bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intraallograft Chemokine RNA and Protein During Rejection of MHC-Matched/Multiple Minor Histocompatibility-Disparate Skin Grafts
Authors: Watarai Yoshihiko , Koga Shoji , Paolone David R. , Engeman Tara M. , Tannenbaum Charles , Hamilton Thomas A. , Fairchild Robert L. 
Published: April 2014

AbstractChemokines direct leukocyte recruitment into sites of tissue inflammation and may facilitate recruitment of leukocytes into allografts following transplantation. Although the expression of chemokines during rejection of MHC-disparate allografts has been examined, chemokine expression in MHC-matched/multiple minor histocompatibility Ag-disparate allografts has not been tested. The intraallograft RNA expression of several C-X-C and C-C chemokines was tested during rejection of full thickness skin grafts from B10.D2 donors on control Ig-, anti-CD4 mAb-, and anti-CD8 mAb-treated BALB/c recipients. In all recipients, two patterns of intragraft chemokine expression were observed during rejection of these grafts: 1) macrophage-inflammatory protein-1α, macrophage-inflammatory protein-1β, GRO-α (KC), JE, and IFN-γ-inducible protein (IP-10) were expressed at equivalent levels in allo- and isografts for 2–4 days posttransplant and then returned to low or undetectable levels; and 2) IP-10 and monokine induced by IFN-γ (Mig) were expressed in the allografts 3 days before rejection was completed, suggesting a possible role in recruiting primed T cells into the allograft. Three days before completion of rejection, intraallograft IP-10 protein was restricted to the epidermis, whereas Mig was located in the lower dermis and associated with the intense infiltration of mononuclear cells. Treatment of B10.D2 recipients with rabbit antiserum to Mig, but not to IP-10, delayed rejection of the allografts 3–4 days. The results suggest that Mig mediates optimal recruitment of T cells into MHC-matched/multiple minor histocompatibility Ag-disparate allografts during rejection.
Cutting Edge: CD46, a New Costimulatory Molecule for T Cells, That Induces p120CBL and LAT Phosphorylation
Authors: Astier Anne , Trescol-Biémont Marie-Claude , Azocar Olga , Lamouille Barbara , Rabourdin-Combe Chantal 
Published: April 2014

Abstract
The widely expressed transmembrane molecule CD46 is the complement regulatory receptor for C3b as well as the receptor for several pathogens. Beside its binding functions, CD46 is also able to transduce signals. We showed that CD46 aggregation on human T cells induces p120CBL and linker for activation of T cells (LAT) phosphorylation. These two proteins are adaptor proteins known to regulate TCR signaling. p120CBL is a complex adaptor protein involved in negatively regulating signaling events, whereas LAT is a transmembrane adaptor protein found in glycolipid-enriched microdomains essential for T cell activation. Therefore, we investigated if a CD46/TCR costimulation would affect T cell activation. Indeed, CD46/CD3 costimulation strongly promotes T cell proliferation. Therefore, we propose that CD46 acts as a potent costimulatory molecule for human T cells.
Competition for Specific Intrathymic Ligands Limits Positive Selection in a TCR Transgenic Model of CD4+ T Cell Development
Authors: Wong Phillip , Goldrath Ananda W. , Rudensky Alexander Y. 
Published: April 2014

AbstractEfficient positive selection of a broad repertoire of T cells is dependent on the presentation of a diverse array of endogenous peptides on MHC molecules in the thymus. It is unclear, however, whether the development of individual TCR specificities is influenced by the abundance of their selecting ligands. To examine this, we analyzed positive selection in a transgenic mouse carrying a TCR specific for the human CLIP:I-Ab class II complex. We found that these mice exhibit significantly reduced CD4+ T cell development compared with two other transgenic mice carrying TCRs selected on I-Ab. Moreover, many of the selected cells in these mice express endogenous and transgenic receptors as a consequence of dual TCRα expression. Dramatic enhancement of the selection efficiency is observed, however, when fewer transgenic cells populate the thymus in mixed bone marrow chimeras. These results suggest that positive selection is limited by the availability of selecting peptides in the thymus. This becomes apparent when large numbers of thymocytes compete for such peptides in TCR transgenic animals. Under such conditions, thymocytes appear to undergo further TCRα gene rearrangement to produce a receptor that may be selected more efficiently by other thymic self-peptides.
Regulation of Encephalitogenic T Cells with Recombinant TCR Ligands
Authors: Burrows Gregory G. , Adlard Kirsten L. , Bebo Bruce F. , Chang Justin W. , Tenditnyy Kirill , Vandenbark Arthur A. , Offner Halina 
Published: April 2014

AbstractWe have previously described recombinant MHC class II β1 and α1 domains loaded with free antigenic peptides with potent inhibitory activity on encephalitogenic T cells. We have now produced single-chain constructs in which the peptide Ag is genetically encoded within the same exon as the linked β1 and α1 domains, overcoming the problem of displacement of peptide Ag from the peptide binding cleft. We here describe clinical effects of recombinant TCR ligands (RTLs) comprised of the rat RT1.B β1α1 domains covalently linked to the 72–89 peptide of guinea pig myelin basic protein (RTL-201), to the corresponding 72–89 peptide from rat myelin basic protein (RTL-200), or to cardiac myosin peptide CM-2 (RTL-203). Only RTL-201 possessed the ability to prevent and treat active or passive experimental autoimmune encephalomyelitis. Amelioration of experimental autoimmune encephalomyelitis was associated with a selective inhibition of proliferation response and cytokine production by Ag-stimulated lymph node T cells and a drastic reduction in the number of encephalitogenic and recruited inflammatory cells infiltrating the CNS. The exquisitely selective inhibition could be observed between molecules that differ by a single methyl group (the single amino acid residue difference between RTL-200 (threonine) and RTL-201 (serine) at position 80 of the myelin basic protein peptide). These novel RTLs provide a platform for developing potent and selective human diagnostic and therapeutic agents for treatment of autoimmune disease.
A New Small Molecule C5a Receptor Antagonist Inhibits the Reverse-Passive Arthus Reaction and Endotoxic Shock in Rats
Authors: Strachan Anna J. , Woodruff Trent M. , Haaima Gerald , Fairlie David P. , Taylor Stephen M. 
Published: April 2014

AbstractC5a is implicated as a pathogenic factor in a wide range of immunoinflammatory diseases, including sepsis and immune complex disease. Agents that antagonize the effects of C5a could be useful in these diseases. We have developed some novel C5a antagonists and have determined the acute anti-inflammatory properties of a new small molecule C5a receptor antagonist against C5a- and LPS-induced neutrophil adhesion and cytokine expression, as well as against some hallmarks of the reverse Arthus reaction in rats. We found that a single i.v. dose (1 mg/kg) of this antagonist inhibited both C5a- and LPS-induced neutropenia and elevated levels of circulating TNF-α, as well as polymorphonuclear leukocyte migration, increased TNF-α levels and vascular leakage at the site of immune complex deposition. These results indicate potent anti-inflammatory activities of a new C5a receptor antagonist and provide more evidence for a key early role for C5a in sepsis and the reverse Arthus reaction. The results support a role for antagonists of C5a receptors in the therapeutic intervention of immunoinflammatory disease states such as sepsis and immune complex disease.
Ro60 Peptides Induce Antibodies to Similar Epitopes Shared Among Lupus-Related Autoantigens
Authors: Deshmukh Umesh S. , Lewis Janet E. , Gaskin Felicia , Dhakephalkar Prashant K. , Kannapell Carol C. , Waters Samuel T. , Fu Shu Man 
Published: April 2014

AbstractThe coexistence of autoantibodies to ribonucleoproteins (RNP) in sera of patients with systemic lupus erythematosus has been attributed to intermolecular determinant spreading among physically associated proteins. Recently, we showed that murine Ab responses to rRo60 or Ro60 peptides were diversified unexpectedly to small nuclear RNP. In this investigation, the mechanisms for this autoantibody diversification were examined. Intramolecular determinant spreading was demonstrated in mice immunized with human or mouse Ro60316–335. Immune sera depleted of anti-peptide Ab immunoprecipitated Ro60-associated mY1 and mY3 RNA and remained reactive to a determinant on Ro60128–285. Absorption with the immunogen depleted the immune sera completely of anti-Golgi complex Ab (inducible only with human Ro60316–335) and anti-La Ab, and reduced substantially Ab to SmD and 70-kDa U1RNP. Mouse rRo60 completely inhibited the immune sera reactivity to La, SmD, and 70-kDa U1RNP. However, La, SmD, and 70-kDa U1RNP preferentially inhibited the antiserum reactivities to these Ags, respectively. Affinity-purified anti-La Ab were reactive with Ro60, La, SmD, and 70-kDa U1RNP. These results provide evidence that a population of the induced autoantibodies recognized determinants shared by these autoantigens. Lack of sequence homology between Ro60316–335 and La, SmD, or 70-kDa U1RNP suggests that these determinants are conformational. Interestingly, similar cross-reactive autoantibodies were found in NZB/NZW F1 sera. Thus, a single molecular mimic may generate Ab to multiple RNP Ags. Furthermore, cross-reactive determinants shared between antigenic systems that are not associated physically (Ro/La RNP and small nuclear RNP) may be important in the generation of autoantibody diversity in systemic lupus erythematosus.
Differential Ca2+ Influx, KCa Channel Activity, and Ca2+ Clearance Distinguish Th1 and Th2 Lymphocytes
Authors: Fanger Christopher M. , Neben Amber L. , Cahalan Michael D. 
Published: April 2014

Abstract
In Th1 and Th2 lymphocytes, activation begins with identical stimuli but results in the production of different cytokines. The expression of some cytokine genes is differentially induced according to the amplitude and pattern of Ca2+ signaling. Using fura- 2 Ca2+ imaging of murine Th1 and Th2 clones, we observed that the Ca2+ rise elicited following store depletion with thapsigargin is significantly lower in Th2 cells than in Th1 cells. Maximal Ca2+ influx rates and whole-cell Ca2+ currents showed that both Th1 and Th2 cells express indistinguishable Ca2+-release-activated Ca2+ channels. Therefore, we investigated other mechanisms controlling the concentration of intracellular Ca2+, including K+ channels and Ca2+ clearance from the cytosol. Whole-cell recording demonstrated that there is no distinction in the amplitudes of voltage-gated K+ currents in the two cell types. Ca2+-activated K+ (KCa) currents, however, were significantly smaller in Th2 cells than in Th1 cells. Pharmacological equalization of Ca2+-activated K+ currents in the two cell types reduced but did not completely eliminate the difference between Th1 and Th2 Ca2+ responses, suggesting divergence in an additional Ca2+ regulatory mechanism. Therefore, we analyzed Ca2+ clearance from the cytosol of both cell types and found that Th2 cells extrude Ca2+ more quickly than Th1 cells. The combination of a faster Ca2+ clearance mechanism and smaller Ca2+-activated K+ currents in Th2 cells accounts for the lower Ca2+ response of Th2 cells compared with Th1 cells.
Tumors Promote Altered Maturation and Early Apoptosis of Monocyte-Derived Dendritic Cells
Authors: Kiertscher Sylvia M. , Luo Jie , Dubinett Steven M. , Roth Michael D. 
Published: April 2014

Abstract
Tumors produce a number of immunosuppressive factors that block the maturation of CD34+ stem cells into dendritic cells (DC). We hypothesized that tumors might also interfere with the maturation and/or function of human monocyte-derived DC. In contrast to stem cells, we found that CD14+ cells responded to tumor culture supernatant (TSN) by increasing expression of APC surface markers, up-regulating nuclear translocation of RelB, and developing allostimulatory activity. Although displaying these characteristics of mature DC, TSN-exposed DC lacked the capacity to produce IL-12, did not acquire full allostimulatory activity, and rapidly underwent apoptosis. The effects of TSN appeared to be specific for maturing DC, and were not reversed by Abs against known DC regulatory factors including IL-10, vascular endothelial growth factor, TGF-β, or PGE2. Supernatants collected from nonmalignant cell sources had no effect on DC maturation. The altered maturation and early apoptosis of monocyte-derived DC may represent another mechanism by which tumors evade immune detection.
Positive Regulation of c-Jun N-Terminal Kinase and TNF-α Production But Not Histamine Release by SHP-1 in RBL-2H3 Mast Cells
Authors: Xie Zhi-Hui , Zhang Juan , Siraganian Reuben P. 
Published: April 2014

AbstractThe SH2-containing protein tyrosine phosphatase1 (SHP-1) is important for signaling from immune receptors. To investigate the role of SHP-1 in mast cells we overexpressed the wild-type and the phosphatase-inactive forms of SHP-1 in rat basophilic leukemia 2H3 (RBL-2H3) mast cell line. The phosphatase-inactive SHP-1 (C453S or D419A) retains its ability to bind tyrosine phosphorylated substrates and thereby competes with the endogenous wild-type enzyme. Overexpression of wild-type SHP-1 decreased the FcεRI aggregation-induced tyrosine phosphorylation of the β and γ subunits of the receptor whereas the dominant negative SHP-1 enhanced phosphorylation. There were also similar changes in the tyrosine phosphorylation of Syk. However, receptor-induced histamine release in the cells expressing either wild-type or dominant negative SHP-1 was similar to that in the parental control cells. In contrast, compared with the parental RBL-2H3 cells, FcεRI-induced c-Jun N-terminal kinase phosphorylation and the level of TNF-α mRNA was increased in the cells overexpressing wild-type SHP-1 whereas the dominant negative SHP-1 had the opposite effect. The substrate-trapping mutant SHP1/D419A identified pp25 and pp30 as two major potential substrates of SHP-1 in RBL-2H3 cells. Therefore, SHP-1 may play a role in allergy and inflammation by regulating mast cell cytokine production.
NF-κB Modulates TNF-α Production by Alveolar Macrophages in Asymptomatic HIV-Seropositive Individuals
Authors: Mathys Jean-Marie , Melanson Suzanne M. , Schiffer-Alberts Deborah J. , Ioannidis John P. A. , Koziel Henry , Skolnik Paul R. 
Published: April 2014

Abstract
Local TNF-α production in different organs may affect HIV replication and pathogenesis. Alveolar macrophages (AMs) obtained by bronchoalveolar lavage from asymptomatic HIV-seropositive and HIV-seronegative individuals did not spontaneously release TNF-α, but LPS stimulation of these cells significantly increased TNF-α production. We tested whether NF-κB affects TNF-α production by AMs using N-tosyl-l-phenylalanine chloromethylketone (TPCK) or N-benzoyl-l-tyrosine ethyl ester (BTEE), which inhibit the degradation of IκB, or tricyclodecan-9-yl-xanthogenate-potassium (D609), which inhibits phospholipase C. Alveolar macrophages were exposed to LPS alone and with the chemical protease inhibitors TPCK, BTEE, and D609. NF-κB DNA binding induced by LPS treatment of AMs was inhibited by TPCK, BTEE, and D609. These agents also inhibited TNF-α mRNA and TNF-α protein production. After 24 h, the levels of TNF-α mRNA reached equilibrium, as assessed by RT-PCR. The levels of NF-κB mRNA remained constant under all conditions. The levels of IκB-α mRNA were similar after 30, 60, and 180 min, but the IκB-β mRNA concentration was initially low and increased over time under all conditions. IκB-α and IκB-β protein production was not affected by the chemical protease inhibitors. Our data show that TNF-α production by LPS-stimulated AMs from asymptomatic HIV-seropositive and -seronegative individuals is regulated via the phospholipase C pathway and by NF-κB DNA binding activity without obvious changes in IκB-α or IκB-β protein concentrations.
Delineation of a CpG Phosphorothioate Oligodeoxynucleotide for Activating Primate Immune Responses In Vitro and In Vivo
Authors: Hartmann Gunther , Weeratna Risini D. , Ballas Zuhair K. , Payette Paul , Blackwell Sue , Suparto Irma , Rasmussen Wendy L. , Waldschmidt Marianella , Sajuthi Dondin , Purcell Robert H. , Davis Heather L. , Krieg Arthur M. 
Published: April 2014

AbstractOligodeoxynucleotides (ODN) containing unmethylated CpG dinucleotides within specific sequence contexts (CpG motifs) are detected, like bacterial or viral DNA, as a danger signal by the vertebrate immune system. CpG ODN synthesized with a nuclease-resistant phosphorothioate backbone have been shown to be potent Th1-directed adjuvants in mice, but these motifs have been relatively inactive on primate leukocytes in vitro. Moreover, in vitro assays that predict in vivo adjuvant activity for primates have not been reported. In the present study we tested a panel of CpG ODN for their in vitro and in vivo immune effects in mice and identified in vitro activation of B and NK cells as excellent predictors of in vivo adjuvant activity. Therefore, we tested &gt;250 phosphorothioate ODN for their capacity to stimulate proliferation and CD86 expression of human B cells and to induce lytic activity and CD69 expression of human NK cells. These studies revealed that the sequence, number, and spacing of individual CpG motifs contribute to the immunostimulatory activity of a CpG phosphorothioate ODN. An ODN with a TpC dinucleotide at the 5′ end followed by three 6 mer CpG motifs (5′-GTCGTT-3′) separated by TpT dinucleotides consistently showed the highest activity for human, chimpanzee, and rhesus monkey leukocytes. Chimpanzees or monkeys vaccinated once against hepatitis B with this CpG ODN adjuvant developed 15 times higher anti-hepatitis B Ab titers than those receiving vaccine alone. In conclusion, we report an optimal human CpG motif for phosphorothioate ODN that is a candidate human vaccine adjuvant.
MEK Activity Regulates Negative Selection of Immature CD4+CD8+ Thymocytes
Authors: Bommhardt Ursula , Scheuring Yvonne , Bickel Chrisitan , Zamoyska Rose , Hünig Thomas 
Published: April 2014

Abstract
CD4+CD8+ thymocytes are either positively selected and subsequently mature to CD4 single positive (SP) or CD8 SP T cells, or they die by apoptosis due to neglect or negative selection. This clonal selection is essential for establishing a functional self-restricted T cell repertoire. Intracellular signals through the three known mitogen-activated protein (MAP) kinase pathways have been shown to selectively guide positive or negative selection. Whereas the c-Jun N-terminal kinase and p38 MAP kinase regulate negative selection of thymocytes, the extracellular signal-regulated kinase (ERK) pathway is required for positive selection and T cell lineage commitment. In this paper, we show that the MAP/ERK kinase (MEK)-ERK pathway is also involved in negative selection. Thymocytes from newborn TCR transgenic mice were cultured with TCR/CD3ε-specific Abs or TCR-specific agonist peptides to induce negative selection. In the presence of the MEK-specific pharmacological inhibitors PD98059 or UO126, cell recovery was enhanced and deletion of DP thymocytes was drastically reduced. Furthermore, development of CD4 SP T cells was blocked, but differentiation of mature CD8 SP T cells proceeded in the presence of agonist peptides when MEK activity was blocked. Thus, our data indicate that the outcome between positively and negatively selecting signals is critically dependent on MEK activity.
The Density of Peptides Displayed by Dendritic Cells Affects Immune Responses to Human Tyrosinase and gp100 in HLA-A2 Transgenic Mice
Authors: Bullock Timothy N. J. , Colella Teresa A. , Engelhard Victor H. 
Published: April 2014

AbstractSeveral HLA-A*0201-restricted peptide epitopes that can be used as targets for active immunotherapy have been identified within melanocyte differentiation proteins. However, uncertainty exists as to the most effective way to elicit CD8+ T cells with these epitopes in vivo. We report the use of transgenic mice expressing a derivative of HLA-A*0201, and dendritic cells, to enhance the activation of CD8+ T cells that recognize peptide epitopes derived from human tyrosinase and glycoprotein 100. We find that by altering the cell surface density of the immunizing peptide on the dendritic cells, either by pulsing with higher concentrations of peptide, or by changing the MHC-peptide-binding affinity by generating variants of the parent peptides, the size of the activated CD8+ T cell populations can be modulated in vivo. Significantly, the density of peptide that produced the largest response was less than the maximum density achievable through short-term peptide pulsing. We have also found, however, that while some variant peptides are effective at eliciting both primary and recall CD8+ T cell responses that can recognize the parental epitope, other variant epitopes lead to the outgrowth of CD8+ T cells that only recognize the variant. HLA-A*0201 transgenic mice provide an important model to define which peptide variants are most likely to stimulate CD8+ T cell populations that recognize the parental, melanoma-specific peptide.
Sensitivity Difference to the Suppressive Effect of Prostaglandin E2 Among Mouse Strains: A Possible Mechanism to Polarize Th2 Type Response in BALB/c Mice
Authors: Kuroda Etsushi , Sugiura Tsutomu , Zeki Kazuya , Yoshida Yasuhiro , Yamashita Uki 
Published: April 2014

AbstractPGE2 has been shown to play a prominent role in regulating Th1 and Th2 type responses. We studied the role of PGE2 in IFN-γ production by Staphylococcus aureus Cowan I-stimulated spleen cells from several mouse strains such as BALB/c, C3H/HeN, and C57BL/6. When spleen cells were pretreated with indomethacin (cyclooxygenase (COX)-1 and COX-2 inhibitor) or NS-398 (COX-2-specific inhibitor), S. aureus Cowan I -induced IFN-γ production was increased more markedly in spleen cells from BALB/c mice than from C3H/HeN and C57BL/6 mouse. However, PGE2 production was not significantly different among spleen cells from three mouse strains. When various concentrations of PGE2 were exogeneously added to spleen cells, PGE2 showed a stronger suppressive effect on IFN-γ production in spleen cells from BALB/c mice than from other strains of mice. This suppressive effect of PGE2 in BALB/c mice mainly depended on IL-12p70 production by APCs. More PGE2 binding sites were found in BALB/c spleen cells than in C3H/HeN spleen cells, indicating that the sensitivity difference to the suppressive effect of PGE2 was due to the difference of the number of PGE2 receptors. The administration of NS-398 into BALB/c mice enhanced Ag-specific IFN-γ production, but not IL-4 production. This effect is the same as IL-12 administration in vivo. From these results, we propose that the modulation of PGE2 is important for Th1 activation via IFN-γ and IL-12p70 production in vitro and in vivo and that PGE2 is one of the pivotal factors in the Th2-dominant immune response in BALB/c mice.