bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystallographic Structure of a Rheumatoid Arthritis MHC Susceptibility Allele, HLA-DR1 (DRB1*0101), Complexed with the Immunodominant Determinant of Human Type II Collagen
Authors: Rosloniec Edward F. , Ivey Robert A. , Whittington Karen B. , Kang Andrew H. , Park Hee-Won 
Published: April 2014

Abstract
The expression of HLA-DR1 (DRB1*0101) is associated with an enhanced risk for developing rheumatoid arthritis (RA). To study its function, we have solved the three-dimensional structure of HLA-DR1 complexed with a candidate RA autoantigen, the human type II collagen peptide CII (259–273). Based on these structural data, the CII peptide is anchored by Phe263 at the P1 position and Glu266 at P4. Surprisingly, the Lys at the P2 position appears to play a dual role by participating in peptide binding via interactions with DRB1-His81 and Asn82, and TCR interaction, based on functional assays. The CII peptide is also anchored by the P4 Glu266 residue through an ionic interaction with DRB1-Arg71 and Glu28. Participation of DRB1-Arg71 is significant because it is part of the shared epitope expressed by DR alleles associated with RA susceptibility. Potential anchor residues at P6 and P9 of the CII peptide are both Gly, and the lack of side chains at these positions appears to result in both a narrower binding groove with the peptide protruding out of the groove at this end of the DR1 molecule. From the TCR perspective, the P2-Lys264, P5-Arg267, and P8-Lys270 residues are all oriented away from the binding groove and collectively represent a positive charged interface for CII-specific TCR binding. Comparison of the DR1-CII structure to a DR1-hemagglutinin peptide structure revealed that the binding of these two peptides generates significantly different interfaces for the interaction with their respective Ag-specific TCRs.
Fluorescence-Activated Cell Sorting and Cloning of Bona Fide CD8+ CTL with Reversible MHC-Peptide and Antibody Fab′ Conjugates
Authors: Guillaume Philippe , Baumgaertner Petra , Angelov Georgi S. , Speiser Daniel , Luescher Immanuel F. 
Published: April 2014

Abstract
The isolation of subsets of Ag-specific T cells for in vitro and in vivo studies by FACS is compromised by the fact that the soluble MHC-peptide complexes and Abs used for staining, especially when combined, induce unwanted T cell activation and eventually apoptosis. This is especially a problem for CD8+ CTL, which are susceptible to activation-dependent cell death. In this study, we show that reversible MHC-peptide complexes (tetramers) can be prepared by conjugating MHC-peptide monomers with desthiobiotin (DTB; also called dethiobiotin) and multimerization by reaction with fluorescent streptavidin. While in the cold these reagents are stable and allow good staining, they rapidly dissociate in monomers at elevated temperatures, especially in the presence of free biotin. FACS cloning of Melan-A (MART-1)-specific CTL from a melanoma-infiltrated lymph node with reversible HLA-A2 Melan-A26–35 multimers yielded over two times more clones than when using the conventional biotin-containing multimers. CTL clones obtained by means of reversible multimers killed Melan-A-positive tumor cells more efficiently as compared with clones obtained with the stable multimers. Among the CTL obtained with the reversible multimers, but much less among those obtained with the stable multimers, a high proportion of clones exhibited high functional and physical avidity and died upon incubation with soluble MHC-peptide complexes. Finally, we show that Fab′ of an anti-CD8 Ab can be converted in reversible DTB streptavidin conjugates the same way. These DTB reagents efficiently and reversibly stained murine and human CTL without affecting their viability.
Sites in the CH3 Domain of Human IgA1 That Influence Sensitivity to Bacterial IgA1 Proteases
Authors: Senior Bernard W. , Woof Jenny M. 
Published: April 2014

Abstract
The influence of regions, other than the hinge, on the susceptibility of human IgA1 to cleavage by diverse bacterial IgA1 proteases, was examined using IgA1 mutants bearing amino acid deletions, substitutions, and domain swaps. IgA1 lacking the tailpiece retained its susceptibility to cleavage by all of the IgA1 proteases. The domain swap molecule α1α2γ3, in which the CH3 domain of IgA1 was exchanged for that of human IgG1, was resistant to cleavage with the type 1 and 2 serine IgA1 proteases of Neisseria meningitidis, Neisseria gonorrhoeae, and Haemophilus influenzae, but remained sensitive to cleavage with the metallo-IgA1 proteases of Streptococcus pneumoniae, Streptococcus oralis, Streptococcus sanguis, and Streptococcus mitis. Substitution of the IgA1 Cα3 domain motif Pro440-Phe443 into the corresponding position in the Cγ3 domain of α1α2γ3 resulted now in sensitivity to the type 2 IgA1 protease of N. meningitidis, indicating the possible requirement of these amino acids for sensitivity to this protease. For the H. influenzae type 2 protease, resistance of an IgA1 mutant in which the CH3 domain residues 399–409 were exchanged with those from IgG1, but sensitivity of mutant HuBovα3 in which the Cα3 domain of bovine IgA replaces that of human IgA1, suggests that CH3 domain residues Glu403, Gln406, and Thr409 influence sensitivity to this enzyme. Hence, unlike the situation with the metallo-IgA1 proteases of Streptococcus spp., the sensitivity of human IgA1 to cleavage with the serine IgA1 proteases of Neisseria and Haemophilus involves their binding to different sites specifically in the CH3 domain.
Backcross and Partial Advanced Intercross Analysis of Nonobese Diabetic Gene-Mediated Effects on Collagen-Induced Arthritis Reveals an Interactive Effect by Two Major Loci
Authors: Lindqvist Anna-Karin B. , Johannesson Martina , Johansson Åsa C. M. , Nandakumar Kutty S. , Blom Anna M. , Holmdahl Rikard 
Published: April 2014

Abstract
Genetic segregation analysis between NOD and C57BL strains have been used to identify loci associated with autoimmune disease. Only two loci (Cia2 and Cia9) had earlier been found to control development of arthritis, whereas none of the previously identified diabetes loci was of significance for arthritis. We have now made a high-powered analysis of a backcross of NOD genes on to the B10.Q strain for association with collagen-induced arthritis. We could confirm relevance of both Cia2 and Cia9 as well as the interaction between them, but we did not identify any other significant arthritis loci. Immune cellular subtyping revealed that Cia2 was also associated with the number of blood macrophages. Congenic strains of the Cia2 and Cia9 loci on the B10.Q background were made and used to establish a partial advanced intercross (PAI). Testing the PAI mice for development of collagen-induced arthritis confirmed the loci and the interactions and also indicated that at least two genes contribute to the Cia9 locus. Furthermore, it clearly showed that Cia2 is dominant protective but that the protection is not complete. Because these results may indicate that the Cia2 effect on arthritis is not only due to the deficiency of the complement C5, we analyzed complement functions in the Cia2 congenics as well as the PAI mice. These data show that not only arthritis but also C5-dependent complement activity is dominantly suppressed, confirming that C5 is one of the major genes explaining the Cia2 effect.
Human Cytomegalovirus Alters Localization of MHC Class II and Dendrite Morphology in Mature Langerhans Cells
Authors: Lee Andrew W. , Hertel Laura , Louie Ryan K. , Burster Timo , Lacaille Vashti , Pashine Achal , Abate Davide A. , Mocarski Edward S. , Mellins Elizabeth D. 
Published: April 2014

Abstract
Hemopoietic stem cell-derived mature Langerhans-type dendritic cells (LC) are susceptible to productive infection by human CMV (HCMV). To investigate the impact of infection on this cell type, we examined HLA-DR biosynthesis and trafficking in mature LC cultures exposed to HCMV. We found decreased surface HLA-DR levels in viral Ag-positive as well as in Ag-negative mature LC. Inhibition of HLA-DR was independent of expression of unique short US2-US11 region gene products by HCMV. Indeed, exposure to UV-inactivated virus, but not to conditioned medium from infected cells, was sufficient to reduce HLA-DR on mature LC, implicating particle binding/penetration in this effect. Reduced surface levels reflected an altered distribution of HLA-DR because total cellular HLA-DR was not diminished. Accumulation of HLA-DR was not explained by altered cathepsin S activity. Mature, peptide-loaded HLA-DR molecules were retained within cells, as assessed by the proportion of SDS-stable HLA-DR dimers. A block in egress was implicated, as endocytosis of surface HLA-DR was not increased. Immunofluorescence microscopy corroborated the intracellular retention of HLA-DR and revealed markedly fewer HLA-DR-positive dendritic projections in infected mature LC. Unexpectedly, light microscopic analyses showed a dramatic loss of the dendrites themselves and immunofluorescence revealed that cytoskeletal elements crucial for the formation and maintenance of dendrites are disrupted in viral Ag-positive cells. Consistent with these dendrite effects, HCMV-infected mature LC exhibit markedly reduced chemotaxis in response to lymphoid chemokines. Thus, HCMV impedes MHC class II molecule trafficking, dendritic projections, and migration of mature LC. These changes likely contribute to the reduced activation of CD4+ T cells by HCMV-infected mature LC.
Salmonella typhimurium Coordinately Regulates FliC Location and Reduces Dendritic Cell Activation and Antigen Presentation to CD4+ T cells
Authors: Alaniz Robert C. , Cummings Lisa A. , Bergman Molly A. , Rassoulian-Barrett Sara L. , Cookson Brad T. 
Published: April 2014

Abstract
During infection, Salmonella transitions from an extracellular-phase (STEX, growth outside host cells) to an intracellular-phase (STIN, growth inside host cells): changes in gene expression mediate survival in the phagosome and modifies LPS and outer membrane protein expression, including altered production of FliC, an Ag recognized by immune CD4+ T cells. Previously, we demonstrated that systemic STIN bacteria repress FliC below the activation threshold of FliC-specific T cells. In this study, we tested the hypothesis that changes in FliC compartmentalization and bacterial responses triggered during the transition from STEX to STIN combine to reduce the ability of APCs to present FliC to CD4+ T cells. Approximately 50% of the Salmonella-specific CD4+ T cells from Salmonella-immune mice were FliC specific and produced IFN-γ, demonstrating the potent immunogenicity of FliC. FliC expressed by STEX bacteria was efficiently presented by splenic APCs to FliC-specific CD4+ T cells in vitro. However, STIN bacteria, except when lysed, expressed FliC within a protected intracellular compartment and evaded stimulation of FliC-specific T cells. The combination of STIN-mediated responses that reduced FliC bioavailability were overcome by dendritic cells (DCs), which presented intracellular FliC within heat-killed bacteria; however, this ability was abrogated by live bacterial infection. Furthermore, STIN bacteria, unlike STEX, limited DC activation as measured by increased MHC class II, CD86, TNF-α, and IL-12 expression. These data indicate that STIN bacteria restrict FliC bioavailability by Ag compartmentalization, and together with STIN bacterial responses, limit DC maturation and cytokine production. Together, these mechanisms may restrain DC-mediated activation of FliC-specific CD4+ T cells.
Role of N-Acetylglucosamine within Core Lipopolysaccharide of Several Species of Gram-Negative Bacteria in Targeting the DC-SIGN (CD209)
Authors: Zhang Pei , Snyder Scott , Feng Peter , Azadi Parastoo , Zhang Shusheng , Bulgheresi Silvia , Sanderson Kenneth E. , He Johnny , Klena John , Chen Tie 
Published: April 2014

Abstract
Our recent studies have shown that the dendritic cell-specific ICAM nonintegrin CD209 (DC-SIGN) specifically binds to the core LPS of Escherichia coli K12 (E. coli), promoting bacterial adherence and phagocytosis. In this current study, we attempted to map the sites within the core LPS that are directly involved in LPS-DC-SIGN interaction. We took advantage of four sets of well-defined core LPS mutants, which are derived from E. coli, Salmonella enterica serovar Typhimurium, Neisseria gonorrhoeae, and Haemophilus ducreyi and determined interaction of each of these four sets with DC-SIGN. Our results demonstrated that N-acetylglucosamine (GlcNAc) sugar residues within the core LPS in these bacteria play an essential role in targeting the DC-SIGN receptor. Our results also imply that DC-SIGN is an innate immune receptor and the interaction of bacterial core LPS and DC-SIGN may represent a primeval interaction between Gram-negative bacteria and host phagocytic cells.
Chlamydia trachomatis Infection Alters the Development of Memory CD8+ T Cells
Authors: Loomis Wendy P. , Starnbach Michael N. 
Published: April 2014

Abstract
The obligate intracellular bacterium Chlamydia trachomatis is the most common cause of bacterial sexually transmitted disease in the United States and the leading cause of preventable blindness worldwide. Prior exposure to C. trachomatis has been shown to provide incomplete protection against subsequent infection. One possible explanation for the limited immunity afforded by prior C. trachomatis infection is poor activation of Chlamydia-specific memory CD8+ T cells. In this study, we examined the development of CD8+ memory T cell responses specific for the Chlamydia Ag CrpA. The percentage of CrpA63–71-specific T cells expressing an effector memory T cell phenotype (IL-7R+ CD62low) was dramatically diminished in mice immunized with C. trachomatis, compared with mice immunized with vaccinia virus expressing the CrpA protein. These alterations in memory T cell development were correlated with a significant reduction in the capacity of convalescent mice to mount an enhanced recall response to Chlamydia Ags, compared with the primary response. CrpA-specific memory T cells primed during VacCrpA infection also failed to respond to a challenge with Chlamydia. We therefore investigated whether C. trachomatis infection might have a global inhibitory effect on CD8+ T cell activation by coinfecting mice with C. trachomatis and Listeria monocytogenes and we found that the activation of Listeria-specific naive and memory CD8+ T cells was reduced in the presence of C. trachomatis. Together, these results suggest that Chlamydia is able to alter the development of CD8+ T cell responses during both primary and secondary infection, perhaps accounting for the incomplete protection provided by prior Chlamydia infection.
Neutrophil Signaling Pathways Activated by Bacterial DNA Stimulation
Authors: Alvarez María E. , Bass Juan I. Fuxman , Geffner Jorge R. , Calotti Paula X. Fernández , Costas Mónica , Coso Omar A. , Gamberale Romina , Vermeulen Mónica E. , Salamone Gabriela , Martinez Diego , Tanos Tamara , Trevani Analía S. 
Published: April 2014

Abstract
We have previously shown that bacterial DNA activates human neutrophils in a CpG-independent manner. In this study, we have characterized the signaling pathways involved in the activation mechanism. We found that p38 MAPK, ERK1/2, and JNK pathways, as well as the PI3K/Akt pathway, are activated by bacterial DNA. We also determined that bacterial DNA induces NF-κB and AP-1 activation. When analyzing the role of these pathways on neutrophil functions, we observed that up-regulation of CD11b triggered by bacterial DNA was decreased by pharmacological inhibitors of the p38 MAPK, ERK1/2, and JNK, whereas stimulation of IL-8 release was dependent on p38, ERK1/2, and NF-κB. Moreover, we found that IL-8 production was markedly enhanced by inhibition of JNK, suggesting that this pathway negatively modulates NF-κB-dependent transcription. We also observed that bacterial DNA stimulated IL-1R-associated kinase-1 kinase activity and its partial degradation. Finally, we determined that bacterial DNA stimulated CD11b up-regulation in TLR9−/− but not in MyD88−/− mouse neutrophils, supporting that bacterial DNA induces neutrophil activation through a TLR9-independent and MyD88-dependent pathway.
Distinct In Vivo Roles of Colony-Stimulating Factor-1 Isoforms in Renal Inflammation
Authors: Jang Mei-Huei , Herber Deborah M. , Jiang Xinnong , Nandi Sayan , Dai Xu-Ming , Zeller Geraldine , Stanley E. Richard , Kelley Vicki R. 
Published: April 2014

Abstract
CSF-1, the major regulator of macrophage (Mφ) development, has three biologically active isoforms: a membrane-spanning, cell surface glycoprotein, a secreted glycoprotein, and a secreted proteoglycan. We hypothesized that there are shared and unique roles of individual CSF-1 isoforms during renal inflammation. To test this, we evaluated transgenic mice only expressing the cell surface or precursors of the secreted CSF-1 isoforms for Mφ accumulation, activation, and Mφ-mediated tubular epithelial cell (TEC) apoptosis during unilateral ureteral obstruction. The only difference between secreted proteoglycan and secreted glycoprotein CSF-1 isoforms is the presence (proteoglycan) or absence (glycoprotein) of an 18-kDa chondroitin sulfate glycosaminoglycan. We report that 1) cell surface CSF-1 isoform is sufficient to restore Mφ accumulation, activation, and TEC apoptosis to wild-type levels and is substantially more effective than the secreted CSF-1 isoforms; 2) the chondroitin sulfate glycosaminoglycan facilitates Mφ accumulation, activation, and TEC apoptosis; 3) increasing the level of secreted proteoglycan CSF-1 in serum amplifies renal inflammation; and 4) cell-cell contact is required for Mφ to up-regulate CSF-1-dependent expression of IFN-γ. Taken together, we have identified central roles for the cell surface CSF-1 and the chondroitin sulfate chain on secreted proteoglycan CSF-1 during renal inflammation.
Serum Amyloid A Is an Endogenous Ligand That Differentially Induces IL-12 and IL-23
Authors: He Rong , Shepard Larry W. , Chen Jia , Pan Zhixing K. , Ye Richard D. 
Published: April 2014

Abstract
The acute-phase proteins, C-reactive protein and serum amyloid A (SAA), are biomarkers of infection and inflammation. However, their precise role in immunity and inflammation remains undefined. We report in this study a novel property of SAA in the differential induction of Th1-type immunomodulatory cytokines IL-12 and IL-23. In peripheral blood monocytes and the THP-1 monocytic cell line, SAA induces the expression of IL-12p40, a subunit shared by IL-12 and IL-23. SAA-stimulated expression of IL-12p40 was rapid (≤4 h), sustainable (≥20 h), potent (up to 3380 pg/ml/106 cells in 24 h), and insensitive to polymyxin B treatment. The SAA-stimulated IL-12p40 secretion required de novo protein synthesis and was accompanied by activation of the transcription factors NF-κB and C/EBP. Expression of IL-12p40 required activation of the p38 MAPK and PI3K. Interestingly, the SAA-induced IL-12p40 production was accompanied by a sustained expression of IL-23p19, but not IL-12p35, resulting in preferential secretion of IL-23, but not IL-12. These results identify SAA as an endogenous ligand that potentially activates the IL-23/IL-17 pathway and present a novel mechanism for regulation of inflammation and immunity by an acute-phase protein.
Complement Activation Contributes to Both Glomerular and Tubulointerstitial Damage in Adriamycin Nephropathy in Mice
Authors: Turnberg Daniel , Lewis Margarita , Moss Jill , Xu Yuanyuan , Botto Marina , Cook H. Terence 
Published: April 2014

Abstract
Adriamycin nephropathy is a model of focal segmental glomerulosclerosis, characterized by proteinuria and progressive glomerulosclerosis and tubulointerstitial damage. In this study, we examined the role of complement in the etiology of adriamycin nephropathy in mice. We used mice deficient in C1q, factor D, C3, and CD59, and compared them with strain-matched controls. C3 deposition occurred in the glomeruli of wild-type mice as early as 48 h following a single i.v. injection of adriamycin. C3-deficient mice developed significantly less proteinuria and less podocyte injury at day 3 postadriamycin than controls, suggesting that complement is important in mediating the early podocyte injury. At later time points, C3-deficient mice were protected from glomerulosclerosis, tubulointerstitial injury, and renal dysfunction. Factor D-deficient mice were also protected from renal disease, confirming the importance of alternative pathway activation in this model. In contrast, C1q-deficient mice developed similar disease to controls, indicating that the complement cascade was not activated via the classical pathway. CD59-deficient mice, which lack adequate control of C5b-9 formation, developed significantly worse histological and functional markers of renal disease than controls. Interestingly, although more C9 deposited in glomeruli of CD59-deficient mice than controls, in neither group was tubulointerstitial C9 staining apparent. We have demonstrated for the first time that alternative pathway activation of complement plays an important role in mediating the initial glomerular damage in this in vivo model of focal segmental glomerulosclerosis. Lack of CD59, which regulates the membrane attack complex, led to greater glomerular and tubulointerstitial injury.
Vascular Endothelial Growth Factor Receptor 2-Based DNA Immunization Delays Development of Herpetic Stromal Keratitis by Antiangiogenic Effects
Authors: Kim Bumseok , Suvas Susmit , Sarangi Pranita P. , Lee Sujin , Reisfeld Ralph A. , Rouse Barry T. 
Published: April 2014

Abstract
Stromal keratitis (SK) is an immunoinflammatory eye lesion caused by HSV-1 infection. One essential step in the pathogenesis is neovascularization of the normally avascular cornea, a process that involves the vascular endothelial growth factor (VEGF) family of proteins. In this report, we targeted the proliferating vascular endothelial cells expressing VEGFR-2 in the SK cornea by immunization with recombinant Salmonella typhimurium containing a plasmid encoding murine VEGFR-2. This form of DNA immunization resulted in diminished angiogenesis and delayed development of SK caused by HSV-1 infection and also reduced angiogenesis resulting from corneal implantation with rVEGF. CTL responses against endothelial cells expressing VEGFR-2 were evident in the VEGFR-2-immunized group and in vivo CD8+ T cell depletion resulted in the marked reduction of the antiangiogenic immune response. These results indicate a role for CD8+ T cells in the antiangiogenic effects. Our results may also imply that the anti-VEGFR-2 vaccination approach might prove useful to control pathological ocular angiogenesis and its consequences.