bluuebunny/crossref_metadata_2025_split huggingface dataset:
B Cell Developmental Requirement for the Gαi2 Gene
Authors: Dalwadi Harnisha , Wei Bo , Schrage Matthew , Su Tom T. , Rawlings David J. , Braun Jonathan 
Published: April 2014

Abstract
Null mutation of the Gαi2 trimeric G protein results in a discrete and profound mucosal disorder, including inflammatory bowel disease (IBD), attenuation of IL-10 expression, and immune function polarized to Th1 activity. Genetic and adoptive transfer experiments have established a role for B cells and IL-10 in mucosal immunologic homeostasis and IBD resistance. In this study, we addressed the hypothesis that Gαi2 is required for the development of IL-10-producing B cells. Gαi2−/− mice were reduced in the relative abundance of marginal zone (MZ), transitional type 2 (T2), and B-1a B cells and significantly increased in follicular mature and B-1b B cells. Reconstitution of RAG2−/− mice with Gαi2−/− bone marrow induced an IBD-like colitis and a deficiency in absolute numbers of MZ, T2, and B-1 B cells. Thus, the Gαi2−/− genotype in colitis susceptibility and B cell development involved a cis effect within the hemopoietic compartment. In vitro, the B cell population of Gαi2−/− mice was functionally deficient in LPS-induced proliferation and IL-10 production, consistent with the exclusive capacity of T2 and MZ cell subpopulations for LPS responsiveness. In vivo, Gαi2−/− mice were selectively impaired for the IgM response to T-independent type II, consistent with the relative depletion of MZ and peritoneal B-1 subpopulations. Collectively, these results reveal a selective role for Gαi2 in MZ and B-1 B cell development. Disorders of this Gαi2-dependent process in B cell development may represent a mechanism for IBD susceptibility.
Preferential Survival of CD8 T and NK Cells Expressing High Levels of CD94
Authors: Gunturi Anasuya , Berg Rance E. , Forman James 
Published: April 2014

Abstract
The Qa-1b/Qdm tetramer binds to CD94/NKG2 receptors expressed at high levels on ∼50% of murine NK cells. Although very few CD8 T cells from naive mice express CD94/NKG2 receptors, ∼50% of CD8 T cells taken from mice undergoing a secondary response against Listeria monocytogenes (LM) are CD94high and bind the tetramer. Although CD94int NK cells do not bind the tetramer, CD94int CD8 T cells do, and this binding is dependent on the CD8 coreceptor. We found that the extent of apoptosis in CD8 T and NK cells was inversely related to the expression of CD94, with lower levels of apoptosis seen in CD94high cells after 1–3 days of culture. The difference in CD8 T cell survival was evident as early as 6 h after culture and persisted until nearly all the CD94neg/int cells were apoptotic by 48 h. In contrast, expression of inhibitory Ly-49A,G2,C/I molecules was associated with higher levels of apoptosis. Cross-linking CD94/NKG2 receptors on CD8 T cells from a mouse undergoing an LM infection further reduced the percentage of apoptotic cells on the CD94-expressing populations, while cross-linking Ly-49I had no effect on CD8 T cells expressing Ly-49I. Cross-linking CD3 on CD8 T cells from a mouse undergoing a secondary LM infection increases the extent of apoptosis, but this is prevented by cross-linking CD94/NKG2 receptors at the same time. Similar results were observed with NK cells in that the CD94high population displayed less apoptosis than CD94int cells after 1–3 days in culture. Therefore, the expression of CD94/NKG2 is correlated with a lower level of apoptosis and may play an important role in the maintenance of CD8 T and NK cells.
Expression of IFN-γ Upon Triggering of Activating Ly49D NK Receptors In Vitro and In Vivo: Costimulation with IL-12 or IL-18 Overrides Inhibitory Receptors
Authors: Ortaldo John R. , Young Howard A. 
Published: April 2014

AbstractNK cells can express both activating and inhibitory Ly49 receptors on their cell surface. When cells expressing both receptors are presented with a ligand, inhibition dominates the functional outcome. In this report we demonstrate that costimulation of the activating Ly49D murine NK cell receptor with IL-12 or IL-18 is capable of over-riding the inhibitory Ly49G2 receptor blockade for cytokine production both in vitro and in vivo. This synergy is mediated by and dependent upon Ly49D-expressing NK cells and results in significant systemic expression of IFN-γ. This would place NK cells and their activating Ly-49 receptors as important initiators of microbial, antiviral, and antitumor immunity and provide a mechanism for the release of activating Ly49 receptors from inhibitory receptor blockade.
Antigen Density Presented By Dendritic Cells In Vivo Differentially Affects the Number and Avidity of Primary, Memory, and Recall CD8+ T Cells
Authors: Bullock Timothy N. J. , Mullins David W. , Engelhard Victor H. 
Published: April 2014

AbstractWe studied the size and avidity of primary and recall CD8+ T cell responses in vivo in mice immunized with dendritic cells presenting different densities of a MHC class I-restricted peptide. Increasing the epitope density on a fixed number of dendritic cells increased the size of the primary response, yet had no influence on the avidity of the effector cells. However, epitope density-based selection of cells with different avidities was evident in the subsequent memory population, and in recall responses. Additionally, mice primed with different peptide densities had similarly sized quiescent memory and recall responses. Our findings provide evidence for an important role for epitope density in the selection of T cells in vivo.
Temperature Effect on IgE Binding to CD23 Versus FcεRI
Authors: Chen Bing-Hung , Kilmon Michelle A. , Ma Check , Caven Timothy H. , Chan-Li Yee , Shelburne Anne E. , Tombes Robert M. , Roush Eric , Conrad Daniel H. 
Published: April 2014

Abstract
A chimeric soluble CD23, consisting of the extracellular domain of mouse CD23 and a modified leucine zipper (lz-CD23), has been shown to inhibit IgE binding to the FcεRI. A similar human CD23 construct was also shown to inhibit binding of human IgE to human FcεRI. In both systems, the inhibition was found to be temperature dependent; a 10-fold molar excess of lz-CD23 gave 90–98% inhibition at 4°C, dropping to 20–30% inhibition at 37°C. Surface plasmon resonance analysis of lz-CD23 binding to an IgE-coated sensor chip suggested that the effective concentration of lz-CD23 was lower at the higher temperatures. Analysis of 125I-IgE binding to CD23+-Chinese hamster ovary cells also indicated that increased temperature resulted in a lower percentage of IgE capable of interacting with CD23. In contrast, IgE interacts more effectively with FcεRI+-rat basophilic leukemia cells at 37°C compared with 4°C. The results support the concept that the open and closed IgE structures found by crystallography interact differently with the two IgE receptors and suggest that temperature influences the relative percentage of IgE in the respective structural forms. Changes in CD23 oligomerization also plays a role in the decreased binding seen at physiological temperatures.
Immunoglobulin Superantigen Protein L Induces IL-4 and IL-13 Secretion from Human FcεRI+ Cells Through Interaction with the κ Light Chains of IgE
Authors: Genovese Arturo , Borgia Guglielmo , Björck Lars , Petraroli Angelica , de Paulis Amato , Piazza Marcello , Marone Gianni 
Published: April 2014

Abstract
Peptostreptococcus magnus protein L is a multidomain bacterial surface protein that correlates with virulence. It consists of up to five homologous Ig-binding domains (B1–B5) that interact with the variable domain of Ig κ L chains. Intact protein L stimulates the synthesis and the release of IL-4 and IL-13 from human basophils in vitro. A protein L fragment covering the Ig-binding domains B1–B4 also induced IL-4 and IL-13 release from basophils. There was an excellent correlation (rs = 0.82; p &lt; 0.001) between the maximal percent IL-4 release induced by protein L and that induced by anti-IgE and between intact protein L and the B1–B4 fragment (rs = 0.90; p &lt; 0.01). Removal of IgE bound to basophils markedly reduced the IL-4 release induced by anti-IgE, protein L, and B1–B4. Preincubation of basophils with protein L or anti-IgE caused complete cross-desensitization to subsequent challenge with the heterologous stimulus. IgE purified from myeloma patients PS and PP (λ chains) blocked anti-IgE-induced IL-4 release, but not the releasing activity of protein L. In contrast, IgE purified from myeloma patient ADZ (κ chains) blocked both anti-IgE- and protein L-induced secretion. Cyclosporin A, but not cyclosporin H, inhibited protein L-induced release of IL-4 and IL-13 from basophils. Thus, protein L acts as a bacterial Ig superantigen to induce the synthesis and release of IL-4 and IL-13 from basophils by interacting with κ L chains of the IgE isotype.
Characterization of Thymic Progenitors in Adult Mouse Bone Marrow
Authors: Perry S. Scott , Pierce L. Jeanne , Slayton William B. , Spangrude Gerald J. 
Published: April 2014

Abstract
Thymic cellularity is maintained throughout life by progenitor cells originating in the bone marrow. In this study, we describe adult mouse bone cells that exhibit several features characteristic of prothymocytes. These include 1) rapid thymic engraftment kinetics following i.v. transplantation, 2) dramatic expansion of thymic progeny, and 3) limited production of hemopoietic progeny other than thymocytes. The adult mouse bone marrow population that is depleted of cells expressing any of a panel of lineage-specific Ags, stem cell Ag-1 positive, and not expressing the Thy1.1 Ag (Thy1.1−) (Thy1.1− progenitors) can repopulate the thymus 9 days more rapidly than can hemopoietic stem cells, a rate of thymic repopulation approaching that observed with transplanted thymocytes. Additionally, Thy1.1− progenitors expand prolifically to generate thymocyte progeny comparable in absolute numbers to those observed from parallel hemopoietic stem cell transplants, and provide a source of progenitors that spans multiple waves of thymic seeding. Nevertheless, the Thy1.1− population yields relatively few B cells and rare myeloid progeny posttransplant. These observations describe the phenotype of an adult mouse bone marrow population highly enriched for rapidly engrafting, long-term thymocyte progenitors. Furthermore, they note disparity in B and T cell expansion from this lymphoid progenitor population and suggest that it contains the progenitor primarily responsible for seeding the thymus throughout life.
Restoration of Ig Secretion: Mutation of Germline-Encoded Residues in T15L Chains Leads to Secretion of Free Light Chains and Assembled Antibody Complexes Bearing Secretion-Impaired Heavy Chains
Authors: Whitcomb Elizabeth A. , Martin Tammy M. , Rittenberg Marvin B. 
Published: April 2014

Abstract
We previously described T15H chain mutants that were impaired in assembly with L chain and in ability to be secreted from the cell. The unmutated T15L chain is unusual in that it is secretion-impaired in the absence of assembly with H chain. The T15L chain preferentially pairs with T15H in vivo, suggesting that if we introduced mutations that would allow secretion of free T15L chain, they might also lead to the secretion of the complex with the defective H chain. We mutated four positions in the germline T15L that had amino acids infrequently found in other κ-chains. Mutation to the most frequently occurring amino acid at three of the four positions allowed secretion of free L chain, while the combination of two secretion-restoring mutations was synergistic. Coexpression of secretion-restored mutant L chains with the secretion-defective mutant H chains rescued secretion of the assembled H2L2 complex, suggesting that during somatic hypermutation in vivo, deleterious mutations at the H chain may be compensated by mutations on the L chain. To our knowledge, this is the first example of mutations in IgL chains that are able to restore secretion-defective H chains to secretion competence in mammalian cells.
Crystal Structure of a Hydrophobic Immunodominant Antigenic Site on Hepatitis C Virus Core Protein Complexed to Monoclonal Antibody 19D9D6
Authors: Ménez Renée , Bossus Marc , Muller Bruno H. , Sibaï Geneviève , Dalbon Pascal , Ducancel Frédéric , Jolivet-Reynaud Colette , Stura Enrico A. 
Published: April 2014

Abstract
The first crystal structure of a complex between a hepatitis C virus (HCV) core protein-derived peptide (residues 13–40) and the Ab fragment of a murine mAb (19D9D6) has been solved, allowing determination of the recognized epitope and elucidation of its conformation. This Ab, raised against the first 120 residues of the core protein, recognizes core particles and strongly competes with anticore human Abs, suggesting that it is highly representative of the human anti-HCV core response. Its epitope lies within the first 45 aa of the protein, the major antigenic segment of core recognized both by murine and human Abs. Surprisingly, the recognized epitope (29–37: QIVGGVYLL) has an unusual preponderance of hydrophobic residues, some of which are buried in a small hydrophobic core in the nuclear magnetic resonance structure of the peptide (2–45) in solution, suggesting that the Ab may induce a structural rearrangement upon recognition. The flexibility may reside entirely within the Ag, since the Fab′-peptide complex structure at 2.34 Å shows that the Ab binding site is hardly perturbed by complexation. Given that the recognized residues are unlikely to be solvent exposed, we are left with the interesting possibility that Ab-core interactions may take place in a nonaqueous environment.
Associations of MHC Ancestral Haplotypes with Resistance/Susceptibility to AIDS Disease Development
Authors: Flores-Villanueva Pedro O. , Hendel Houria , Caillat-Zucman Sophie , Rappaport Jay , Burgos-Tiburcio Alberto , Bertin-Maghit Sebastien , Ruiz-Morales Jorge A. , Teran Maria E. , Rodriguez-Tafur Juan , Zagury Jean-François 
Published: April 2014

Abstract
We tested the association of MHC ancestral haplotypes with rapid or slow progression to AIDS by comparing their frequencies in the French genetics of resistance/susceptibility to immunodeficiency virus cohort with that reported in a control French population. Seven ancestral haplotypes were identified in the genetics of resistance/susceptibility to immunodeficiency virus cohort with a frequency &gt;1%. The 8.1 (odds ratio (OR) = 3, p = 0.006), 35.1 (OR = 5.7, p = 0.001), and 44.2 (OR = 3.4, p = 0.007) ancestral haplotypes were associated with rapid progression, whereas the 35.2 (OR = 3.6, p = 0.001), 44.1 (OR = 5.4, p &lt; 10−4), and 57.1 (OR = 5.8, p &lt; 10−4) ancestral haplotypes were associated with slow progression to AIDS. Although the frequency of each ancestral haplotype is low in the population, the OR were quite higher than those previously obtained for single HLA allele associations, with some p values as low as 10−4. The analysis of the recombinant fragments of these haplotypes allowed the identification of the MHC regions in the 35.1, 35.2, and 44.2 haplotypes associated with rapid progression to AIDS and the MHC regions of the 44.1 and 57.1 haplotypes associated with slow progression to AIDS. Previous studies have identified single HLA alleles associated with disease progression. Our results on recombinant fragments confirm the direct role of HLA-B35 in rapid progression. Associations with HLA-A29 and -B57 might be due to linkage disequilibrium with other causative genes within the MHC region.
Constrained Intracellular Survival ofMycobacterium tuberculosisin Human Dendritic Cells
Authors: Tailleux Ludovic , Neyrolles Olivier , Honoré-Bouakline Stéphanie , Perret Emmanuelle , Sanchez Françoise , Abastado Jean-Pierre , Lagrange Philippe Henri , Gluckman Jean Claude , Rosenzwajg Michelle , Herrmann Jean-Louis 
Published: April 2014

AbstractDendritic cells (DCs) are likely to play a key role in immunity against Mycobacterium tuberculosis, but the fate of the bacterium in these cells is still unknown. Here we report that, unlike macrophages (Mφs), human monocyte-derived DCs are not permissive for the growth of virulent M. tuberculosis H37Rv. Mycobacterial vacuoles are neither acidic nor fused with host cell lysosomes in DCs, in a mode similar to that seen in mycobacterial infection of Mφs. However, uptake of the fluid phase marker dextran, and of transferrin, as well as accumulation of the recycling endosome-specific small GTPase Rab11 onto the mycobacterial phagosome, are almost abolished in infected DCs, but not in Mφs. Moreover, communication between mycobacterial phagosomes and the host-cell biosynthetic pathway is impaired, given that &lt;10% of M. tuberculosis vacuoles in DCs stained for the endoplasmic reticulum-specific proteins Grp78/BiP and calnexin. This correlates with the absence of the fusion factor N-ethylmaleimide-sensitive factor onto the vacuolar membrane in this cell type. Trafficking between the vacuoles and the host cell recycling and biosynthetic pathways is strikingly reduced in DCs, which is likely to impair access of intracellular mycobacteria to essential nutrients and may thus explain the absence of mycobacterial growth in this cell type. This unique location of M. tuberculosis in DCs is compatible with their T lymphocyte-stimulating functions, because M. tuberculosis-infected DCs have the ability to specifically induce cytokine production by autologous T lymphocytes from presensitized individuals. DCs have evolved unique subcellular trafficking mechanisms to achieve their Ag-presenting functions when infected by intracellular mycobacteria.
The Induction and Kinetics of Antigen-Specific CD8 T Cells Are Defined by the Stage Specificity and Compartmentalization of the Antigen in Murine Toxoplasmosis
Authors: Kwok Lai-Yu , Lütjen Sonja , Soltek Sabine , Soldati Dominique , Busch Dirk , Deckert Martina , Schlüter Dirk 
Published: April 2014

Abstract
Toxoplasma gondii forms different life stages, fast-replicating tachyzoites and slow-growing bradyzoites, in mammalian hosts. CD8 T cells are of crucial importance in toxoplasmosis, but it is unknown which parasite stage is recognized by CD8 T cells. To analyze stage-specific CD8 T cell responses, we generated various recombinant Toxoplasma gondii expressing the heterologous Ag β-galactosidase (β-gal) and studied whether 1) secreted or cytoplasmic Ags and 2) tachyzoites or bradyzoites, which persist intracerebrally, induce CD8 T cells. We monitored the frequencies and kinetics of β-gal-specific CD8 T cells in infected mice by MHC class I tetramer staining. Upon oral infection of B6C (H-2bxd) mice, only β-gal-secreting tachyzoites induced β-gal-specific CD8 T cells. However, upon secondary infection of mice that had received a primary infection with tachyzoites secreting β-gal, β-gal-secreting tachyzoites and bradyzoites transiently increased the frequency of intracerebral β-gal-specific CD8 T cells. Frequencies of splenic and cerebral β-gal-specific CD8 T cells peaked at day 23 after infection, thereafter persisting at high levels in the brain but declining in the spleen. Splenic and cerebral β-gal-specific CD8 T cells produced IFN-γ and were cytolytic upon specific restimulation. Thus, compartmentalization and stage specificity of an Ag determine the induction of CD8 T cells in toxoplasmosis.
CD4+ T Cells Mediate Abscess Formation in Intra-abdominal Sepsis by an IL-17-Dependent Mechanism
Authors: Chung Doo Ryeon , Kasper Dennis L. , Panzo Ronald J. , Chtinis Tanuja , Grusby Michael J. , Sayegh Mohamed H. , Tzianabos Arthur O. 
Published: April 2014

Abstract
Abscess formation associated with intra-abdominal sepsis causes severe morbidity and can be fatal. Previous studies have implicated T cells in the pathogenesis of abscess formation, and we have recently shown that CD4+ T cells activated in vitro by zwitterionic capsular polysaccharides from abscess-inducing bacteria such as Staphylococcus aureus and Bacteroides fragilis initiate this host response when transferred to naive rats. In this study, we show that mice deficient in αβTCR-bearing T cells or CD4+ T cells fail to develop abscesses following challenge with B. fragilis or abscess-inducing zwitterionic polysaccharides, compared with CD8−/− or wild-type animals. Transfer of CD4+ T cells from wild-type mice to αβTCR−/− animals reconstituted this ability. The induction of abscesses required T cell costimulation via the CD28-B7 pathway, and T cell transfer experiments with STAT4−/− and STAT6−/− mice demonstrated that this host response is dependent on STAT4 signaling. Significantly higher levels of IL-17, a proinflammatory cytokine produced almost exclusively by activated CD4+ T cells, were associated with abscess formation in Th2-impaired (STAT6−/−) mice, while STAT4−/− mice had significantly lower levels of this cytokine than control animals. The formation of abscesses was preceded by an increase in the number of activated CD4+ T cells in the peritoneal cavity 24 h following bacterial challenge. Confocal laser-scanning microscopy analysis revealed that CD4+ T cells comprise the abscess wall in these animals and produce IL-17 at this site. Administration of a neutralizing Ab specific for IL-17 prevented abscess formation following bacterial challenge in mice. These data delineate the specific T cell response necessary for the development of intra-abdominal abscesses and underscore the role of IL-17 in this disease process.
Prevention of Spontaneous Breast Carcinoma by Prophylactic Vaccination with Dendritic/Tumor Fusion Cells
Authors: Xia Jianchuan , Tanaka Yasuhiro , Koido Shigeo , Liu Chunlei , Mukherjee Pinku , Gendler Sandra J. , Gong Jianlin 
Published: April 2014

Abstract
Genetically modified mice with spontaneous development of mammary carcinoma provide a powerful tool to study the efficacy of tumor vaccines, since they mimic breast cancer development in humans. We used a transgenic murine model expressing polyomavirus middle T oncogene and mucin 1 tumor-associated Ag to determine the preventive effect of a dendritic/tumor fusion cell vaccine. The MMT (a transgenic murine model) mice developed mammary carcinoma between the ages of 65–108 days with 100% penetrance. No spontaneous CTL were detected. However, prophylactic vaccination of MMT mice with dendritic/tumor fusion cells induced polyclonal CTL activity against spontaneous mammary carcinoma cells and rendered 57–61% of the mice free of the disease at the end of experiment (180 days). Furthermore, the level of CTL activity was maintained with multiple vaccinations. The antitumor immunity induced by vaccination with dendritic/tumor fusion cells reacted differently to injected tumor cells and autochthonous tumor. Whereas the injected tumor cells were rejected, the autochthonous tumor evaded the attack and was allowed to grow. Collectively these results indicate that prophylactic vaccination with dendritic/tumor fusion cells confers sufficient antitumor immunity to counter the tumorigenesis of potent oncogenic products. The findings in the present study are highly relevant to cancers in humans.