scholarly journals Distinct mechanisms of neonatal tolerance induced by dendritic cells and thymic B cells.

1991 ◽  
Vol 173 (3) ◽  
pp. 549-559 ◽  
Author(s):  
M Inaba ◽  
K Inaba ◽  
M Hosono ◽  
T Kumamoto ◽  
T Ishida ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
B Cells ◽  
Cell Types ◽  
Cell Sorter ◽  
Histocompatibility Complex ◽  
Different Types ◽  
Induced Tolerance ◽  
Antigen Presenting

To assess the role of different types of antigen-presenting cells (APC) in the induction of tolerance, we isolated B cells, macrophages, and dendritic cells from thymus and spleen, and injected these into neonatal BALB/c mice across an Mls-1 antigenic barrier. One week after injection of APC from Mls-1-incompatible mice or from control syngeneic mice, we measured the number of thymic, Mls-1a-reactive, V beta 6+ T cells and the capacity of thymocytes to induce a graft-vs.-host (GVH) reaction in popliteal lymph nodes of Mls-1a mice. Injection of thymic but not spleen B cells deleted thymic, Mls-1a-reactive V beta 6+ T cells and induced tolerance in the GVH assay. The thymic B cells were primarily of the CD5+ type, and fluorescence-activated cell sorter-purified CD5+ thymic B cells were active. Injection of dendritic cells from spleen or thymus also induced tolerance, but the V beta 6 cells were anergized rather than deleted. Macrophages from thymus did not induce tolerance. Dendritic cells and thymic B cells were also effective in inducing tolerance even when injected into Mls-, major histocompatibility complex-incompatible, I-E- mice, but only thymic B cells depleted V beta 6-expressing T cells. Therefore, different types of bone marrow-derived APC have different capacities for inducing tolerance, and the active cell types (dendritic cells and CD5+ thymic B cells) can act by distinct mechanisms.

The paracaspase MALT1 in psoriasis

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Stephan Hailfinger ◽  
Klaus Schulze-Osthoff
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Transcription Factors ◽  
Skin Disease ◽  
Cell Types ◽  
Cytokine Receptors ◽  
Molecular Scaffold ◽  
Therapeutic Implications ◽  
Stimulation Of

Abstract Psoriasis is a frequent autoimmune-related skin disease, which involves various cell types such as T cells, keratinocytes and dendritic cells. Genetic variations, such as mutations of CARD14, can promote the development of the disease. CARD14 mutations as well as the stimulation of immune and cytokine receptors activate the paracaspase MALT1, a potent activator of the transcription factors NF-κB and AP-1. The disease-promoting role of MALT1 for psoriasis is mediated by both its protease activity as well as its molecular scaffold function. Here, we review the importance of MALT1-mediated signaling and its therapeutic implications in psoriasis.

scholarly journals Follicular dendritic cells help resting B cells to become effective antigen-presenting cells: induction of B7/BB1 and upregulation of major histocompatibility complex class II molecules.

1993 ◽  
Vol 178 (6) ◽  
pp. 2055-2066 ◽  
Author(s):  
M H Kosco-Vilbois ◽  
D Gray ◽  
D Scheidegger ◽  
M Julius
Keyword(s):  
Dendritic Cells ◽  
Major Histocompatibility Complex ◽  
B Cells ◽  
Major Histocompatibility Complex Class ◽  
B Cell ◽  
Antigen Presenting Cells ◽  
Follicular Dendritic Cells ◽  
Complex Class ◽  
Histocompatibility Complex ◽  
Antigen Presenting

This study was designed to investigate whether follicular dendritic cells (FDC) can activate B cells to a state in which they can function as effective antigen-presenting cells (APC). High buoyant density (i.e., resting) B cells specific for 2,4-dinitro-fluorobenzene (DNP) were incubated with DNP-ovalbumin (OVA) bearing FDC, after which their capacity to process and present to an OVA-specific T cell clone was assessed. The efficacies of alternative sources of antigen and activation signals in the induction of B cell APC function were compared with those provided by FDC. Only FDC and Sepharose beads coated with anti-immunoglobulin (Ig)kappa monoclonal antibody provided the necessary stimulus. FDC carrying inappropriate antigens also induced B cell APC function in the presence of exogenous DNP-OVA. However, in circumstances where soluble DNP-OVA was limiting, FDC bearing complexes containing DNP, which could crosslink B cell Ig receptors, induced the most potent APC function. Analysis by flow cytometry revealed that within 24 h of coculture with FDC, a significant percentage of B cells increased in size and expressed higher levels of major histocompatibility complex class II. By 48 h, an upregulation of the costimulatory molecule, B7/BB1, occurred, but only when exposed to the FDC bearing DNP. Taken together, the results demonstrate that FDC have the capacity to activate resting B cells to a state in which they can function as APC for T cells. The stimuli that FDC provide may include: (a) an antigen-dependent signal that influences the upregulation of B7/BB1; and (b) possibly a signal independent of crosslinking mIg that results in Ig internalization. The relevance of these findings to the formation of germinal centers and maintenance of the humoral response is discussed.

Infection and immunity

2021 ◽  
pp. 853-920
Keyword(s):  
Major Histocompatibility Complex ◽  
Immune System ◽  
Cell Types ◽  
The Body ◽  
Acquired Immunity ◽  
Histocompatibility Complex ◽  
Repair Mechanisms ◽  
Antigen Presenting ◽  
Different Cell Types

‘Infection and immunity’ considers the response of the body to pathogens, such as bacteria, viruses, prions, fungi, and parasites, which are discussed in terms of their nature, life cycle, and modes of infection. The role of the immune system in defence against infection is discussed, including innate and adaptive (acquired) immunity, antigens, the major histocompatibility complex, and the different cell types involved (antigen-presenting cells, T-cells, and B-cells). The mechanisms and cellular basis of inflammation are considered, as are post-infection repair mechanisms, and pathologies of the immune system such as hypersensitivity, autoimmunity and transplantations, and immunodeficiency (both primary and secondary to other diseases).

scholarly journals T Cell Accumulation in B Cell Follicles Is Regulated by Dendritic Cells and Is Independent of B Cell Activation

2003 ◽  
Vol 197 (2) ◽  
pp. 195-206 ◽  
Author(s):  
Simon Fillatreau ◽  
David Gray
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Activation ◽  
B Cell Activation ◽  
Cell Accumulation ◽  
Antigen Presenting ◽  
Deficient Mice

We investigated the mechanism of CD4 T cell accumulation in B cell follicles after immunization. Follicular T cell numbers were correlated with the number of B cells, indicating B cell control of the niche that T cells occupy. Despite this, we found no role for B cells in the follicular migration of T cells. Instead, T cells are induced to migrate into B cell follicles entirely as a result of interaction with dendritic cells (DCs). Migration relies on CD40-dependent maturation of DCs, as it did not occur in CD40-deficient mice but was reconstituted with CD40+ DCs. Restoration was not achieved by the activation of DCs with bacterial activators (e.g., lipopolysaccharide, CpG), but was by the injection of OX40L–huIgG1 fusion protein. Crucially, the up-regulation of OX40L (on antigen-presenting cells) and CXCR-5 (on T cells) are CD40-dependent events and we show that T cells do not migrate to follicles in immunized OX40-deficient mice.

scholarly journals Exogenous antigens gain access to the major histocompatibility complex class I processing pathway in B cells by receptor-mediated uptake.

1996 ◽  
Vol 184 (3) ◽  
pp. 1179-1184 ◽  
Author(s):  
Y Ke ◽  
J A Kapp
Keyword(s):  
Dendritic Cells ◽  
Major Histocompatibility Complex ◽  
B Cells ◽  
Major Histocompatibility Complex Class ◽  
Class I ◽  
Complex Class ◽  
Receptor Mediated Endocytosis ◽  
Histocompatibility Complex ◽  
Antigen Presenting ◽  
Gain Access

Professional antigen-presenting cells, such as macrophages, dendritic cells, or B cells, take up soluble, exogenous antigens (Ags) and process them through the class II pathway. Several reports have shown that phagocytic macrophages also process particulate or soluble forms of exogenous Ag via the class I pathway. By contrast, B cells normally do not process soluble, exogenous Ag by way of the class I pathway unless Ags are directly introduced into the cytoplasm. Here we report that B cells present exogenous Ag via the class I pathway when Ags are taken up by receptor-mediated endocytosis. Thus, specialized methods of Ag uptake such as phagocytosis or receptor-mediated endocytosis deliver exogenous Ag into the class I pathway of Ag processing and presentation.

scholarly journals Presentation of Toxoplasma gondii Antigens via the Endogenous Major Histocompatibility Complex Class I Pathway in Nonprofessional and Professional Antigen-Presenting Cells

2007 ◽  
Vol 75 (11) ◽  
pp. 5200-5209 ◽  
Author(s):  
Florence Dzierszinski ◽  
Marion Pepper ◽  
Jason S. Stumhofer ◽  
David F. LaRosa ◽  
Emma H. Wilson ◽  
...  
Keyword(s):  
T Cells ◽  
Major Histocompatibility Complex ◽  
T Cell ◽  
Antigen Processing ◽  
Cell Types ◽  
T Cell Response ◽  
Complex Class ◽  
Mhc I ◽  
Histocompatibility Complex ◽  
Antigen Presenting

ABSTRACT Challenge with the intracellular protozoan parasite Toxoplasma gondii induces a potent CD8+ T-cell response that is required for resistance to infection, but many questions remain about the factors that regulate the presentation of major histocompatibility complex class I (MHC-I)-restricted parasite antigens and about the role of professional and nonprofessional accessory cells. In order to address these issues, transgenic parasites expressing ovalbumin (OVA), reagents that track OVA/MHC-I presentation, and OVA-specific CD8+ T cells were exploited to compare the abilities of different infected cell types to stimulate CD8+ T cells and to define the factors that contribute to antigen processing. These studies reveal that a variety of infected cell types, including hematopoietic and nonhematopoietic cells, are capable of activating an OVA-specific CD8+ T-cell hybridoma, and that this phenomenon is dependent on the transporter associated with antigen processing and requires live T. gondii. Several experimental approaches indicate that T-cell activation is a consequence of direct presentation by infected host cells rather than cross-presentation. Surprisingly, nonprofessional antigen-presenting cells (APCs) were at least as efficient as dendritic cells at activating this MHC-I-restricted response. Studies to assess whether these cells are involved in initiation of the CD8+ T-cell response to T. gondii in vivo show that chimeric mice expressing MHC-I only in nonhematopoietic compartments are able to activate OVA-specific CD8+ T cells upon challenge. These findings associate nonprofessional APCs with the initial activation of CD8+ T cells during toxoplasmosis.

scholarly journals Myeloid and Plasmacytoid Dendritic Cells and Cancer – New Insights

2019 ◽  
Vol 7 (19) ◽  
pp. 3324-3340 ◽  
Author(s):  
Maya Gulubova ◽  
Koni Vancho Ivanova ◽  
Mehmed Hadzhi ◽  
Dimitur Chonov ◽  
Maria Magdalena Ignatova ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Immune Responses ◽  
Cell Types ◽  
Tumour Microenvironment ◽  
Mhc I ◽  
Cross Presentation ◽  
Adaptive Immune ◽  
Histocompatibility Complex ◽  
T Helpers

Dendritic cells (DCs) use effective mechanisms to combat antigens and to bring about adaptive immune responses through their ability to stimulate nӓive T cells. At present, four major cell types are categorised as DCs: Classical or conventional (cDCs), Plasmacytoid (pDCs), Langerhans cells (LCs), and monocyte-derived DCs (Mo-DCs). It was suggested that pDCs, CD1c+ DCs and CD141+ DCs in humans are equivalent to mouse pDCs, CD11b+ DCs and CD8α+ DCs, respectively. Human CD141+ DCs compared to mouse CD8α+ DCs have remarkable functional and transcriptomic similarities. Characteristic markers, transcription factors, toll-like receptors, T helpers (Th) polarisation, cytokines, etc. of DCs are discussed in this review. Major histocompatibility complex (MHC) I and II antigen presentation, cross-presentation and Th polarisation are defined, and the dual role of DCs in the tumour is discussed. Human DCs are the main immune cells that orchestrate the immune response in the tumour microenvironment.

scholarly journals Lymphocyte Changes in Severe COVID-19: Delayed Over-Activation of STING?

2020 ◽  
Vol 11 ◽  
Author(s):  
Jean-Marie Berthelot ◽  
Frédéric Lioté ◽  
Yves Maugars ◽  
Jean Sibilia
Keyword(s):  
T Cells ◽  
B Cells ◽  
Cd8 T Cells ◽  
Human Lymphocytes ◽  
Dna Damages ◽  
Human B Cells ◽  
Antigen Presenting ◽  
Microbial Dna ◽  
Th2 Differentiation

Upon recognition of microbial DNA or self-DNA, the cyclic-GMP-AMP synthase (cGAS) of the host catalyzes the production of the cyclic dinucleotide cGAMP. cGAMP is the main activator of STING, stimulator of interferon genes, leading to interferon synthesis through the STING-TBK1-IRF3 pathway. STING is also a hub for activation of NF-κB and autophagy. The present review details the striking similarities between T and B cell responses in severe coronavirus disease 2019 (COVID-19) and both animal or human models of STING gain of function (SAVI syndromes: STING-associated vasculopathy with onset in infancy). Those similarities may be further clues for a delayed activation of STING in severe COVID-19 patients, due to DNA damages following severe acute respiratory syndrome coronaviruses (SARS-CoV-2) infection and unusual role of STING in SARS-CoV-2 control. In early stages, Th2 differentiation are noticed in both severe COVID-19 and SAVI syndromes; then, CD4+ and CD8+ T cells functional exhaustion/senescent patterns due to TCR hyper-responsiveness are observed. T cell delayed over-responses can contribute to pneumonitis and delayed cytokine secretion with over-production of IL-6. Last, STING over-activation induces progressive CD4+ and CD8+ T lymphopenia in SAVI syndromes, which parallels what is observed in severe COVID-19. ACE2, the main receptor of SARS-CoV-2, is rarely expressed in immune cells, and it has not been yet proven that some human lymphocytes could be infected by SARS-CoV-2 through CD147 or CD26. However, STING, expressed in humans T cells, might be triggered following excessive transfer of cGAMP from infected antigen presenting cells into activated CD4+ and CD8+ T cells lymphocytes. Indeed, those lymphocytes highly express the cGAMP importer SLC19A1. Whereas STING is not expressed in human B cells, B cells counts are much less affected, either in COVID-19 or SAVI syndromes. The recognition of delayed STING over-activation in severe COVID-19 patients could prompt to target STING with specific small molecules inhibitors already designed and/or aspirin, which inhibits cGAS.

scholarly journals Independent Prognostic Potential of GNPNAT1 in Lung Adenocarcinoma

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Xiangyu Zheng ◽  
Yongwei Li ◽  
Chao Ma ◽  
Jinjun Zhang ◽  
Yanmin Zhang ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
B Cells ◽  
Lung Adenocarcinoma ◽  
Cd4 T Cells ◽  
Prognostic Value ◽  
Marker Genes ◽  
Immune Signatures ◽  
Cox Analysis

Background. Glucosamine-Phosphate N-Acetyltransferase 1 (GNPNAT1) is a critical enzyme in the biosynthesis of uridine diphosphate-N-acetylglucosamine. It has many important functions, such as protein binding, monosaccharide binding, and embryonic development and growth. However, the role of GNPNAT1 in lung adenocarcinoma (LUAD) remains unclear. Methods. In this study, we explored the expression pattern and prognostic value of GNPNAT1 in LUAD across TCGA and GEO databases and assessed its independent prognostic value via Cox analysis. LinkedOmics and GEPIA2 were applied to investigate coexpression and functional networks associated with GNPNAT1. The TIMER web tool was deployed to assess the correlation between GNPNAT1 and the main six types of tumor-infiltrating immune cells. Besides, the correlations between GNPNAT1 and the LUAD common genetic mutations, TMB, and immune signatures were examined. Results. GNPNAT1 was validated upregulated in tumor tissues in TCGA-LUAD and GEO cohorts. Moreover, in both TCGA and GEO cohorts, high GNPNAT1 expression was found to be associated with poor overall survival. Cox analysis showed that high GNPNAT1 expression was an independent risk factor for LUAD. Functional network analysis suggested that GNPNAT1 regulates cell cycle, ribosome, proteasome, RNA transport, and spliceosome signaling through pathways involving multiple cancer-related kinases and E2F family. In addition, GNPNAT1 correlated with infiltrating levels of B cells, CD4+ T cells, and dendritic cells. B cells and dendritic cells could predict the outcome of LUAD, and B cells and CD4+ T cells were significant independent risk factors. The TMB and mutations of KRAS, EGFR, STK11, and TP53 were correlated with GNPNAT1. At last, the correlation analysis showed GNPNAT1 correlated with most of the immune signatures we performed. Conclusion. Our findings showed that GNPNAT1 was correlated to the prognosis and immune infiltration of LUAD. In particular, the tight relationship between GNPNAT1 and B cell marker genes may be the epicenter of the immune response and one of the key factors affecting the prognosis. Our findings laid the foundation for further research on the immunomodulatory role of GNPNAT1 in LUAD.

scholarly journals Expression and functional significance of an additional ligand for CTLA-4

1993 ◽  
Vol 90 (23) ◽  
pp. 11054-11058 ◽  
Author(s):  
D J Lenschow ◽  
G H Su ◽  
L A Zuckerman ◽  
N Nabavi ◽  
C L Jellis ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
B Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Costimulatory Molecule ◽  
T Cell Proliferation ◽  
Antigen Presenting

Effective T-cell activation requires antigen/major histocompatibility complex engagement by the T-cell receptor complex in concert with one or more costimulatory molecules. Recent studies have suggested that the B7 molecule, expressed on most antigen presenting cells, functions as a costimulatory molecule through its interaction with CD28 on T cells. Blocking the CD28/B7 interaction with CTLA4Ig inhibits T-cell activation in vitro and induces unresponsiveness. We demonstrate that another molecule(s), termed B7-2, is expressed constitutively on dendritic cells, is differentially regulated on B cells, and costimulates naive T cells responding to alloantigen. B7-2 is up-regulated by lipopolysaccharide in < 6 hr and is maximally expressed on the majority of B cells by 24 hr. In contrast, B7 is detected only on a subset of activated B cells late (48 hr) after stimulation. In addition, Con A directly induces B7-2 but not B7 expression on B cells. Finally, although both anti-B7 monoclonal antibodies and CTLA4Ig blocked T-cell proliferation to antigen-expressing B7 transfectants, only CTLA4Ig had any significant inhibitory effect on T-cell proliferation to antigens expressed on natural antigen presenting cells, such as dendritic cells. Thus, B7 is not the only costimulatory molecule capable of initiating T-cell responses since a second ligand, B7-2, can provide a necessary second signal for T-cell activation.

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