bluuebunny/crossref_metadata_2025_split huggingface dataset:
Src Homology 2 Domain-Containing Protein-Tyrosine Phosphatases, SHP-1 and SHP-2, Are Required for Platelet Endothelial Cell Adhesion Molecule-1/CD31-Mediated Inhibitory Signaling
Authors: Henshall Tanya L. , Jones Karen L. , Wilkinson Ray , Jackson Denise E. 
Published: April 2014

AbstractPlatelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) is a newly assigned member of the Ig immunoreceptor tyrosine-based inhibitory motif superfamily, and its functional role is suggested to be an inhibitory receptor that modulates immunoreceptor tyrosine-based activation motif-dependent signaling cascades. To test whether PECAM-1 is capable of delivering inhibitory signals in B cells and the functional requirement of protein-tyrosine phosphatases (PTPs) for this inhibitory signaling, we generated chimeric FcγRIIB1-PECAM-1 receptors containing the extracellular and transmembrane portions of murine FcγRIIB1 and the cytoplasmic domain of human PECAM-1. These chimeric receptors were stably expressed in chicken DT40 B cells either as wild-type or mutant cells deficient in SHP-1−/−, SHP-2−/−, SHIP−/−, or SHP-1/2−/− and then assessed for their ability to inhibit B cell Ag receptor (BCR) signaling. Coligation of wild-type FcγRIIB1-PECAM-1 with BCR resulted in inhibition of intracellular calcium release, suggesting that the cytoplasmic domain of PECAM-1 is capable of delivering an inhibitory signal that blocks BCR-mediated activation. This PECAM-1-mediated inhibitory signaling correlated with tyrosine phosphorylation of the FcγRIIB1-PECAM-1 chimera, recruitment of SHP-1 and SHP-2 PTPs by the phosphorylated chimera, and attenuation of calcium mobilization responses. Mutational analysis of the two tyrosine residues, 663 and 686, constituting the immunoreceptor tyrosine-based inhibitory motifs in PECAM-1 revealed that both tyrosine residues play a crucial role in the inhibitory signal. Functional analysis of various PTP-deficient DT40 B cell lines stably expressing wild-type chimeric FcγRIIB1-PECAM-1 receptor indicated that cytoplasmic Src homology 2-domain-containing phosphatases, SHP-1 and SHP-2, were both necessary and sufficient to deliver inhibitory negative regulation upon coligation of BCR complex with inhibitory receptor.
Oral Tolerance Revisited: Prior Oral Tolerization Abrogates Cholera Toxin-Induced Mucosal IgA Responses
Authors: Kato Hirotomo , Fujihashi Kohtaro , Kato Rie , Yuki Yoshikazu , McGhee Jerry R. 
Published: April 2014

AbstractOral delivery of a large dose or prolonged feeding of protein Ags induce systemic unresponsiveness most often characterized as reduced IgG and IgE Ab- and Ag-specific CD4+ T cell responses. It remains controversial whether oral tolerance extends to diminished mucosal IgA responses in the gastrointestinal tract. To address this issue, mice were given a high oral dose of OVA or PBS and then orally immunized with OVA and cholera toxin as mucosal adjuvant, and both systemic and mucosal immune responses were assessed. OVA-specific serum IgG and IgA and mucosal IgA Ab levels were markedly reduced in mice given OVA orally compared with mice fed PBS. Furthermore, when OVA-specific Ab-forming cells (AFCs) in both systemic and mucosa-associated tissues were examined, IgG AFCs in the spleen and IgA AFCs in the gastrointestinal tract lamina propria of mice given OVA orally were dramatically decreased. Furthermore, marked reductions in OVA-specific CD4+ T cell proliferative and cytokine responses in spleen and Peyer’s patches were seen in mice given oral OVA but were unaffected in PBS-fed mice. We conclude that high oral doses of protein induce both mucosal and systemic unresponsiveness and that use of mucosal adjuvants that induce both parenteral and mucosal immunity may be a better way to assess oral tolerance.
Antigen Receptor Proximal Signaling in Splenic B-2 Cell Subsets
Authors: Li Xiaoli , Martin Flavius , Oliver Alyce M. , Kearney John F. , Carter Robert H. 
Published: April 2014

AbstractSplenic marginal zone (MZ) and follicular mantle (FO) B cells differ in their responses to stimuli in vitro and in vivo. We have previously shown that MZ cells exhibit greater calcium responses after ligation of membrane IgM (mIgM). We have now investigated the molecular mechanism underlying the difference in calcium responses following ligation of mIgM and studied the response to total B cell receptor ligation in these two subsets. We compared key cellular proteins involved in calcium signaling in MZ and FO cells. Tyrosine phosphorylation and activity of phospholipase C-γ2 and Syk protein tyrosine kinase were significantly higher in MZ cells than in FO cells after mIgM engagement, providing a likely explanation for our previous findings. Tyrosine phosphorylation of CD22 and expression of Src homology 2-containing inositol phosphatase and Src homology 2-containing protein tyrosine phosphatase-1 were also higher in the MZ cells. Expression and tyrosine phosphorylation of Btk, BLNK, Vav, or phosphatidylinositol 3-kinase were equivalent. In contrast, stimulation with anti-κ induced equivalent increases in calcium and activation of Syk in the two subsets. These signals were also equivalent in cells from IgM transgenic, JH knockout mice, which have equivalent levels of IgM in both subsets. With total spleen B cells, Btk was maximally phosphorylated at a lower concentration of anti-κ than Syk. Thus, calcium signaling in the subsets of mature B cells reflects the amount of Ig ligated more than the isotype or the subset and this correlates with the relative tyrosine phosphorylation of Syk.
Ligation of 4-1BB (CDw137) Regulates Graft-Versus-Host Disease, Graft-Versus-Leukemia, and Graft Rejection in Allogeneic Bone Marrow Transplant Recipients
Authors: Blazar Bruce R. , Kwon Byoung S. , Panoskaltsis-Mortari Angela , Kwak Kyu B. , Peschon Jacques J. , Taylor Patricia A. 
Published: April 2014

Abstract4-1BB is expressed on activated CD4+ and CD8+ T cells; its ligand, 4-1BB ligand is expressed on APCs. Despite expression on both T cell subpopulations, 4-1BB has been reported to predominantly affect CD8+ T cell responses. By quantifying graft-vs-host disease alloresponses in vivo, we demonstrate that both CD4+ and CD8+ T cell-mediated alloresponses are regulated by 4-1BB/4-1BB ligand interactions to approximately the same extent. 4-1BB receptor-facilitated CD4+ T cell-mediated alloresponses were partly CD28 independent. In two distinct marrow graft rejection systems, host CD8+ and CD4+ T cells each separately contributed to host anti-donor T cell-mediated allograft rejection. α4-1BB mAb increased the graft-vs-leukemia effect of a suboptimal number of donor splenocytes given later post bone marrow transplantation by bolstering allogeneic responses resulting in leukemia elimination. In summary, 4-1BB ligation is a potent regulator of CD4+ and CD8+ T cell-mediated allogeneic responses in vivo. Modifying the ligation of 4-1BB represents a new approach to altering the graft-vs-host disease and graft-vs-leukemia effects of allogeneic T cells post bone marrow transplantation.
Immunobiology of Allograft Rejection in the Absence of IFN-γ: CD8+ Effector Cells Develop Independently of CD4+ Cells and CD40-CD40 Ligand Interactions
Authors: Bishop D. Keith , Wood Sherri Chan , Eichwald Ernst J. , Orosz Charles G. 
Published: April 2014

AbstractBoth wild-type (WT) and IFN-γ-deficient (IFN-γ−/−) C57BL/6 mice can rapidly reject BALB/c cardiac allografts. When depleted of CD8+ cells, both WT and IFN-γ−/− mice rejected their allografts, indicating that these mice share a common CD4-mediated, CD8-independent mechanism of rejection. However, when depleted of CD4+ cells, WT mice accepted their allografts, while IFN-γ−/− recipients rapidly rejected them. Hence, IFN-γ−/−, but not WT mice developed an unusual CD8-mediated, CD4-independent, mechanism of allograft rejection. Allograft rejection in IFN-γ−/− mice was associated with intragraft accumulation of IL-4-producing cells, polymorphonuclear leukocytes, and eosinophils. Furthermore, this form of rejection was resistant to treatment with anti-CD40 ligand (CD40L) mAb, which markedly prolonged graft survival in WT mice. T cell depletion studies verified that anti-CD40L treatment failed to prevent CD8-mediated allograft rejection in IFN-γ−/− mice. However, anti-CD40L treatment did prevent CD4-mediated rejection in IFN-γ−/− mice, although grafts were eventually rejected when CD8+ T cells repopulated the periphery. The IL-4 production and eosinophil influx into the graft that occurred during CD8-mediated rejection were apparently epiphenomenal, since treatment with anti-IL-4 mAb blocked intragraft accumulation of eosinophils, but did not interfere with allograft rejection. These studies demonstrate that a novel, CD8-mediated mechanism of allograft rejection, which is resistant to experimental immunosuppression, can develop when IFN-γ is limiting. An understanding of this mechanism is confounded by its association with Th2-like immune events, which contribute unique histopathologic features to the graft but are apparently unnecessary for the process of allograft rejection.
Functional Association of CD9 with the Fcγ Receptors in Macrophages
Authors: Kaji Keisuke , Takeshita Sunao , Miyake Kensuke , Takai Toshiyuki , Kudo Akira 
Published: April 2014

Abstract
CD9, a member of the tetraspan family of proteins, is highly expressed on macrophages. Although a clear function for the molecule has yet to be described, we have found that the anti-CD9 mAb activates mouse macrophages. The rat anti-CD9 mAb, KMC8.8, but not the F(ab′)2, induced tyrosine phosphorylation of proteins including syk and cbl and induced cell aggregation in the mouse macrophage cell line, J774, suggesting that co-cross-linking of CD9 and FcγR was required for the signal. Co-cross-linking of CD9-FcγR with KMC8.8 on macrophages from three different FcR-deficient mice, FcR γ-chain−/−, FcγRIIB−/−, and FcγRIII−/−, revealed that FcγRIII is specific and crucial for syk phosphorylation. Although both KMC8.8 and the anti-FcγRIIB/III mAb, 2.4G2, evoked similar phosphorylation patterns, only KMC8.8 induced cell aggregation. Additionally, KMC8.8 treatment led to reduce levels of TNF-α production and p42/44 extracellular signal-related kinase phosphorylation relative to 2.4G2 stimulation. Immunofluorescence staining showed that co-cross-linking of CD9-FcγR with KMC8.8 induced filopodium extension before cell aggregation, which was followed by simultaneous colocalization of CD9, FcγRIIB/III, Mac-1, ICAM-1, and F-actin at the cell-cell adhesion site. Moreover, KMC8.8 treatment of FcγR-deficient macrophages revealed that the colocalization of CD9, FcγRIII, Mac-1, and F-actin requires co-cross-linking of CD9-FcγRIII, whereas co-cross-linking of CD9-FcγRIIB induced the colocalization of only CD9 and FcγRIIB. Our results demonstrate that co-cross-linking of CD9 and FcγRs activates macrophages; therefore, CD9 may collaborate with FcRs functioning in infection and inflammation on macrophages.
Modes of Salmonid MHC Class I and II Evolution Differ from the Primate Paradigm
Authors: Shum Benny P. , Guethlein Lisbeth , Flodin Laura R. , Adkison Mark A. , Hedrick Ronald P. , Nehring R. Barry , Stet René J. M. , Secombes Christopher , Parham Peter 
Published: April 2014

AbstractRainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) represent two salmonid genera separated for 15–20 million years. cDNA sequences were determined for the classical MHC class I heavy chain gene UBA and the MHC class II β-chain gene DAB from 15 rainbow and 10 brown trout. Both genes are highly polymorphic in both species and diploid in expression. The MHC class I alleles comprise several highly divergent lineages that are represented in both species and predate genera separation. The class II alleles are less divergent, highly species specific, and probably arose after genera separation. The striking difference in salmonid MHC class I and class II evolution contrasts with the situation in primates, where lineages of class II alleles have been sustained over longer periods of time relative to class I lineages. The difference may arise because salmonid MHC class I and II genes are not linked, whereas in mammals they are closely linked. A prevalent mechanism for evolving new MHC class I alleles in salmonids is recombination in intron II that shuffles α1 and α2 domains into different combinations.
Novel Control Motif Cluster in the IgH δ-γ3 Interval Exhibits B Cell-Specific Enhancer Function in Early Development
Authors: Mundt Cornelia A. , Nicholson Ian C. , Zou Xiangang , Popov Andrei V. , Ayling Christine , Brüggemann Marianne 
Published: April 2014

AbstractThe majority of the human Ig heavy chain (IgH) constant (C) region locus has been cloned and mapped. An exception is the region between Cδ and Cγ3, which is unstable and may be a recombination hot spot. We isolated a pBAC clone (pHuIgH3′δ-γ3) that established a 52-kb distance between Cδ and Cγ3. Sequence analysis identified a high number of repeat elements, explaining the instability of the region, and an unusually large accumulation of transcription factor-binding motifs, for both lymphocyte-specific and ubiquitous transcription activators (IKAROS, E47, Oct-1, USF, Myc/Max), and for factors that may repress transcription (ΔEF1, Gfi-1, E4BP4, C/EBPβ). Functional analysis in reporter gene assays revealed the importance of the Cδ-Cγ3 interval in lymphocyte differentiation and identified independent regions capable of either enhancement or silencing of reporter gene expression and interaction with the IgH intron enhancer Eμ. In transgenic mice, carrying a construct that links the β-globin reporter to the novel δ-γ3 intron enhancer (Eδ-γ3), transgene transcription is exclusively found in bone marrow B cells from the early stage when IgH rearrangement is initiated up to the successful completion of H and L locus recombination, resulting in Ab expression. These findings suggest that the Cδ-Cγ3 interval exerts regulatory control on Ig gene activation and expression during early lymphoid development.
Gorillas with Spondyloarthropathies Express an MHC Class I Molecule with Only Limited Sequence Similarity to HLA-B27 that Binds Peptides with Arginine at P2
Authors: Urvater Julie A. , Hickman Heather , Dzuris John L. , Prilliman Kiley , Allen Todd M. , Schwartz Kevin J. , Lorentzen David , Shufflebotham Clare , Collins Edward J. , Neiffer Donald L. , Raphael Bonnie , Hildebrand William , Sette Alessandro , Watkins David I. 
Published: April 2014

AbstractThe human MHC class I gene, HLA-B27, is a strong risk factor for susceptibility to a group of disorders termed spondyloarthropathies (SpAs). HLA-B27-transgenic rodents develop SpAs, implicating HLA-B27 in the etiology of these disorders. Several nonhuman primates, including gorillas, develop signs of SpAs indistinguishable from clinical signs of humans with SpAs. To determine whether SpAs in gorillas have a similar HLA-B27-related etiology, we analyzed the MHC class I molecules expressed in four affected gorillas. Gogo-B01, isolated from three of the animals, has only limited similarity to HLA-B27 at the end of the α1 domain. It differs by several residues in the B pocket, including differences at positions 45 and 67. However, the molecular model of Gogo-B*0101 is consistent with a requirement for positively charged residues at the second amino acid of peptides bound by the MHC class I molecule. Indeed, the peptide binding motif and sequence of individual ligands eluted from Gogo-B*0101 demonstrate that, like HLA-B27, this gorilla MHC class I molecule binds peptides with arginine at the second amino acid position of peptides bound by the MHC class I molecule. Furthermore, live cell binding assays show that Gogo-B*0101 can bind HLA-B27 ligands. Therefore, although most gorillas that develop SpAs express an MHC class I molecule with striking differences to HLA-B27, this molecule binds peptides similar to those bound by HLA-B27.
Structural and Functional Consequences of Altering a Peptide MHC Anchor Residue
Authors: Kersh Gilbert J. , Miley Michael J. , Nelson Christopher A. , Grakoui Arash , Horvath Stephen , Donermeyer David L. , Kappler John , Allen Paul M. , Fremont Daved H. 
Published: April 2014

AbstractTo better understand TCR discrimination of multiple ligands, we have analyzed the crystal structures of two Hb peptide/I-Ek complexes that differ by only a single amino acid substitution at the P6 anchor position within the peptide (E73D). Detailed comparison of multiple independently determined structures at 1.9 Å resolution reveals that removal of a single buried methylene group can alter a critical portion of the TCR recognition surface. Significant variance was observed in the peptide P5-P8 main chain as well as a rotamer difference at LeuP8, ∼10 Å distal from the substitution. No significant variations were observed in the conformation of the two MHC class II molecules. The ligand alteration results in two peptide/MHC complexes that generate bulk T cell responses that are distinct and essentially nonoverlapping. For the Hb-specific T cell 3.L2, substitution reduces the potency of the ligand 1000-fold. Soluble 3.L2 TCR binds the two peptide/MHC complexes with similar affinity, although with faster kinetics. These results highlight the role of subtle variations in MHC Ag presentation on T cell activation and signaling.
Soluble CD16 Inhibits CR3 (CD11b/CD18)-Mediated Infection of Monocytes/Macrophages by Opsonized Primary R5 HIV-1
Authors: Bouhlal Hicham , Galon Jérôme , Kazatchkine Michel D. , Fridman Wolf-Herman , Sautès-Fridman Catherine , Haeffner Cavaillon Nicole 
Published: April 2014

AbstractWe demonstrate that soluble CD16 (sCD16; soluble FcγRIII), a natural ligand of CR3, inhibits the infection of monocytes by primary R5 HIV-1 strain opsonized with serum of seronegative individuals. Inhibition of monocyte infection by sCD16 was similar to that observed with anti-CR3 mAbs, indicating that opsonized HIV may use a CR3-dependent pathway for entry in monocytic cells. Cultured human monocytes express both CR3 (CD11b/CD18) and CCR5 receptors. RANTES, the natural ligand of CCR5, inhibited infection of monocytes with unopsonized HIV particles and partially that of monocytes infected with HIV particles opsonized with complement-derived fragments. Although HIV-infected monocytes from homozygous CCR5 Δ 32/Δ 32 (CCR5−/−) individuals produce low levels of p24, cells infected with opsonized particles produced higher levels of p24 than cells infected with unopsonized particles. Our results thus suggest that CR3 may represent an alternative coreceptor to CCR5 of opsonized primary R5 virus entry into monocytes/macrophages. We also observed that the concentration of sCD16 is greatly decreased in sera of HIV-infected patients with low lymphocyte CD4+ counts. Taken together, our findings suggest that sCD16, present in plasma, may play an important role in controlling HIV-1 spread.
Contribution of Th1 and Th2 Cells to Protection and Pathology in Experimental Models of Granulomatous Lung Disease
Authors: Wangoo Arun , Sparer Tim , Brown Ivor N. , Snewin Valerie A. , Janssen Riny , Thole Jelle , Cook H. Terence , Shaw Rory J. , Young Douglas B. 
Published: April 2014

AbstractMice that had received adoptive transfer of DO11.10 TCR transgenic T cells polarized toward a Th1 or a Th2 phenotype were challenged with Ag-coated beads or with recombinant Mycobacterium tuberculosis expressing the OVA determinant. The resulting bead-induced pulmonary granulomas reflected the phenotype of the adoptively transferred T cells, with the Th2 cells promoting a fibrotic reaction. Mice receiving Th1 cells mounted an epitope-specific protective response to challenge with recombinant M. tuberculosis. Th2 recipients were characterized by enhanced weight loss and lung fibrosis during acute high-dose infection. The combination of TCR transgenic T cells and epitope-tagged mycobacteria provides a novel experimental model for investigation of the pathogenesis of tuberculosis.
Prophylactic Tumor Vaccination: Comparison of Effector Mechanisms Initiated by Protein Versus DNA Vaccination
Authors: Zöller Margot , Christ Oliver 
Published: April 2014

AbstractClinical success in tumor vaccination frequently does not reach expectation. Since vaccination protocols are quite variable, we used the murine renal cell carcinoma line RENCA transfected with the lacZ gene (RENCA-β-gal) to compare the efficacy of two different vaccination strategies or their combination and to elaborate on the underlying mechanisms. BALB/c mice were vaccinated either with naked lacZ DNA or with attenuated Salmonella typhimurium transformed with lacZ DNA or with dendritic cells (DC) loaded with the β-galactosidase protein or mice were vaccinated with both DNA and protein. Although all regimens led to a prolongation of survival time, oral vaccination with transfected S. typhimurium followed by i.v. transfer of protein-loaded DC provided the optimal schedule. In this setting, &gt;50% of mice remained tumor free after challenge with 10 times the lethal tumor dose of RENCA-β-gal. As explored in transfer experiments, the superior efficacy of combining DNA and protein vaccination is due to the facts that 1) optimal protection depends on both activated CD4+ and CD8+ cells and 2) CD8+ CTL are most strongly activated by vaccination with transformed Salmonella, whereas vaccination with protein-loaded DC is superior for the activation of Th. The latter induced sustained activation of CTL and recruitment of nonadaptive defense mechanisms. The data demonstrate the strength of DNA vaccination, particularly by the oral route, and provide evidence that a combined treatment with protein-loaded DC can significantly increase the therapeutic efficacy.
Maturation Versus Death of Developing Double-Positive Thymocytes Reflects Competing Effects on Bcl-2 Expression and Can Be Regulated by the Intensity of CD28 Costimulation
Authors: McKean David J. , Huntoon Catherine J. , Bell Michael P. , Tai Xuguang , Sharrow Susan , Hedin Karen E. , Conley Abigail , Singer Alfred 
Published: April 2014

AbstractImmature double-positive (DP) thymocytes mature into CD4+CD8− cells in response to coengagement of TCR with any of a variety of cell surface “coinducer” receptors, including CD2. In contrast, DP thymocytes are signaled to undergo apoptosis by coengagement of TCR with CD28 costimulatory receptors, but the molecular basis for DP thymocyte apoptosis by TCR plus CD28 coengagement is not known. In the present study, we report that TCR plus CD28 coengagement does not invariably induce DP thymocyte apoptosis but, depending on the intensity of CD28 costimulation, can induce DP thymocyte maturation. We demonstrate that distinct but interacting signal transduction pathways mediate DP thymocyte maturation signals and DP thymocyte apoptotic signals. Specifically, DP maturation signals are transduced by the extracellular signal-related kinase (ERK)/mitogen-activated protein kinase (MAPK) pathway and up-regulate expression of the antiapoptotic protein Bcl-2. In contrast, the apoptotic response stimulated by CD28 costimulatory signals is mediated by ERK/MAPK-independent pathways. Importantly, when TCR-activated thymocytes are simultaneously coengaged by both CD28 and CD2 receptors, CD28 signals can inhibit ERK/MAPK-dependent Bcl-2 protein up-regulation. Thus, there is cross-talk between the signal transduction pathways that transduce apoptotic and maturation responses, enabling CD28-initiated signal transduction pathways to both stimulate DP thymocyte apoptosis and also negatively regulate maturation responses initiated by TCR plus CD2 coengagement.