAb use a total of five VH and four VL germ‐line genes, demonstrating that the autoantibodies induced in mice with experimental SLE do not originate from one B cell clone. Three of these nine VH and VL were identical in sequence to germ‐line genes, while at least three others had somatic mutations. The latter suggests that the above autoantibodies arise in mice by both usage of existing (pre‐immune) B cells, and through an antigen‐driven process. Furthermore, it appears that autoantibodies found in mice with experimental SLE use genetic elements similar to those used by mAb that were isolated from mouse strains which develop lupus spontaneously.
Minute quantities of a single immunodominant foreign epitope are presented as large nested sets by major histocompatibility complex class II molecules
Authors: Vignali Dario A. A. , Urban Robert G. , Chicz Roman M. , Strominger Jack L. 
Published: March 2007

AbstractThe processing and presentation of immunogenetic peptides is an obligate event in the generation of an immune response. However, the degree of complexity with which an immunogenic foreign epitope is presented is still unclear. This question was addressed by analyzing the naturally processed peptides generated from exogenously‐derived hen egg white lysozyme (HEL) bound to the murine major histocompatibility complex (MHC) class II molecule, H‐2Ak. Using reversed‐phase chromatography (RPC), T cell hybridomas and mass spectrometry, 16 peptides were identified that contain the minimal MHC binding epitope 52–61. These peptides exhibited substantial N‐ and C‐terminal extensions and ranged from 13–28 amino acids in length. In contrast, MHC class I molecules present peptides of 8–11 residues and each foreign epitope appears to be represented by only a single peptide. The data here also show that only ∼ 0.8% of the total bound peptide was derived from this single HEL epitope. These findings provide direct evidence that relatively small amounts of processed peptide are required to stimulate an effective T cell response.
CD3‐mediated apoptosis of human medullary thymocytes and activated peripheral T cells: Respective roles of interleukin‐1, interleukin‐2, interferon‐γ and accessory cells
Authors: Groux Hervé , Monte Didier , Plouvier Benedicte , Capron Andre , Ameisen Jean‐Claude 
Published: March 2007

AbstractClonal deletion represents an important mechanism for the establishment of tolerance, by the elimination of autoreactive T cells. Deletion is accomplished by programmed cell death, termed apoptosis, induced by mobilization of the T cell receptor (TCR) on both thymocytes and mature T cells. The mechanism which drives T cells towards cell death or cell proliferation after TCR mobilization remains unclear. We show here that the mobilization of the CD3/TCR complex of both CD4+ and CD8+ single‐positive medullary human thymocytes and human mature activated T cells, in the absence of accessory cells, leads to an activation‐induced cell death process by apoptosis. In both cases, apoptosis was associated with interferon (IFN)‐γ gene expression and secretion in the absence of interleukin (IL)‐2 gene expression; and the addition of anti‐IFN‐γ antibody prevented cell death. Apoptosis could also be prevented by cyclosporin A (CsA) treatment and could be re‐induced by the addition of IFN‐γ to CsA‐treated cells. Addition of IL‐2 had two different effects, it prevented apoptosis and also allowed proliferation in response to CD3 monoclonal antibody. Addition of IL‐1, which induces IL‐2 gene expression and secretion or addition of accessory cells, had the same preventive effect. These results suggest that the uncoupling of IFN‐γ and IL‐2 gene expression following CD3/TCR mobilization initiates apoptosis of human T cells at several different stages during development and activation. We propose that co‐signals provided by accessory cells allow a coupling of IL‐2 gene and IFN‐γ gene expression, and that an essential role for IL‐2 secretion in T cell activation involves the inhibition of a death program induced by IFN‐γ secretion.
CD23 and CD21 function as adhesion molecules in homotypic aggregation of human B lymphocytes
Authors: Björck Pia , Elenström‐Magnusson Carina , Rosén Anders , Severinson Eva , Paulie Staffan 
Published: March 2007

AbstractWe have previously found that interleukin‐4 and CD40 monoclonal antibodies (mAb) are strong potentiatiors of homotypic B cell aggregation which is dependent on LFA‐1. We show here that CD23 mAb were also able to inhibit aggregation to a similar extent as LFA‐1 antibodies. This inhibition was restricted to the MHM6 epitope of CD23 and antibodies to other epitopes [Epstein‐Barr virus (EBV) CS‐1, EBV CS‐2, EBV CS‐5 and mAb 25] or occupation of the Fc‐binding site by IgE had no or a slightly enhancing effect on aggregation. When testing two antibodies to CD21, the recently defined ligand for CD23, one of these (BU32) was found to be inhibitory whereas the other (THB5) had no effect. By combining antibodies to LFA‐1 and CD23, aggregation was often completely inhibited. These data suggest that LFA‐1/ICAM‐1 and CD23/CD21 are the major molecules involved in homotypic aggregation of human B cells.
Cholera toxin adjuvant greatly promotes antigen priming of T cells
Authors: Hörnquist Elisabeth , Lycke Nils 
Published: March 2007

AbstractCholera toxin (CT) given perorally is a powerful mucosal immunogen and adjuvant. Information that explains the adjuvant effect of CT may be used for the development of more effective oral vaccines and might also contribute to our understanding of the mechanisms involved in regulating mucosal immunity. The present study was undertaken to investigate if CT administered together with keyhole limpet hemocyanin (KLH) would act to promote or inhibit priming of KLH‐specific T cells and whether the adjuvant effect of CT is restricted to mucosal immune responses or is a generalized phenomenon due to direct immunomodulating effects of CT. We found that CT adjuvant greatly augmented the effectiveness of a single oral priming immunization with KLH: re‐challenge with KLH in vitro 1 week following immunization gave several‐fold stronger proliferation in KLH‐specific spleen, mesenteric lymph node, Peyer's patch and gut lamina propria T cells from KLH + CT adjuvant as opposed to KLH only‐treated mice. Moreover, several‐fold stronger cytokine production, i.e. interleukin (IL)‐2, IL‐4, IL‐5, IL‐6, IL‐10 and interferon‐Y accompanied the enhanced proliferative response of T cells from CT adjuvant‐treated mice. The adjuvant effect of CT was not restricted to mucosal immune responses but was evident also following a single parenteral immunization with KLH + CT. Limiting dilution analysis revealed that CT adjuvant promoted a 20‐ to 40‐fold increase in the frequency of primed KLH‐specific T cells. Phenotypic and functional analyses clearly demonstrated that CT adjuvant primarily enhanced priming of CD4+ rather than CD8+ T cells and the pattern of lymphokine secretion disclosed that CT most probably promoted antigen priming of both Thl and Th2 type of CD4+ T precursor cells.
Interleukin‐4 and interleukin‐10 synergize to inhibit cell‐mediated immunity in vivo
Authors: Powrie Fiona , Menon Satish , Coffman Robert L. 
Published: March 2007

AbstractThe lack of cell‐mediated (Thl‐like) immunity that is often associated with strong humoral immune responses is thought to be due in part to the inhibition of Th1 effector function by the Th2‐derived cytokine interleukin‐10 (IL‐10). This hypothesis, however, is based entirely on results from in vitro studies, wherein IL‐10 has been shown to inhibit Thl cytokine synthesis. In this study we have compared the regulatory effects of both IL‐4 and IL‐10 on the development of a more complex Thl effector function in vivo, the development of delayed‐type hypersensitivity (DTH) to Leishmania major in mice immune to Leishmania. The results revealed two findings unexpected from in vitro studies with Thl clones. First, optimal inhibition of the DTH response (up to 70 %), assessed by footpad swelling and leukocytic infiltration, required the combination of IL‐4 and IL‐10, indicating that these two activities synergized to inhibit DTH reactivity. Second, IL‐4 inhibited interferon‐γ (IFN‐γ) production by lymph node cells draining the site of antigen challenge as well as did IL‐10. The combination of both cytokines was no more effective than either alone. The mechanism by which IL‐4 and IL‐10 acted to inhibit DTH responses did not appear to be through inhibition of IFN‐y or tumor necrosis factor production as treatment with antibodies which neutralized these activities failed to inhibit DTH responses. Inhibition of the DTH with IL‐4 and IL‐10 is the most effective specific regulator of DTH responses reported and the only one capable of modulating tuberculin DTH. These data establish IL‐4 and IL‐10 as potent inhibitors of Thl effector function in vivo and suggest their utility in controlling deleterious Thl‐mediated inflammatory responses such as occur in some infectious and autoimmune diseases.
Class I‐deficient resistant mice intracerebrally inoculated with Theiler's virus show an increased T cell response to viral antigens and susceptibility to demyelination
Authors: Pullen Lara C. , Miller Stephen D. , Dal Canto Mauro C. , Kim Byung S. 
Published: March 2007

AbstractIntracerebral inoculation of Theiler's murine encephalomyelitis virus (TMEV) results in immune‐mediated demyelination in susceptible mouse strains. The histology of TMEV‐induced demyelination is similar to that seen in patients suffering from multiple sclerosis. It was previously shown that the susceptibility of mice to TMEV‐induced demyelination in certain strain combinations is closely associated with the major histocompatibility complex (MHC) class I locus. Here we examine disease susceptibility of β2‐microglobulin (β2M)‐deficient transgenic mice lacking class I expression and functional CD8+ T cells. In contrast to TMEV‐infected parental C57BL/6 mice, the transgenics develop high levels of virus‐specific DTH and T cell proliferation accompanied by an increased frequency of central nervous system (CNS) demyelinating lesions. However, clinical signs of demyelination were not noted. Neither antibody titer nor viral persistance were significantly affected in the β2M‐deficient mice. These results suggest that in the absence of functional class I/CD8+ cells, the class II‐restricted T cell response to TMEV is enhanced and CNS pathogenesis is heightened, although the level is not severe enough to result in clinical disease. When the TMEV‐infected mice were subcutaneously immunized with virus, however, the β2M‐deficient mice displayed clinical symptoms. Therefore, our results strongly suggest that CD8+ T cells do not directly contribute to CNS demyelination. In contrast, such T cells appear to be primarily involved in down‐regulation of a potentially damaging CD4+ T cell response in resistant animals, although some of the T cells may play a role in clearing viral persistence in the CNS, resulting in the protection of the host from viral demyelination.
Identification and expression of two forms of the human transforming growth factor‐β‐binding protein endoglin with distinct cytoplasmic regions
Authors: Bellón Teresa , Corbi Angel , Lastres Pedro , Calés Carmela , Cebrián Marta , Vera Sonia , Cheifetz Sela , Massague Joan , Letarte Michelle , Bernabéu Carmelo 
Published: March 2007

AbstractEndoglin is an homodimeric membrane antigen with capacity to bind transforming growth factor‐β (TGF‐β) and whose expression is up‐regulated on myeloid cells upon differentiation to macrophages. We have isolated full‐length cDNA clones from a λgtl0 library, prepared from phorbol 12‐myristate 13‐acetate‐differentiated HL60 cells by screening with an endoglin‐specific cDNA probe from endothelial cells. Sequencing of the largest clone (3073 bp), revealed that the leader sequence contains 25 residues and that the 586 amino acids of the extracellular and transmembrane domains were identical to those described for endothelial endoglin. However, the cytoplasmic tail encoded by this cDNA clone contains only 14 amino acids as opposed to the 47 residues previously reported, suggesting the existence of two alternative endoglin variants. The expression of these isoforms was demonstrated by polymerase chain reaction analyses on endothelial cells, myelomonocytic cell lines HL‐60 and U‐937, and placenta. Independent cDN A constructs corresponding to both forms were transfected into mouse fibroblasts leading to the expression of two distinct endoglin molecules. Both forms were shown to bind TGF‐β1 and, when overexpressed in transfected mouse fibroblasts, to form disulfide‐linked homodimers, indicating that the cysteine residues present in the extracellular domain are responsible for the dimerization.
Kinetic study of interleukin‐2 binding on the reconstituted interleukin‐2 receptor complexes including the human γ chain
Authors: Matsuoka Mitsuo , Takeshita Toshikazu , Ishii Naoto , Nakamura Masataka , Ohkubo Takao , Sugamura Kazuo 
Published: March 2007

AbstractTo gain an insight into roles of the interleukin‐2 (IL‐2) receptor γ chain in IL‐2 binding mechanisms, we examined association and dissociation rate constants for IL‐2 binding with a series of fibroblastoid L929 cell lines expressing IL‐2 receptor complexes reconstituted by transfection with the α, β and γ genes. The association rate constant (k) with the αβγ complex on L cells was fourfold larger than that with the αβ complex on L cells, and the dissociation rate constant (k') was one fifth of that with the αβ complex. These results indicate that the γ chain is involved in both mechanisms by which IL‐2 associates with and dissociates from receptors, resulting in the generation of the high‐affinity IL‐2 receptor along with the α and β chains. During the course of this study, we found that the IL‐2 dissociation from αβγ complex on lymphoid cells was a lot slower than that from the αβγ complex on fibroblast cells. A similar difference was observed with the βγ complex. These observations may indicate functional and constitutional differences of the high‐ and intermediate‐affinity IL‐2 receptor complexes between lymphoid and fibroblastoid cells.
Signaling via CD28 costimulates lymphokine production, but does not reverse unresponsiveness to interleukin‐2 in anti‐CD3 triggered Th1 cells
Authors: Sommer Frank , Röllinghoff Martin , Lohoff Michael 
Published: March 2007

AbstractPreviously, it has been described that the ability of murine Th1 cells to proliferate in response to exogenous interleukin (IL)‐2 is blocked when these cells are exposed to immobilized anti‐CD3 antibodies. In the present study we examined whether simultaneous triggering of the T cell antigen CD28 can prevent the induction of unresponsiveness to IL‐2 in Th1 cells. We report that costimulation of Th1 cells with anti‐CD28 monoclonal antibodies (mAb) did not overcome unresponsiveness to IL‐2 induced by various amounts of immobilized anti‐CD3 antibodies. However, stimulation with anti‐CD28 mAb strongly augmented IL‐2 and interferon‐γ production in anti‐CD3‐exposed Th1 cells. Thus, despite the fact that anti‐CD28 mAb is a potent costimulus for lymphokine production, signaling through CD28 does not seem to be sufficient to trigger proliferation in Th1 cells activated via the T cell receptor. These data suggest the existence of at least three signals to trigger Th1 cell activation. The first is mediated by ligation of the T cell receptor. One cosignal, delivered by the CD28 molecule, leads to IL‐2 production. A third, still undefined, signal is required for proliferation in response to IL‐2.
Surface phenotype and functions of tumor‐infiltrating dendritic cells: CD8 expression by a cell subpopulation
Authors: Chaux Pascal , Hammann Arlette , Martin François , Martin Monique 
Published: March 2007

AbstractAlthough the function and significance of tumor‐infiltrating dendritic cells (TIDC) in the immune response to tumor have never been clearly demonstrated, their location suggests that they play a critical role in the presentation of tumor antigen to specific T cells. We studied the morphological and functional characteristics of interstitial dendritic cells (DC) located inside tumors obtained by injection of cancer cells into syngeneic rats. Single and double immunostaining of tumor sections revealed a dense network of cells which expressed class II major histocompatibility complex (MHC II) molecules. Cell morphology and surface markers were characteristic of DC populations in other tissues. These DC were in close contact with tumor cells and increased in number as the tumor grew larger. Unexpectedly, a subpopulation of morphologically characteristic TIDC expressed both CD8 and MHC II molecules. TIDC were purified from tumors by gradient centrifugation and immunobeads and characterized by morphology, ultrastructural study and surface markers studied by flow cytometry. TIDC were negative for the CD5 molecule (a pan T cell marker), and were not labeled with 3.2.3 monoclonal antibody (mAb) (an NK cell marker) or with Ki‐M2R mAb (a macrophage marker). A subpopulation of TIDC expressed the CD8 molecule, confirming the in situ results. TIDC expressed high levels of class I and class II MHC molecules and the adhesion molecule ICAM‐1. This expression is compatible with effective antigen presenting function. Purified TIDC triggered rapid and high levels of proliferation of tumor‐immune T cells in vitro, demonstrating the potential of these cells to constitutively process and present tumor‐associated antigens.
In vitro negative selection of αβ T cell receptor transgenic thymocytes by conditionally immortalized thymic cortical epithelial cell lines and dendritic cells
Authors: Tanaka Yujiro , Mamalaki Clio , Stockinger Brigitta , Kioussis Dimitris 
Published: March 2007

AbstractWe have established conditionally immortalized thymic cortical epithelial cell lines from transgenic mice carrying a temperature‐sensitive SV40 large Tantigen. One of these cell lines expresses cortical markers and produces IL‐1α, IL‐6, IL‐7, and TGF‐β1. These cells express class I major histocompatibility complex (MHC) constitutively and class II MHC upon induction with IFN‐μ. The cells appear to have a normal class I antigen presenting pathway since messages for both peptide transporter genes (TAP1, TAP2) were detected.The ability of these cortical epithelial cells to present peptide antigen was compared to that of thymic dendritic cells. In suspension culture with αβ Tcell receptor (TcR) transgenic thymocytes, these epithelial cells and dendritic cells (pre‐pulsed with peptide cognate for the transgenic TcR) caused down‐regulation of CD4, CD8, and TcR in an antigen dose‐dependent and MHC‐restricted manner. CD4dullCD8dull cells were taken as evidence for negative selection because these cells contained apoptotic DNA. Concentration of peptide required for negative selection of thymocytes was similar between dendritic cells and cortical epithelial cells. In contrast, αβ transgenic spleen cells were activated only by dendritic cells but not by cortical epithelial cells.
Early B cell development requires μ signaling
Authors: Iglesias Antonio , Nichogiannopoulou Aliki , Stuart Williams G. , Flaswinkel Heinrich , Köhler Georges 
Published: March 2007

AbstractIn vitro studies with Abelson murine leukemia virus (AMuLV)‐transformed murine pre‐B cell lines demonstrated that wild‐type μ but not mutant μ chains lacking the first constant domain (μΔl) can efficiently induce Ig light (L) chain gene rearrangement. Using antibodies against the cytoplasmic tail of the immunoglobulin co‐receptor β (Igβ) chain we find μ., but not μA1 chains associated with Igμ. Since a heterodimer of surface‐labeled proteins was co‐precipitated with n we conclude that only wild‐type μ is associated with the Igα/Igβ co‐receptor on the surface of pre‐B cell lines. Mutant μΔ1 chains achieve their surface expression by utilizing a glycophospholipid anchor. In vivo analysis of transgenic mcie expressing either μ or μΔ1 transgenes revealed the expected “normal” B cell development in the case of wild‐type μ, transgenic lymphocytes, but a block in differentiation of μΔ1 transgenic lymphocytes. The maturation block occurs at the developmental transition of pre‐B lymphocytes from the CD43/S7+, CD45R/B220low stage to the CD43/S7−, B220low/hi8h stage in which the majority of L chain gene rearrangements occur. These results, together with the observed inability of the μΔ1 chains to signal activation of L chain gene joining and to associate Igα/Igβ in pre‐B cell lines suggest that signals mediated by the protein complex composed of μ/Igα/Igβ are crucial during differentiation of pre‐B lymphocytes.
The effect of bone marrow and thymus chimerism between non‐obese diabetic (NOD) and NOD‐E transgenic mice, on the expression and prevention of diabetes
Authors: Parish Nicole M. , Chandler Phil , Quartey‐Papafio Ruby , Simpson Elizabeth , Cooke Anne 
Published: March 2007

AbstractThe non‐obese diabetic (NOD) mouse is an established animal model of the autoimmune disease, insulin‐dependent diabetes mellitus (IDDM). The NOD‐E mouse is a transgenic mouse which expresses the I‐E molecule (absent in NOD mice). Expression of I‐E protects these mice from both insulitis and IDDM.We have investigated the possible mechanisms of this protection by constructing bone marrow, and combined bone marrow and thymus chimeras between NOD and NOD‐E mice.Our data suggest that thymic epithelium may play no direct role in either protection against, or promotion of, IDDM. Protection from diabetes is provided either by NOD‐E donor bone marrow or NOD‐E recipient non‐thymic radioresistant cells. The means by which protection may be achieved in this system are discussed.
Frequent occurrence of in vivo clonal expansion of CD4− CD8− T cells bearing T cell receptor αβ chains in adult humans
Authors: Kusunoki Yoichiro , Hirai Yuko , Hayashi Tomonori , Kyoizumi Seishi , Takahashi Keiko , Morishita Yukari , Kodama Yoshiaki , Akiyama Mitoshi 
Published: March 2007

AbstractWe have previously reported 2 cases of healthy men showing in vivo monoclonal expansion of mature CD4− CD8− αβ T cells. In the present study, an additional 3 adults were found to exhibit such an expansion, among a total 464 adult donors studied. These 5 individuals were otherwise physiologically normal, with no history of severe illness and autoimmune disease at the time of examination. To investigate the mechanisms of the clonal expansion, further characterization of the clonal cells was attempted. No apparent preference for usage of the Tcell receptor β chain variable region was observed in the clonal T cells. These clonal T cells showed lectin‐dependent or redirected antibody‐dependent cell‐mediated cytotoxicities, whereas they could not lyse autologous lymphoblastoid cell lines. Failure of Fas antigen expression was not observed for any of these clones. These results suggest that clonal expansion of CD4− CD8− αβ T cells frequently occurs in the periphery without any T cell abnormalities.