| 1. |
- Badolati, Isabella, et al.
(author)
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Staphylococcus aureus-derived factors promote human Th9 cell polarization and enhance a transcriptional program associated with allergic inflammation
- 2023
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In: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 53:3
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Journal article (peer-reviewed)abstract
- T helper (Th) 9 cells, characterized by robust secretion of IL-9, have been increasingly associated with allergic diseases. However, whether and how Th9 cells are modulated by environmental stimuli remains poorly understood. In this study, we show that in vitro exposure of human PBMCs or isolated CD4 T-cells to Staphylococcus (S.) aureus-derived factors, including its toxins, potently enhances Th9 cell frequency and IL-9 secretion. Furthermore, as revealed by RNA sequencing analysis, S. aureus increases the expression of Th9-promoting factors at the transcriptional level, such as FOXO1, miR-155, and TNFRSF4. The addition of retinoic acid (RA) dampens the Th9 responses promoted by S. aureus and substantially changes the transcriptional program induced by this bacterium, while also altering the expression of genes associated with allergic inflammation. Together, our results demonstrate a strong influence of microbial and dietary factors on Th9 cell polarization, which may be important in the context of allergy development and treatment.
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| 2. |
- Chen, Yunying, et al.
(author)
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A regulatory role for macrophage class A scavenger receptors in TLR4-mediated LPS responses.
- 2010
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In: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 40:5, s. 1451-60
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Journal article (peer-reviewed)abstract
- Recognition of microbial components by TLR, key sensors of infection, leads to induction of inflammatory responses. We found that, in vivo, TLR4 engagement by LPS induces up-regulation of the class A scavenger receptors (SR) macrophage receptor with a collagenous structure (MARCO) and SR-A, which occurs, at least in the case of MARCO, via both MyD88-dependent and -independent pathways. When challenging mice with a low dose of LPS followed by a high dose, class A SR-deficient mice showed a higher survival rate than WT mice. This was paired with increased production of IL-10 and anti-LPS Ab, as well as increased activation status of marginal zone B cells. However, the receptors were not crucial for survival when challenging mice i.p. with Neisseria meningitidis or Listeria monocytogenes, but they were found to contribute to microbial capture and clearance. This indicates physiological significance for the up-regulation of class A SR during early stages of bacterial infection. Thus, we believe that we have revealed a mechanism where SR regulate the activation status of the immune system and are involved in balancing a proper immune response to infection. This regulation could also be important in maintaining tolerance since these receptors have been shown to be involved in regulation of self-reactivity.
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| 3. |
- Högstrand, Kari, et al.
(author)
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Transformation of mature mouse B cells into malignant plasma cells in vitro via introduction of defined genetic elements
- 2019
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In: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 49:3, s. 454-461
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Journal article (peer-reviewed)abstract
- An experimental system where defined alterations in gene function or gene expression levels in primary B cells would result in the development of transformed plasma cells in vitro would be useful in order to facilitate studies of the underlying molecular mechanisms of plasma cell malignancies. Here, such a system is described in which primary murine B cells rapidly become transformed into surface CD138(+), IgM(-/low), CD19(-) IgM-secreting plasma cells as a result of expression of the transcription factors IRF4 and MYC together with simultaneous expression of BMI1, mutated p53 or silencing of p19(Arf), and suppression of intrinsic apoptosis through expression of BCLXL. Analysis of gene expression patterns revealed that this combination of transforming genes resulted in expression of a number of genes previously associated with terminally differentiated B cells (plasma cells) and myeloma cells, whereas many genes associated with mature B cells and B-cell lymphomas were not expressed. Upon transplantation, the transformed cells preferentially localized to the bone marrow, presenting features of a plasma cell malignancy of the IgM isotype. The present findings may also be applicable in the development of novel methods for production of monoclonal antibodies.
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| 4. |
- Palma, Carla, et al.
(author)
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Mycobacterium tuberculosis PstS1 amplifies IFN-gamma and induces IL-17/IL-22 responses by unrelated memory CD4(+) T cells via dendritic cell activation
- 2013
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In: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 43:9, s. 2386-2397
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Journal article (peer-reviewed)abstract
- The immunological mechanisms that modulate protection during Mycobacterium tuberculosis (Mtb) infection or vaccination are not fully understood. Secretion of IFN- and, to a lesser extent, of IL-17 by CD4(+) T cells plays a major role both in protection and immunopathology. Few MtbAgs interacting with DCs affect priming, activation, and regulation of Ag-unrelated CD4(+) T-cell responses. Here we demonstrate that PstS1, a 38 kDa-lipoprotein of Mtb, promotes Ag-independent activation of memory T lymphocytes specific for Ag85B or Ag85A, two immunodominant protective Ags of Mtb. PstS1 expands CD4(+) and CD8(+) memory T cells, amplifies secretion of IFN- and IL-22 and induces IL-17 production by effector memory cells in an Ag-unrelated manner in vitro and in vivo. These effects were mediated through the stimulation of DCs, particularly of the CD8(-) subtype, which respond to PstS1 by undergoing phenotypic maturation and by secreting IL-6, IL-1 and, to a lower extent, IL-23. IL-6 secretion by PstS1-stimulated DCs was required for IFN-, and to a lesser extent for IL-22 responses by Ag85B-specific memory T cells. These results may open new perspectives for immunotherapeutic strategies to control Th1/Th17 immune responses in Mtb infections and in vaccinations against tuberculosis.
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| 5. |
- Wang, Xiao, et al.
(author)
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CD46 accelerates macrophage-mediated host susceptibility to meningococcal sepsis in a murine model
- 2017
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In: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 47:1, s. 119-130
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Journal article (peer-reviewed)abstract
- CD46, a membrane cofactor expressed on all nucleated human cells, plays an essential role in suppressing autoimmune reactions and protecting host cells from complement-mediated attack. Human transgenic CD46 homozygousmice (CD46(+/+)) are prone to lethal sepsis upon infection with Neisseria meningitidis (N. meningitidis). However, the underlying mechanisms are poorly understood. Here, we determined thatCD46(+/+) mice produce large numbers of M1 type macrophages with enhanced surface expression of MHC II and production of pro-inflammatory mediators such as IL-6, TNF, IL-12, and IL-1 beta In the presence of M-CSF or GM-CSF, CD46 signaling enhances monocyte-macrophage differentiation. Additionally, CD46(+/+) macrophages rapidly undergo apoptosis upon LPS challenge or meningococcal infection, which could contribute to uncontrolled bacterial dissemination in vivo. Adoptive transfer of CD46(+/+) peritoneal macrophages aggravated septic responses in wild-type mice, but the depletion of macrophages partially alleviated septic reactions in CD46(+/+) mice after N. meningitidis infection. Our findings reveal a novel role of CD46 in accelerating inflammatory responses upon meningococcal infection or LPS stimulation by regulating the functional polarization and survival of macrophages.
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