bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of VH residues 6 and 23 on IgG3 cryoprecipitation and glomerular deposition
Authors: Panka David J. , Salant David J. , Jacobsonn Bruce A. , Minto Andrew W. , Marshak‐Rothstein Ann 
Published: March 2007

AbstractMRL/lpr mice spontaneously develop a lupus‐like autoimmune syndrome characterized by immunopathologic manifestations such as necrotizing vasculitis of the skin and glomerulonephritis. A feature of this autoimmune syndrome is the production of extremely large amounts of monoclonal IgG3 cryoglobulins. The structural basis of IgG3 cryoprecipitation is not well understood. Although the IgG3 isotype is necessary for cyroprecipitation, not all IgG3 antibodies cryoprecipitate. It has been postulated that electrostatic charge may be influential in cryoprecipitation. To investigate this problem, the VH and VL sequences of a panel of IgG3 cryoglobulins and non‐cryoglobulins were compared, with particular attention to charged amino acid differences. At VH residues 6 and 23 the cryoglobulins were more positively charged than their non‐cryoglobulin counterparts. To analyze further the effect of charge on cryoprecipitation, the sequence of an IgG3 monoclonal cryoprecipitating rheumatoid factor was modified by site‐directed mutagenesis. The more positive residues at VH 6 and 23 present in some of the cryoglobulin antibodies were mutated to the more negative residues found in the non‐cryoglobulins. The results show that VH residue 6 affects cryoprecipitation while residue 23 does not. When injected into normal BALB/c mice, the unmutated antibody produced glomerular immune deposits and focal glomerulonephritis, whereas loss of cryoprecipitability by mutating residue 6 completely abrogated glomerular immune deposition and glomerular injury. In contrast, the mutation at residue 23 which retains cryoprecipitability reduced glomerular immune deposition and prevented glomerular injury.
Decay‐accelerating factor (CD55) protects human immunodeficiency virus type 1 from inactivation by human complement
Authors: Marschang Peter , Sodroski Joseph , Würzner Reinhard , Dierich Manfred P. 
Published: March 2007

AbstractHIV‐1 in contrast to animal retroviruses, is not lysed by human complement, but is readily inactivated by the sera from different animal species. To identify a possible species‐specific protection mechanism, HIV‐1 was expressed in cells of non‐human origin. Recombinant HIV‐1 virions that could encode the chloramphenicol acetyltransferase (CAT) protein were produced in African green monkey COS‐1 cells, mink cells and, as a control, in human HEp‐2 cells and were then used to infect CD4‐positive target cells. Analysis of the CAT activity of the target cells' revealed that fresh HIV‐1‐negative human serum reduced the infectivity of HIV‐1 derived from monkey and mink cells five‐ to tenfold, but had no effect on HIV‐1 produced in human cells. In addition, human serum efficiently lysed HIV‐1 produced in non‐human cells in contrast to HIV‐1 originating from human cells, suggesting lysis as an important mechanism of virus inactivation. Mammalian cells are protected against lysis by homologous complement by membrane‐bound regulatory molecules. Two of these complement inhibitors, namely decay‐accelerating factor (DAF) and, to a lesser extent, CD59 were found on the surface of HIV‐1 virions by means of a virus capture assay. Antibodies against DAF, but not against other host cell molecules found on the viral surface, efficiently blocked the resistance of HIV‐1 produced in human cells to human complement. These results suggest that the acquisition of DAF during the budding process from human cells protects HIV‐1 in a species‐specific way against the attack of human complement.
Expression of interleukin‐2 receptor γ on human monocytes: characterization of lineage specific post‐translational modifications
Authors: Epling‐Burnette P. K. , Wei Sheng , Liu Jin Hong , Pericle Federica , Ussery Dewayne , Russell Sarah M. , Leonard Warren J. , Djeu Julie Y. 
Published: March 2007

AbstractFunctional interleukin‐2 receptors (IL‐2R) on lymphocytes contain both IL‐2R β and γ chains. Whereas constitutive expression of IL‐2Rβ has been found on monocytes, the expression of IL‐2Rγ on these phagocytes has not been examined. We performed reverse‐transcription‐polymerase chain reaction with Southern blot analysis on RNA derived from purified human monocytes and discovered that they constitutively produce IL‐2Rγ mRNA. Western immunoblotting revealed 58‐and 64‐kDa forms of IL‐2Rγ on YT‐1 and human monocytes, whereas 58‐, 64‐, and 69‐kDa bands were detected using peripheral blood mononuclear cells and non‐adherent lymphocytes. These different forms resulted from variable N‐linked glycosylation since culture of the cells in tunicamycin resulted in detection of a single 39‐kDa band which corresponds to the molecular weight predicted from the deduced amino acid sequence. By co‐immunoprecipitation, the IL‐2Rβ subunit associates with only the 64‐kDa IL‐2Rγ protein band in monocytes.
Stimulation of χ transcription by a decamer‐dependent, synergistic mechanism
Authors: Sigvardsson Mikael , Bemark Mats , Leanderson Tomas 
Published: March 2007

AbstractThe intact SP6 χ promoter stimulated transcription 30 times more efficiently than did a control promoter consisting of a TATA motif as the only promoter element. Mutation of the SP6 χ promoter decamer in two positions reduced the transcriptional stimulation activity by over 90%. Promoters containing the SP6 χ promoter octamer or a consensus octamer in front of a TATA box were ineffective immunoglobulin promoters and stimulated at the most 15% of maximal transcription. Identical results were obtained after transfection of untransformed mouse splenic B cells stimulated by lipopolysaccharide, that express high levels of Oct2A, or of S194 cells that express negligible levels of Oct2A. Selective mutations in the penta‐decamer (pd), χY or early B cell factor (EBF) elements of the promoter reduced transcriptional stimulation by 20–30% in untransformed B cells. In S194 plasmacytoma cells the EBF mutation was functionally silent while the χY and pd mutations reduced transcriptional activation by 60‐70% in this cell line. A mutation in a TATA‐proximal E‐box motif did not alter the functional activity of the promoter in either cell population. It can be concluded that χ promoter function is highly dependent on complex interactions between individual promoter elements and that the decamer motif is pivotal for these interactions. The relative functional activity of a given promoter varied according to the target cell population used for the functional assay.
Individual differences in the orientation of the cytolytic T cell response against mouse tumor P815
Authors: Brichard Vincent G. , Warnier Guy , van Pel Aline , Morlighem Gregory , Lucas Sophie , Boon Thierry 
Published: March 2007

AbstractWe reported previously that the mouse tumor P815 expresses four distinct antigens (A, B, C, D) recognized by syngeneic cytolytic T lymphocytes (CTL). A fifth P815 antigen (E) was identified by means of a CTL clone derived from tumor‐infiltrating lymphocytes. We compared a number of mice for the orientation of their CTL response with respect to the various P815 antigens. Lymphocytes from mice inoculated subcutaneously with living P815 cells were stimulated in vitro with tumor cells and the resulting CTL were tested against targets expressing either antigens A and B or antigens C, D and E. Many mice had an asymmetrical response, some producing CTL directed almost exclusively against antigens A, B and others producing CTL directed almost exclusively against C, D. E. When mice were inoculated into two separate sites, different orientations in the responses of the two local lymph nodes were often observed, suggesting that individual differences in the orientation of the anti‐P815 CTL response do not result from preexisting differences between the animals. Asymmetrical CTL responses persisted in mice that were given a second injection of tumor cells. A possible interpretation of our results is that the major component of the CTL response is made of the progeny of a very small number of CTL precursors that happen to be the first to be stimulated by the tumor antigens.
Involvement of interleukin (IL)‐13, but not IL‐4, in spontaneous IgE and IgG4 production in nephrotic syndrome
Authors: Kimata Hajime , Fujimoto Masayuki , Furusho Kenshi 
Published: March 2007

AbstractNephrotic syndrome (NS) is a renal disease characterized by proteinuria and hypoalbuminemia. In NS patients without any allergic disease, serum IgE and IgG4 levels were selectively increased, and peripheral blood mononuclear cells (MNC) spontaneously produced IgE and IgG4. T cells produced interleukin (IL)‐13 spontaneously, and B cells constitutively expressed IL‐13 receptors (IL‐13R). In addition, T cells stimulated surface IgE‐negative (sIgE−) and sIgG4− B cells to produce IgE and IgG4, respectively, and IgE and IgG4 production was specifically blocked by anti‐IL‐13 antibody (Ab). MNC from atopic dermatitis (AD) patients also produced IgE and IgG4 spontaneously. However, in AD patients, T cells spontaneously produced IL‐4, but not IL‐13, and B cells constitutively expressed IL‐4R, but not IL‐13R. T cells stimulated sIgE− and sIgG4− B cells to produce IgE and IgG4, respectively, and the production was specifically blocked by anti‐IL‐4 Ab. On the other hand, sIgE+ and sIgG4+ B cells from both NS and AD patients spontaneously produced IgE and IgG4, respectively, and this production was not affected by T cells, anti‐IL‐4 Ab, or anti‐IL‐13 Ab. These results indicate that IL‐13 is involved in the enhanced production of IgE and IgG4 in NS, while IL‐4 is involved in these responses in AD.
Emergence in Cx knockout mice of a diverse cytotoxic T lymphocyte repertoire that recognizes a single peptide from the immunoglobulin constant x light chain region
Authors: Rueff‐Juy Dominique , Sanchez Pierre , Faure Mathias , Drapier Anne‐Marie , Cazenave Pierre‐André 
Published: March 2007

AbstractAllotype‐ or idiotype‐specific CD4+ T cells have been reported to recognize immunoglobulin (Ig) peptides presented by class II molecules. In contrast, few data are available concerning the generation of Ig peptide‐specific CD8+ T cells. We have therefore investigated whether T‐depleted spleen cells from Ig x light chain‐expressing 129/Sv mice (129x+/+) could induce, in Cx knockout mice (129 x−/−), the generation of Ig constant x light chain region (Cx)‐specific cytotoxic T lymphocytes (CTL). The determination of TCRβ chain expressed by nine CTL clones, together with the use of a library of overlapping peptides spanning the whole Cx sequence, show that the B cells from x+/+ mice are able to elicit in Cx knockout mice, the emergence of a diverse CTL repertoire that recognizes one single Cx peptide presented by the H‐2Kb class I molecule. In addition, these data support the notion that B cells are able to process and present on their class I molecules, peptides generated from their own x light chains.
T cells with dual antigen specificity in T cell receptor transgenic mice rejecting allografts
Authors: Simpson Elizabeth , Chandler Phillip , Sponaas Anna , Millrain Margaret , Dyson P. Julian 
Published: March 2007

AbstractAllelic exclusion of T cell receptor (TCR) genes is incomplete: a significant percentage (10–30%) of normal human and mouse peripheral T cells express two surface TCR α chains, and a small percentage of peripheral human T cells have been reported to express two surface TCR β chains. A proportion of thymocytes in TCR transgenic mice rearrange endogenous T cell receptor genes, and peripheral T cells with two TCR α chains, transgenic and endogenous, have been reported. T cell clones with more than a single TCR heterodimer on their surface might be expected to show specificity for more than one cognate antigen: we report here a T cell clone with dual antigen specificity, isolated from an F5 TCR influenza nucleoprotein (NP 366–374/Db)‐specific transgenic female mouse which had rejected an H‐2‐matched male skin graft. It was selected in vitro by stimulation with male H‐2b spleen cells in the absence of the NP366–374 peptide but has specificity for both H‐Y/Db and NP366–374. This contrasted with the single NP366–374/Db specificity shown by a control clone isolated from a Rag1–/– F5 mouse. The dual antigen specificity was associated with the rearrangement of endogenous TCR genes and cell surface expression of these as well as the TCR transgene.
Altered CD40 ligand induction in tolerant T lymphocytes
Authors: Bowen Frank , Haluskey Joyce , Quill Helen 
Published: March 2007

AbstractCD40 ligand (CD40L) is a member of the tumor necrosis factor superfamily and is expressed on the surface of activated T lymphocytes. The interaction of CD40L with CD40 on B cells results in B cell activation, immunoglobulin (Ig) secretion and Ig class switching. To study anergy as a mechanism of murine CD4 T cell tolerance, we determined both in vivo and in vitro that CD3‐activated anergic cells are deficient in the ability to stimulate B cell proliferation, and that anergic cells are defective for the T cell receptor/CD3‐mediated induction of CD40L expression. These results have implications for the recruitment of B cell responses by anergic T cells in vivo.
Differential binding of human interleukin‐1 (IL‐1) receptor antagonist to natural and recombinant soluble and cellular IL‐1 type I receptors
Authors: Svenson Morten , Nedergaard Susanne , Heegaard Peter M. H. , Whisenand Teri D. , Arend William P. , Bendtzen Klaus 
Published: March 2007

AbstractA recently described factor, interleukin‐1 receptor antagonist binding factor (IL‐IraBF), in serum of normal individuals is immunologically related to the interleukin‐1 receptor type I (IL‐1RI). It is presumably a soluble form of the receptor that binds exclusively to interleukin‐1 receptor antagonist (IL‐1ra). Recombinant soluble human IL‐1RI expressed in COS cells (sIL‐1RI) consists of the extracellular part of the receptor and binds all three known IL‐1 species but preferentially to IL‐1ra. We further characterized the sizes and binding of IL‐1raBF and sIL‐1RI to IL‐1ra by polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate, ligand binding interference analyses, N‐glycosidase treatment, concanavalin A affinity chromatography, and with the use of monoclonal antibodies (mAb) to human recombinant IL‐1ra. We also evaluated the binding of IL‐1ra to cellular IL‐1RI on MRC5 fibroblasts and the interference afforded by the soluble receptors. The results show that the protein backbones of IL‐1raBF and sIL‐1RI are of similar size (≈ 35–40 kDa) and that there are differences in the glycosylation of the two molecules. These carbohydrates were necessary for optimal binding of both molecules to IL‐1ra. Both factors blocked binding of IL‐1ra to cellular IL‐1RI, as did mAb to IL‐1ra, but the sites on IL‐1ra which bound to the mAb, and to IL‐1raBF and sIL‐1RI, differed. We conclude that there are important differences between the natural and recombinant forms of soluble IL‐1RI and that IL‐1ra binds differently to these molecules and to cellular IL‐1RI.
Protective role of γ/δ T cells and α/β T cells in tuberculosis
Authors: Ladel Christoph H. , Blum Carmen , Dreher Anja , Reifenberg Kurt , Kaufmann Stefan H. E. 
Published: March 2007

AbstractTuberculosis is a chronic infectious disease which causes major health problems globally. Although acquired resistance crucially depends on α/β lymphocytes, circumstantial evidence suggests that, in addition, γ/δ T lymphocytes contribute to protection against tuberculosis. We have studied Mycobacterium tuberculosis infection in TcR‐δ‐/‐ or TcR‐β‐/‐ gene deletion mutants which completely lack γ/δ T cells or α/β T cells, respectively. Low inocula of M. tuberculosis led to death of TcR‐β‐/‐ mice and transient disease exacerbation in TcR‐δ‐/‐ mutants. Infection with higher inocula caused rapid death of TcR‐δ‐/‐ mice. The development of and bacterial containment in granulomatous lesions was markedly impaired in TcR‐β‐/‐, and less severly affected in TcR‐δ‐/‐ mutants. Mycobacteria‐induced IFN‐γ production by spleen cells in vitro was almost abolished in TcR‐β‐/‐ and virtually unaffected in TcR‐δ‐/‐ mice. Our data confirm the crucial role of α/β T cells in protection against established tuberculosis and formally prove a protective role of γ/δ T cells in early tuberculosis.
Oxpentifylline inhibits tumor necrosis factor‐α mRNA transcription and protects against arthritis in mercuric chloride‐treated Brown Norway rats
Authors: Kiely Patrick D. W. , Gillespie Kathleen M. , Oliveira David B. G. 
Published: March 2007

AbstractThe phosphodiesterase inhibitor oxpentifylline (OXP) has a number of potentially important immunomodulatory actions which include a selective inhibition of the Th1 subset of CD4+ cells in vitro and inhibition of tumor necrosis factor (TNF)‐α mRNA transcription. In vivo, it has a dramatic protective effect against experimental allergic encephalomyelitis. In this animal model, tissue injury is associated with both a Th1 response and with TNF‐α production, either of which could be targets for the protective action of OXP. In an attempt to clarify the relative importance of the Th cell subsets and TNF‐α in pathogenesis, we investigated the effect of OXP on a Th2 model of T cell‐dependent disease, mercuric chloride (HgCl2)‐induced autoimmunity in the Brown Norway rat. The effects of OXP on the Th1: Th2 response, TNF‐α mRNA transcription in spleen and ankle joints, and on the incidence and severity of arthritis and cecal vasculitis have been examined and the effects in vivo have been compared with those of a soluble TNF receptor‐IgG1 fusion protein (sTNFR) that neutralizes rat TNF‐α. In two separate experiments, OXP significantly enhanced unstimulated levels of splenic interleukin‐4 (IL‐4) mRNA (median 62 %, of an artificial IL‐4 mRNA construct, vs. 36.5 % in controls) and in one experiment, exaggerated the total IgE response to HgCl2. OXP inhibited HgCl2‐induced TNF‐α mRNA transcription in spleen and ankle joints. In three separate experiments, OXP had a significant protective effect against arthritis, with the mean incidence reduced from 100 % to 30 % and mean peak score reduced from 7.2 to 2.59 (experiments 1 and 2). The protection against arthritis was indistinguishable from that produced by sTNFR. There was no such protection against cecal vasculitis with either OXP or sTNFR. These results demonstrate that OXP induces a shift towards a Th2 response, inhibits TNF‐α mRNA transcription locally in joint and systemically in spleen, and has a protective effect against arthritis similar to that produced by sTNFR in the HgCl2‐treated BN rat. We conclude that TNF‐α is a critical cytokine in the pathogenesis of arthritis but not cecal vasculitis in this model, and that inhibition of TNF‐α transcription is the most important mode of action of OXP in this situation. OXP may be a potential therapeutic agent in the treatment of other arthritides, such as human rheumatoid arthritis, in which TNF‐α has been implicated in pathogenesis.
Ligation of either CD2 or CD28 rescues CD4+ T cells from HIV‐gp120‐induced apoptosis
Authors: Tuosto Loretta , Piazza Cinzia , Moretti Simona , Modesti Andrea , Greenlaw Roseanna , Lechler Robert , Lombardi Giovanna , Piccolella Enza 
Published: March 2007

AbstractTemporal or quantitative imbalance in signals delivered to T cells via T cell antigen receptor (TCR), the CD4 co‐receptor, and accessory molecules can lead to anergy, apoptosis, or both. This has been observed following ligation of CD4 by HIV gp120 prior to TCR occupancy. The ability of molecules such as CD2 and CD28, interacting with their ligands LFA‐3 and B7, to provide signals that protect T cells from the induction of anergy, has been reported. Here, we demonstrate that ligation of CD2 and CD28 in conjunction with TCR occupancy rescue T cells that have been programmed for apoptotic death by prior CD4 ligation to gp120. This appears to be the result of augmented interleukin‐2 and interleukin‐4 release by the T cells following these molecular interactions. In conclusion, our results suggest that an impairment of antigen‐presenting accessory cell functions could favor gp120‐mediated apoptosis in HIV‐uninfected cells.
Listeriolysin generates a route for the presentation of exogenous antigens by major histocompatibility complex class I
Authors: Darji Ayub , Chakraborty Trinad , Wehland Jürgen , Weiss Siegfried 
Published: March 2007

AbstractWe have exploited the pore forming activity of listeriolysin, the hemolysin of Listeria monocytogenes, to activate CD8+ T cells with soluble proteins in vivo and in vitro. Immunization with soluble, hemolytically active listeriolysin induces both cytotoxic CD8+ T cells and CD4+ T cells, and the CD8+ T cells can be propagated with soluble listeriolysin in vitro. Moreover, conventional antigens like ovalbumin mixed together with listeriolysin are also efficiently introduced into the MHC class I pathway in vitro and in vivo. Hence, listeriolysin effectively directs itself and passenger molecules into the intracellular compartment that leads to the cytotoxic T cell response. In this way, we circumvent the bias of CD8+ T cells to recognize intracellular antigens presented by major histocompatibility complex class I molecules. As cytotoxic CD8+ T cells are of pivotal importance in eliminating viral and microbial pathogens, the findings reported here could prove to be useful in vaccine development.
Specific binding of Fyn and phosphatidylinositol 3‐kinase to the B cell surface glycoprotein CD19 through their src homology 2 domains
Authors: Chalupny N. Jan , Aruffo Alejandro , Esselstyn James M. , Chan Po‐Ying , Bajorath Jürgen , Blake James , Gilliland Lisa K. , Ledbetter Jeffrey A. , Tepper Mark A. 
Published: March 2007

AbstractCD 19 is a B cell surface protein capable of forming non‐covalent molecular complexes with a number of other B cell surface proteins including the CD21/CD81/Leu‐13 complex as well as with surface immunoglobulin. CD19 tyrosine phosphorylation increases after B cell activation, and is proposed to play a role in signal transduction through its cytoplasmic domain, which contains nine tyrosine residues. Several second messenger proteins have been shown to immunoprecipitate with CD 19, including p59 Fyn (Fyn), p59 Lyn (Lyn) and phosphatidylinositol‐3 kinase (PI‐3 kinase). These associations are predicted to occur via the src‐homology 2 (SH2) domains of the second messenger proteins. Two of the cytoplasmic tyrosines in the CD 19 cytoplasmic region contain the consensus binding sequence for the PI‐3 kinase SH2 domain (YPO4‐X‐X‐M). However, the reported consensus binding sequence for the Fyn and Lyn SH2 domains (YPO4‐X‐X‐I/L) is not found in CD 19. We investigated the capacity of CD 19 cytoplasmic tyrosines to bind both Fyn and PI‐3 kinase SH2‐domain fusion proteins. In activated B cells, both Fyn and PI‐3 kinase SH2‐domain fusion proteins precipitate CD 19. Using synthetic tyrosine‐phosphorylated peptides comprising each of the CD 19 cytoplasmic tyrosines and surrounding amino acids, we investigated the ability of the Fyn SH2 and PI‐3 kinase SH2 fusion proteins to bind to the different CD 19 cytoplasmic phosphotyrosine peptides. ELISA revealed that the two CD 19 cytoplasmic tyrosine residues contained within the Y‐X‐X‐M sequences (Y484 and Y515) bound preferentially to the PI‐3 kinase SH2‐domain fusion proteins. Two different tyrosines (Y405 and Y445) bound preferentially to the Fyn SH2‐domain fusion protein via a novel sequence, Y‐E‐N‐D/E, different from that previously reported for the Fyn SH2 domain. In precipitation studies, peptide Y484 was able to compete with tyrosine phosphorylated CD 19 specifically for binding to the PI‐3 kinase SH2 domain fusion proteins, while peptides Y405 and Y445 were able to compete specifically for binding to the Fyn SH2 domain fusion proteins. These results indicate that CD19 may be capable of binding both Fyn and PI‐3 kinase concurrently, suggesting a mechanism for CD 19 signal transduction, in which binding of PI‐3 kinase to the Fyn SH3 domain results in activation of PI‐3 kinase.