1,835 research outputs found
Negotiation in strategy making teams : group support systems and the process of cognitive change
This paper reports on the use of a Group Support System (GSS) to explore at a micro level some of the processes manifested when a group is negotiating strategy-processes of social and psychological negotiation. It is based on data from a series of interventions with senior management teams of three operating companies comprising a multi-national organization, and with a joint meeting subsequently involving all of the previous participants. The meetings were concerned with negotiating a new strategy for the global organization. The research involved the analysis of detailed time series data logs that exist as a result of using a GSS that is a reflection of cognitive theory
An unexpected major role for proteasome-catalyzed peptide splicing in generation of T cell epitopes: Is there relevance for vaccine development?
Efficient and safe induction of CD8(+) T cell responses is a desired characteristic of vaccines against intracellular pathogens. To achieve this, a new generation of safe vaccines is being developed accommodating single, dominant antigens of pathogens of interest. In particular, the selection of such antigens is challenging, since due to HLA polymorphism the ligand specificities and immunodominance hierarchies of pathogen-specific CD8(+) T cell responses differ throughout the human population. A recently discovered mechanism of proteasome-mediated CD8(+) T cell epitope generation, i.e., by protea-some-catalyzed peptide splicing (PCPS), expands the pool of peptides and antigens, presented by MHC class I HLA molecules. On the cell surface, one-third of the presented self-peptides are generated by PCPS, which coincides with one-fourth in terms of abundance. Spliced epitopes are targeted by CD8(+) T cell responses during infection and, like non-spliced epitopes, can be identified within antigen sequences using a novel in silico strategy. The existence of spliced epitopes, by enlarging the pool of peptides available for presentation by different HLA variants, opens new opportunities for immunotherapies and vaccine design
Reduced TCR-dependent activation through citrullination of a T-cell epitope enhances Th17 development by disruption of the STAT3/5 balance
Citrullination is a post-translational modification of arginine that commonly occurs in
inflammatory tissues. Because T-cell receptor (TCR) signal quantity and quality can regulate
T-cell differentiation, citrullination within a T-cell epitope has potential implications
for T-cell effector function. Here, we investigated how citrullination of an immunedominant
T-cell epitope affected Th17 development. Murine na¨ıve CD4+ T cells with a transgenic
TCR recognising p89-103 of the G1 domain of aggrecan (agg) were co-cultured with
syngeneic bone marrow-derived dendritic cells (BMDC) presenting the native or citrullinated
peptides. In the presence of pro-Th17 cytokines, the peptide citrullinated on residue
93 (R93Cit) significantly enhanced Th17 development whilst impairing the Th2 response,
compared to the native peptide. T cells responding to R93Cit produced less IL-2, expressed
lower levels of the IL-2 receptor subunit CD25, and showed reduced STAT5 phosphorylation,
whilst STAT3 activation was unaltered. IL-2 blockade in native p89-103-primed
T cells enhanced the phosphorylated STAT3/STAT5 ratio, and concomitantly enhanced
Th17 development. Our data illustrate how a post-translational modification of a TCR
contact point may promote Th17 development by altering the balance between STAT5
and STAT3 activation in responding T cells, and provide new insight into how protein
citrullination may influence effector Th-cell development in inflammatory disorders
The anti-inflammatory mechanisms of Hsp70
Immune responses to heat shock proteins (Hsp) develop in virtually all inflammatory diseases; however, the significance of such responses is only now becoming clear. In experimental disease models, Hsp administration can prevent or arrest inflammatory damage, and in initial clinical trials in patients with chronic inflammatory diseases, Hsp peptides have been shown to promote the production of anti-inflammatory cytokines, indicating immunoregulatory potential of Hsp. Therefore, the presence of immune responses to Hsp in inflammatory diseases can be seen as an attempt of the immune system to correct the inflammatory condition. Hsp70 can modulate inflammatory responses in models of arthritis, colitis and graft rejection, and the mechanisms underlying this effect are now being elucidated. Incubation with microbial Hsp70 was seen to induce tolerogenic dendritic cells (DCs) and to promote a suppressive phenotype in myeloid-derived suppressor cells and monocytes. These DC could induce regulatory T cells (Tregs), independently of the antigens they presented. Some Hsp70 family members are associated with autophagy, leading to a preferential uploading of Hsp70 peptides in MHC class II molecules of stressed cells. Henceforth, conserved Hsp70 peptides may be presented in these situations and constitute targets of Tregs, contributing to downregulation of inflammation. Finally, an interfering effect in multiple intracellular inflammatory signaling pathways is also known for Hsp70. Altogether it seems attractive to use Hsp70, or its derivative peptides, for modulation of inflammation. This is a physiological immunotherapy approach, without the immediate necessity of defining disease-specific auto-antigens. In this article, we present the evidence on anti-inflammatory effects of Hsp70 and discuss the need for experiments that will be crucial for the further exploration of the immunosuppressive potential of this protein
Cellular host transcriptional responses to influenza A virus in chicken tracheal organ cultures differ from responses in in vivo infected trachea
N=4 Super-Yang-Mills Theory, QCD and Collider Physics
We review how (dimensionally regulated) scattering amplitudes in N=4
super-Yang-Mills theory provide a useful testing ground for perturbative QCD
calculations relevant to collider physics, as well as another avenue for
investigating the AdS/CFT correspondence. We describe the iterative relation
for two-loop scattering amplitudes in N=4 super-Yang-Mills theory found in C.
Anastasiou et al., Phys. Rev. Lett. 91:251602 (2003), and discuss recent
progress toward extending it to three loops.Comment: 17 pages, 9 figures. Talk presented by LD at Strings 200
Early host responses to avian influenza A virus are prolonged and enhanced at transcriptional level depending on maturation of the immune system
Reduced immune reaction prevents immunopathology after challenge with avian influenza virus: A transcriptomics analysis of adjuvanted vaccines
To gain more insight in underlying mechanisms correlating to protection against avian influenza virus (AIV) infection, we investigated correlates of protection after AIV H9N2 infection and studied the contribution of different adjuvants to a protective response at host transcriptional level. One-day-old chickens were immunised with inactivated H9N2 supplemented with w/o, Al(OH)3, CpG or without adjuvant. Two weeks later, birds were homologously challenged and at 1-4 days post challenge (d.p.c.) trachea and lung were collected. Birds immunised with H9N2+w/o or H9N2+Al(OH)3 were protected against challenge infection and had lower viral RNA expression, less immune related genes induced after challenge, a lower amplitude of change of gene expression and smaller cellular influxes compared to the higher and prolonged gene expression in unprotected birds. We show that a limited number of differentially expressed genes correlates with reduced immune activation and subsequently reduced immunopathology after challenge with AIV
An Unexpected Major Role for Proteasome-Catalyzed Peptide Splicing in Generation of T Cell Epitopes:Is There Relevance for Vaccine Development?
Efficient and safe induction of CD8+ T cell responses is a desired characteristic of vaccines against intracellular pathogens. To achieve this, a new generation of safe vaccines is being developed accommodating single, dominant antigens of pathogens of interest. In particular, the selection of such antigens is challenging, since due to HLA polymorphism the ligand specificities and immunodominance hierarchies of pathogen-specific CD8+ T cell responses differ throughout the human population. A recently discovered mechanism of proteasome-mediated CD8+ T cell epitope generation, i.e., by proteasome-catalyzed peptide splicing (PCPS), expands the pool of peptides and antigens, presented by MHC class I HLA molecules. On the cell surface, one-third of the presented self-peptides are generated by PCPS, which coincides with one-fourth in terms of abundance. Spliced epitopes are targeted by CD8+ T cell responses during infection and, like non-spliced epitopes, can be identified within antigen sequences using a novel in silico strategy. The existence of spliced epitopes, by enlarging the pool of peptides available for presentation by different HLA variants, opens new opportunities for immunotherapies and vaccine design.</p
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