bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of molecular components associated with surface immunoglobulin M in human B lymphocytes: Presence of tyrosine and serine/threonine protein kinases
Authors: Leprince Corinne , Draves Kevin E. , Ledbetter Jeffrey A. , Torres Raul M. , Clark Edward A. 
Published: March 2007

AbstractTo characterize the signal transduction through the antigen receptor (AgR) on human B lymphocytes, we analyzed its association with other molecular components. The surface IgM (sIgM) complex isolated in digitonin contains two surface expressed polypeptides ‐ the previously described Igα and Igβ proteins ‐ covalently linked to each other in a 48/39‐kDa heterodimer. We show herein that the human sIgM complex isolated from the Burkitt's lymphoma cell line, Ramos, or from dense tonsillar B cells contains additional molecules −160 kDa and 75 kDa in size — and enzymatic activities able to phosphorylate on tyrosine as well as serine/threonine residues the 39−, 48−, 75− and 160‐kDa polypeptides. By specific immunoprecipitation with antibodies to src‐family kinases, we consistently detected p56lyn in the sIgM complex. In the Ramos cell line, both p56lck and p59fyn activity were also observed, although to a much lesser extent than p56lyn. These kinases are associated with sIgM before cell stimulation. As shown by two‐dimensional electrophoresis, they interact in a tight complex with multimeric forms of the Igα and Igβ components. The kinases are active in vitro but must be highly regulated in vivo: Western blotting with anti‐phosphotyrosine antibodies revealed that stimulation of the AgR on viable B cells increased detectable phosphotyrosine residues on the components present in the sIgM complex. Based on these phosphorylation changes, the 39−, 48−, 75− and 160‐kDa molecules are likely to be functionally active elements in an IgM complex crucial for the transduction of the antigenic signal.
Nitric oxide mediates intestinal pathology in graft‐vs.‐host disease
Authors: Garside Paul , Hutton Angela K. , Severn Alison , Liew Foo Y. , Mc Mowat Allan I. 
Published: March 2007

AbstractWe have investigated the involvement of nitric oxide (NO) in intestinal graft‐vs.‐host reaction (GvHR) in mice. Treatment of mice with L‐NG‐monomethyl arginine (L‐NMMA), a specific inhibitor of NO synthesis, abolished the mucosal pathology of intestinal GvHR and reduced the associated lymphocytic infiltration of the epithelium. L‐NMMA had no effect on splenomegaly in GvHR, nor did it interfere with the growth of an undifferentiated crypt stem cell line, or the production of tumor necrosis factor‐α by activated macrophages in vitro. In contrast, L‐NMMA inhibited the enhanced activity of natural killer (NK) cells which occurs in GvHR. We conclude that a NO‐dependent mechanism is essential for intestinal immunopathology in GvHR and that this may reflect a role for NO in NK cell function.
Attenuation of autoimmune disease and lymphocyte accumulation in MRL/lpr mice by treatment with anti‐Vβ8 antibodies
Authors: De Alborán Ignacio M. , Gonzalo José A. , Kroemer Guido , Leonardo Esther , Marcos Miguel A. R. , Carlos Martínez‐A. 
Published: March 2007

AbstractMRL‐MP‐lpr/lpr mice are afflicted by a severe systemic autoimmune disease that is aggravated by the lpr mutation resulting in the accumulation of phenotypically abnormal lpr cells (CD3+CD4−CD8−) in all lymphoid issues including hyperplastic lymph nodes. Given that products of the T cell receptor Vβ8 gene family are overrepresented among lpr cells, different schedules aimed at selectively decreasing the frequency of lpr cells were designed. First, continuous administration of the monoclonal antibody F23.1 (specific for Vβ8 products) resulted in a significant depletion of Vβ8+ cells and prevented the manifestation of lymph accumulation at the same time as it reduced the serological, clinical, and histopathological signs of autoimmune disease. Along the same line, administration of either F23.1 or two different anti‐F23.1 anti‐idiotypic antibodies to MRL/Mp‐lpr/lpr mothers elicited, in the offspring, the production of antibodies sharing a recurrent idiotype with F23.1 and resulted in long‐term amelioration of autoimmunity and lymphadenopathy. Thus, a strategy aimed at specifically reducing the frequency of a subset of lpr cells proved successful in mitigating the autoimmune process.
The specificity and efficiency of endogenous peptides in the induction of HLA class I α chain refolding
Authors: Tanigaki Nobuyuki 
Published: March 2007

AbstractThe specificity and efficiency of endogenous peptides in the HLA class I binding have been investigated by the use of a simple procedure that is based on the serological detection of the folding of HLA class I α chains that is induced by the binding to specific peptides in the presence of β2 microglobulin. HLA class I proteins were solubilized with a nonionic detergent from cultured HLA homozygous B lymphoblastoid cells and dissociated by alkaline denaturation. The resulting unfolded α chains were isolated by gel filtration at a neutral pH. The unfolded α chains showed a high refolding capacity and specificity when tested in the presence of an excess β2 microglobulin against endogenous peptides extracted by alkaline or acid treatment from cultured B lymphoblastoid cells of various HLA class I phenotypes. Cells of identical or overlapping HLA phenotypes clearly showed shared peptides, whereas such peptide sharing was rarely, if at all, seen between cells of non‐overlapping HLA phenotypes. The efficiency of endogenous peptides in the induction of refolding was high; at an estimated concentration of 0.2 μM or less, a strong refolding effect was observed.
Presence of CD8α‐CD8β‐positive TcR γ/δ thymocytes in the fetal murine thymus and their in vitro expansion with interleukin‐7
Authors: Leclercq Georges , De Smedt Magda , Plum Jean 
Published: March 2007

AbstractSeveral groups have described that a low percentage of in vitro cultured T cell receptor (TcR) γ/δ cells express CD8. Contrary to TcR α/β cells, however, CD8 on these TcR γ/δ cells was shown to be a CD8α homodimer. We describe here that addition of interleukin‐7 (IL‐7) to a short‐term in vitro culture of fetal day 14 thymic lobes in an organ culture system or of fetal day 18 fetal thymocytes in cell suspension yields CD8β‐positive TcR γ/δ cells. This is not the result of IL‐7‐induced expression of CD8β on previously CD8β‐negative cells. It is due to IL‐7‐induced expansion of CD8α‐CD8β‐positive TcR γ/δ cells which are shown to be present in the starting fetal thymocyte cell population.
Cytotoxic T lymphocyte responses in the peripheral blood of children born to human immunodeficiency virus‐1‐infected mothers
Authors: Cheynier Rémi , Langlade‐Demoyen Pierre , Marescot Marie‐Rose , Blanche Stephane , Blondin Gilles , Wain‐Hobson Simon , Griscelli Claude , Vilmer Etienne , Plata Fernando 
Published: March 2007

AbstractCytotoxic T lymphocytes (CTL) are present at high activities in adult patients infected with the human immunodeficiency virus (HIV). In this report, CTL effectors were identified in peripheral blood mononuclear cells (PBMC) of children born to HIV‐1‐infected mothers. These CTL killed HLA‐matched HIV‐1‐infected H9 target cells or doubly transfected P815‐A2‐env, gag or nef mouse tumor cells, which expressed the viral antigens in association with HLA‐A1/A3 or HLA‐A2, respectively. HIV‐1‐specific CTL were detected early after birth (>2 months) and remained present during the asymptomatic phase of the infection. As in HIV‐1‐infected adults, HIV‐specific CTL declined with disease progression. Surprisingly, HIV‐1‐specific CTL were detected in the PBMC of three children who subsequently became seronegative.
Human monoclonal striational autoantibodies isolated from thymic B lymphocytes of patients with myasthenia gravis use VH and VL gene segments associated with the autoimmune repertoire
Authors: Victor Kimberly D. , Pascual Virginia , Williams Carol L. , Lennon Vanda A. , Capra J. Donald 
Published: March 2007

AbstractThe production of autoantibodies reactive with components of skeletal muscle is characteristic of myasthenia gravis (MG) and is strongly associated with the presence of thymic epithelial tumors in patients with MG. The nucleotide sequences of the heavy and light chain variable regions (VH and VL) of three human monoclonal striated muscle antibodies (StrAb) isolated from thymic B lymphocyte lines from two patients with MG and thymoma were analyzed. The VH and VL gene segments used by these anti‐striated muscle antibodies appear to be derived from the same repertoire of gene segments as have been found in other autoantibodies isolated from patients with a number of different autoimmune diseases. While the IgM StrAb SA‐1A is a direct copy of germ‐line VH and VL gene segments, analysis of the IgG StrAb SA‐4A and SA‐4B, which may be more representative of antibodies found in the serum of MG patients, suggests that the processes of antigenic selection and somatic mutation may contribute to the generation of autoantibodies in MG.
Association of the human invariant chain with H‐2 Db class I molecules
Authors: Cerundolo Vincenzo , Elliott Tim , Elvin John , Bastin Judy , Townsend Alain 
Published: March 2007

AbstractWe describe two proteins of 24 kDa and 33 kDa (p24 and p33) which associate with H‐2 Kb and H‐2 Db molecules, respectively, in human cells transfected with H‐2 Kb and H‐2 Db genes. This association is particularly clear in the mutant cell line T2, in which association of endogenous peptide with newly synthesized class I molecules may not occur (V. Cerundolo et al., Nature 1990. 345: 449). We show that p33 is the 33‐kDa form of the human invariant chain which is resident in the endoplasmic reticulum of T2 cells (P. Cresswell, Cold Spring Harbor Symp. Quant. Biol. 1989. LIV: 309). The stability of the invariant chain H‐2 Db complex is critically dependent upon occupation of the class I binding site by peptide ligand. In the absence of peptide, the complex is stable at 4°C whereas following exposure to peptide, the invariant chain dissociates rapidly from H‐2 Db molecules (half‐life of 30 min at 4°C). Although the interaction between the human invariant chain and murine H‐2 Db is unlikely to have any functional significance, the peptide‐induced dissociation of the invariant chain is consistent with a conformational change in H‐2 Db on peptide binding.
Mouse tumor rejection antigens P815A and P815B : Two epitopes carried by a single peptide
Authors: Lethé Bernard , Van den Eynde Benoǐt , Van Pel Aline , Corradin Giampietro , Boon Thierry 
Published: March 2007

AbstractMouse mastocytoma P815 expresses several distinct tumor rejection antigens recognized by syngeneic cytolytic T lymphocytes (CTL). Two of these tumor rejection antigens, P815A and P815B, are encoded by gene P1A, the sequence of which was reported previously. Tumor cell variants having lost one or both of these antigens were isolated by in vitro selection with CTL and also by collecting tumor cells that progressed in vivo after escaping a nearly complete immune rejection process. The structure of gene P1A in these antigen‐loss variants was examined. Several A−B− variants presented a complete or partial deletion of the gene. One variant that had lost only antigen A displayed a point mutation in the first exon. Peptides were synthesized that corresponded to the normal sequence located in the region of this point mutation. They sensitized target cells to both anti‐A and anti‐B CTL. The homologous peptide encoded by the mutated gene of the P815 A−B+ variant sensitized cells only to anti‐B CTL. We conclude that anti‐A and anti‐B CTL recognize on the same peptide two distinct epitopes that are affected differently by the mutation.
Enhancers of nonspecific immunity induce nitric oxide synthase: Induction does not correlate with toxicity or adjuvancy
Authors: Palacios Miriam , Knowles Richard G. , Moncada Salvador 
Published: March 2007

AbstractA range of bacterial products and related synthetic compounds, either alone or in combination, enhance nonspecific resistance to infection and tumors. These compounds, which vary in their other properties such as pyrogenicity, toxicity and adjuvancy, were used to assess the hypothesis that nonspecific resistance is mediated by induction of the L‐arginine: nitric oxide (NO) pathway. The results obtained show that agents which stimulate nonspecific immunity, such as endotoxin, muramyl dipeptide (MDP) and combinations of monophosphoryl lipid A (MPL) with either trehalose dimycolate (TDM) or MDP cause a substantial induction of Ca2+‐independent NO synthase in murine lung. In contrast, agents which do not stimulate nonspecific resistance, such as either MPL or TDM alone or threonyl MDP (ThrMDP), do not induce NO synthase. This difference in the ability of MDP and ThrMDP to induce NO synthase in the lung in vivo was also manifest in peritoneal macrophages in vivo as well as being evident in the > 100‐fold greater potency of MDP in inducing the enzyme in vitro in lung slices. In contrast to the good correlation between induction of NO synthase and induction of nonspecific resistance, no correlation was observed with either the toxic effects of these agents or their adjuvancy.
Mechanisms of resistance to Leishmania aethiopica. I. Interferon‐γ in combination with a cytokine (not tumor necrosis factor‐α) is required, but cannot act alone in the inhibition of intracellular forms of L. aethiopica in THP1 cells
Authors: Mohamed Abdi Muse , Taye Tesema , Akuffo Hannah O. 
Published: March 2007

AbstractFollowing exposure to promastigotes of various Leishmania species, mononuclear cells from non‐exposed as well as potentially exposed individuals produced a cytokine response which inhibited intracellular forms of Leishmania aethiopica in a permissive monocytic cell line (THP1). Interferon‐γ (IFN‐γ), was one of the cytokines responsible for this anti‐leishmanial effect. IFN‐γ was necessary for inhibition but could not act on its own in inhibiting L. aethiopica. Tumor necrosis factor‐α seemed not to be involved in the anti‐L. aethiopica effect. The observed effects were in the absence of endotoxin. The results suggest that the mechanisms of killing of L. aethiopica in human cells may differ from those responsible for inhibition of other Leishmania parasites (such as Leishmania major) in mouse macrophages. Furthermore, that potentially relevant responses to Leishmania antigens may exist in normal individuals.
Processing and presentation of intact hen egg‐white lysozyme by dendritic cells
Authors: De Bruijn Marloes L. H. , Nieland John D. , Harding Clifford V. , Melief Cornelis J. M. 
Published: March 2007

AbstractDendritic cells in lymphoid tissues are of key importance as highly specialized antigen‐presenting cells for the induction of T lymphocyte responses. Conflicting results have been published regarding antigen processing of intact proteins by dendritic cells. We now report that highly purified dendritic cells isolated from H‐2k mouse spleens very efficiently generated immunogenic fragments of intact hen egg‐white lysozyme (HEL) protein to present to an I‐Ak‐restricted T hybridoma cell line, specific for HEL peptide 46–61. Dendritic cells required 100 times less HEL protein than lipopolysaccharide‐induced B cell blasts for effective presentation. Uptake of 125I‐labeled HEL protein by dendritic cells and inhibition of presentation of HEL protein by chloroquine treatment was observed. This indicates an endocytotic process and the involvement of acidified compartments. Since the supernatant of dendritic cells, that were incubated with intact HEL protein, contained immunogenic fragments, further evidence for processing of HEL protein by dendritic cells was obtained. When HEL protein was covalently coupled to beads, dendritic cells were not able to ingest these beads, but could still process HEL protein for presentation. This suggests cell surface processing of HEL protein, although internalization of HEL protein released from the beads cannot be excluded. Taken together, these data show that H‐2k dendritic cells are capable of processing and presenting intact HEL protein.
Dependency on interleukin‐1 of primary human in vitro T cell responses to soluble antigens
Authors: Plebanski Magdalena , Elson Chris J. , Billington W. David 
Published: March 2007

AbstractThe role of interleukin (IL)‐1 in antigen‐specific activation of naive human T cells has been examined. Primary human T cell proliferative responses to the soluble antigen keyhole limpet hemocyanin (KLH) were decreased by neutralizing antisera to IL‐1α (25 ± 7 % standard error) and IL‐1β (56 ± 6 % standard error). Inhibition by both antisera in a primary culture was usually additive. Recombinant IL‐1α and recombinant IL‐1β could both re‐establish responses in cultures blocked by neutralizing anti‐IL‐1β Interestingly, the susceptibility of KLH‐stimulated T cell responses to inhibition by neutralizing anti‐IL‐1 sera decreased with time in culture. This observation suggested that T cell responses may become less IL‐1 dependent as T cells become activated or primed. In support of this notion, secondary T cell responses to purified protein derivative from Mycobacterium tuberculosis (PPD) were markedly less affected by the addition of comparable amounts of the neutralizing anti‐IL‐1 sera. These results demonstrate that IL‐1 is one of the main co‐stimulators for primary T cell activation and suggest a different requirement for IL‐1 in the activation of naive compared to memory human T cells.
Identification of a surface protein (p100) associated with two glycosyl‐phosphatidylinositol‐linked molecules (Thy‐1 and ThB) by natural anti‐lymphocyte autoantibodies
Authors: Lehuen Agnès , Monteiro Renato C. , Kearney John F. 
Published: March 2007

AbstractOur previous study of natural autoantibodies showed that anti‐lymphocyte antibodies are frequently produced by perinatal B cells from normal strains of mice. One‐third of these monoclonal antibodies (mAb) recognized similar epitopes on the surface of thymocytes. In the present report, we have characterized the molecule recognized by three of these mAb (D10, G7, 22). These mAb identified a 100‐kDa protein (p100) on the surface of thymocytes. This protein resolved into 70‐kDa polypeptide chains under reducing conditions. Inhibition experiments as well as antibody immunoprecipitations in the presence of mild detergents revealed non‐covalent association of the p100 with Thy‐1 and ThB. A similar multimolecular complex was identified following chemical cross‐linking of thymocyte surface proteins. Analysis of several Thy‐1‐defective mutant cells lines, and thymocytes treated with phosphatidylinositol‐specific phospholipase C (PI‐PLC) showed that the expression of p100 was strongly influenced by Thy‐1 molecule. The p100 was resistant to PI‐PLC treatment and was not released into the supernatant as was the case for Thy‐1 and ThB molecules. These data lead us to propose that the p100 is a transmembrane protein, the expression of which in the plasma membrane is dependent on the association or presence of Thy‐1 molecule.
Mast cells contribute to fibrin deposition in reverse passive Arthus reaction in mouse skin
Authors: Ramos Bernard F. , Zhang Yan , Jakschik Barbara A. 
Published: March 2007

AbstractThe activation of the clotting system is an important process during inflammation to contain the injury and initiate tissue repair. In the present study, we investigated the effect of mast cells on fibrin deposition in reverse passive Arthus reaction in mast cell‐deficient WBB6F1‐W/WV(W/WV) and control WBB6F1‐+/+(+/+) mice, that were given 125I‐labeled fibrogen intravenousty. An antibody dose‐dependent increase in radioactivity was observed in the challenged skin sites. Sequential water and urea extractions characterized the radioiodinated fibrinogen derivatives present in the tissue. The radioactivity found in the various fractions of the stimulated samples from +/+ was 2–10‐fold higher than that in specimens from W/WV mice. The greatest difference was observed in the urea‐insoluble pellet (cross‐linked fibrin and its early degradation products). Reconstitution of W/WV mice with mast cells augmented the response to levels similar to those in +/+ mice. Pretreatment with the antihistamine pyrilamine blocked the accumulation of 125I‐labeled fibrinogen and its derivatives by approximately 70% in +/+ but not in W/WV mice. Inhibition of leukotriene synthesis by A‐63162 markedly decreased the accumulation of iodinated fibrinogen in both +/+ and W/WV mice. The data suggest that mast cells and their vasoactive mediator histamine contribute to the exudation of clotting factors, which results in fibrin deposition and that mast cells also enhance fibrin cross‐linkage.
Anti‐insulin and regulatory anti‐idiotypic antibodies use the same germ‐line VHIX gene
Authors: Thomas James W. 
Published: March 2007

AbstractIn humans and in BALB/c mice, immune responses to the hormone insulin use evolutionarily related VHV (human) and VHIX (murine) gene families. To determine if these structural relationships include regulatory elements, BALB/c mice were pretreated with autologous immunoglobulin G (IgG) monoclonal antibodies (mAb) that recognize shared idiotopes on human anti‐insulin antibodies and the subsequent immune response to human insulin assessed. One mAb, Id227, was found to augment and accelerate the insulin response by inducing a human idiotype that is expressed on both insulin‐binding and non‐insulin‐binding BALB/c antibodies. Analysis of VH gene utilization by Id227 shows that it expresses a VHIX gene similar to that of anti‐insulin mAb 125, but the anti‐Id has no anti‐insulin activity. Using DNA amplification, four germ‐line VHIX genes were isolated from BALB/c liver DNA and sequence analysis shows that the anti‐insulin and anti‐Id are derived from the same germ‐line gene. Consistent with its role as a regulatory idiotype, IgG Id227 entirely preserves germ‐line sequence in the complementray determining regions and contains only three mutations in framework regions. These studies show that both structural and regulatory features of immune responses to conserved self antigens extend beyond species boundaries.
Biochemical evidence of the physical association of the majority of CD3 δ chains with the accessory/co‐receptor molecules CD4 and CD8 on nonactivated T lymphocytes
Authors: Suzuki Satoru , Kupsch Jörg , Eichmann Klaus , Saizawa Mitsuyoshi K. 
Published: March 2007

AbstractThe association of components of the CD3 complex with the accessory molecules CD4 and CD8 was studied by immunoprecipitation experiments followed by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) analysis. Enhanced surface iodination was achieved by a water‐soluble derivative of the Bolton‐Hunter reagent. Using freshly isolated nonactivated splenic T cells, we find that antibodies to CD4 and to CD8 strongly co‐precipitate a 28‐30‐kDa band identical in mobility to the δ chain of the CD3 complex. Components corresponding in mobility to the ε and γ chains of the CD3 complex are also co‐precipitated but to a much lesser extent. The identity of the co‐precipitated 28‐30‐kDa material with the CD3 δ chain was ascertained by two‐dimensional nonreducing/reducing SDS‐PAGE, by two‐dimensional non‐equilibrium pH gradient electrophoresis/SDS‐PAGE and by one‐dimensional peptide mapping with three different proteases. The co‐precipitated 28‐30‐kDa material was identical to the CD3 δ chain by all these criteria. Quantitative analyses by densitometric gel tracing revealed that the amounts of CD3 δ co‐precipitated with anti‐CD4 and anti‐CD8 add up to those in anti‐Vβ precipitates and to an average of 90% of those in anti‐CD3ε precipitates. We conclude that the majority of CD3 δ chains are associated with the accessory/co‐receptor molecules CD4 or CD8 on resting T cells, and that this association is independent of antigen‐specific recognition by the T cell receptor.