scholarly journals Lipocalin 2 regulates expression of MHC class I molecules in Mycobacterium tuberculosis-infected dendritic cells via ROS production

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ji-Ae Choi ◽  
Soo-Na Cho ◽  
Junghwan Lee ◽  
Sang-Hun Son ◽  
Doan Tam Nguyen ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Proliferation ◽  
Dendritic Cells ◽  
Mycobacterium Tuberculosis ◽  
Mhc Class I ◽  
Class I ◽  
T Cell Proliferation ◽  
Oxygen Species ◽  
Lipocalin 2 ◽  
Mhc Class I Molecules

Abstract Background Iron has important roles as an essential nutrient for all life forms and as an effector of the host defense mechanism against pathogenic infection. Lipocalin 2 (LCN2), an innate immune protein, plays a crucial role in iron transport and inflammation. In the present study, we examined the role of LCN2 in immune cells during Mycobacterium tuberculosis (Mtb) infection. Results We found that infection with Mtb H37Ra induced LCN2 production in bone marrow-derived dendritic cells (BMDCs). Notably, expression of MHC class I molecules was significantly reduced in LCN2−/− BMDCs during Mtb infection. The reduced expression of MHC class I molecules was associated with the formation of a peptide loading complex through LCN2-mediated reactive oxygen species production. The reduced expression of MHC class I molecules affected CD8+ T-cell proliferation in LCN2−/− mice infected with Mtb. The difference in the population of CD8+ effector T cells might affect the survival of intracellular Mtb. We also found a reduction of the inflammation response, including serum inflammatory cytokines and lung inflammation in LCN2−/− mice, compared with wild-type mice, during Mtb infection. Conclusions These data suggest that LCN2-mediated reactive oxygen species affects expression of MHC class I molecules in BMDCs, leading to lower levels of CD8+ effector T-cell proliferation during mycobacterial infection.

scholarly journals Long-Peptide Cross-Presentation by Human Dendritic Cells Occurs in Vacuoles by Peptide Exchange on Nascent MHC Class I Molecules

2016 ◽  
Vol 196 (4) ◽  
pp. 1711-1720 ◽  
Author(s):  
Wenbin Ma ◽  
Yi Zhang ◽  
Nathalie Vigneron ◽  
Vincent Stroobant ◽  
Kris Thielemans ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Mhc Class I ◽  
Class I ◽  
Cross Presentation ◽  
Peptide Exchange ◽  
Human Dendritic Cells ◽  
Mhc Class I Molecules

scholarly journals Constitutive versus Activation-dependent Cross-Presentation of Immune Complexes by CD8+ and CD8− Dendritic Cells In Vivo

2002 ◽  
Vol 196 (6) ◽  
pp. 817-827 ◽  
Author(s):  
Joke M.M. den Haan ◽  
Michael J. Bevan
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Mhc Class I ◽  
Cd8 T Cells ◽  
Immune Complexes ◽  
Class I ◽  
Cross Presentation ◽  
Deficient Mice ◽  
Mhc Class I Molecules

Murine splenic dendritic cells (DCs) can be divided into two subsets based on CD8α expression, but the specific role of each subset in stimulation of T cells is largely unknown. An important function of DCs is the ability to take up exogenous antigens and cross-present them in the context of major histocompatibility complex (MHC) class I molecules to CD8+ T cells. We previously demonstrated that, when cell-associated ovalbumin (OVA) is injected into mice, only the CD8+ DC subset cross-presents OVA in the context of MHC class I. In contrast to this selectivity with cell-associated antigen, we show here that both DC subsets isolated from mice injected with OVA/anti-OVA immune complexes (OVA-IC) cross-present OVA to CD8+ T cells. The use of immunoglobulin G Fc receptor (FcγR) common γ-chain–deficient mice revealed that the cross-presentation by CD8− DCs depended on the expression of γ-chain–containing activating FcγRs, whereas cross-presentation by CD8+ DCs was not reduced in γ-chain–deficient mice. These results suggest that although CD8+ DCs constitutively cross-present exogenous antigens in the context of MHC class I molecules, CD8− DCs only do so after activation, such as via ligation of FcγRs. Cross-presentation of immune complexes may play an important role in autoimmune diseases and the therapeutic effect of antitumor antibodies.

scholarly journals Presentation of Exogenous Protein Antigens on Major Histocompatability Complex Class I Molecules by Dendritic Cells: Pathway of Presentation and Regulation by Cytokines

Blood ◽  
1997 ◽  
Vol 90 (4) ◽  
pp. 1594-1599 ◽  
Author(s):  
Peter Brossart ◽  
Michael J. Bevan
Keyword(s):  
Dendritic Cells ◽  
Mhc Class I ◽  
Class I ◽  
Cell Surface Expression ◽  
Major Histocompatability Complex ◽  
Peptide Epitopes ◽  
Proinflammatory Mediators ◽  
Tnf Α ◽  
Ifn Γ ◽  
Mhc Class I Molecules

Abstract Several recent studies have shown that dendritic cells (DC) pulsed with soluble proteins can present peptide epitopes derived from these exogenous antigens on major histocompatability complex (MHC) class I molecules and induce an antigen-specific cytotoxic T lymphocyte (CTL) response. We provide evidence here that DC use macropinocytosis to capture soluble antigens that are then presented on MHC class I molecules. The presentation of an epitope derived from soluble ovalbumin was transporter associated with antigen presentation (TAP)-dependent, brefeldin A-sensitive, blocked by inhibitors of proteasomes, and resistant to chloroquine. These data suggest that exogenous antigens access the cytosol of DC and are proccessed for presentation via the same pathway described for conventional MHC class I-restricted cytosolic antigens. Proinflammatory mediators such as tumor necrosis factor-α (TNF-α) and lipopolysaccharide (LPS) reduced the efficiency of ovalbumin presentation via this pathway. This reduced presentation was not due to impaired expression of class I molecules because these substances upregulated the cell surface expression of Kb-molecules comparable to levels induced by interferon-γ (IFN-γ) treatment. The addition of IFN-γ increased ovalbumin presentation even in the presence of TNF-α or LPS. These results show that DC might be involved in the cross-priming phenomenon. This could offer the immune system an additional pathway for effective priming of cytotoxic T cells and provide the possibility to activate both CD4 and CD8 T-cell responses.

Identification of a Two-Step Mechanism Responsible for Antibody-Mediated Transfusion Related Acute Lung Injury (TRALI)

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 846-846
Author(s):  
Christopher G.J. McKenzie ◽  
Michael Kim ◽  
Tarandeep Singh ◽  
John W. Semple
Keyword(s):  
Reactive Oxygen Species ◽  
Acute Lung Injury ◽  
Lung Injury ◽  
Mhc Class I ◽  
Reactive Oxygen ◽  
Lung Damage ◽  
Class I ◽  
Oxygen Species ◽  
Neutrophil Accumulation

Abstract Abstract 846 Transfusion-related acute lung injury (TRALI) is one of the leading causes of transfusion fatalities, and most TRALI reactions are thought to be caused by donor antibodies. It is currently thought that the donor antibodies activate pulmonary neutrophils to produce reactive oxygen species that damage lung tissue. There have been several animal models of TRALI developed including, for example, ex vivo lung models demonstrating the importance of human anti-neutrophil antibodies in TRALI, and in vivo models showing how biological response modifiers can induce recipient lung damage. An in vivo murine model of antibody-mediated TRALI was developed in 2006, and has also shown several similarities with human TRALI induction (Looney MR et al., J Clin Invest 116: 1615, 2006). Specifically, a monoclonal anti-mouse MHC class I antibody (34-1-2s) causes significant increases in excess lung water, lung vascular permeability and mortality within 2 hours after administration. These adverse reactions were found to be due to the antibody's ability to activate pulmonary neutrophils to produce reactive oxygen species (ROS) in an Fc receptor (FcR)-dependent manner. In contrast, however, it was recently shown that 34-1-2s induces pulmonary damage by activating macrophages to generate ROS in a complement (C5a)-dependent process (Strait RT J et al., Exp Med 208: 2525, 2011). In order to better understand this apparent controversy, we attempted to determine the nature of how 34-1-2s mediates its lung damaging properties. 34-1-2s was digested with pepsin or papain to produce F(ab')2 or Fc fragments respectively, and the fragments were tested for their ability to mediate TRALI reactions. In control mice, when intact 34-1-2s antibody was intravenously injected into either CB.17 mice with severe combined immunodeficiency or C5 deficient DBA/2 mice, increased shock, serum MIP-2 (murine equivalent to human IL-8) levels, pulmonary neutrophil accumulation, pulmonary edema and mortality all occurred within 2 hours. In contrast, however, injection with 34-1-2s F(ab')2 fragments was only able to generate MIP-2 production and pulmonary neutrophil accumulation; no lung damage or mortality occurred. Injection of 34-1-2s Fc fragments either alone or together with equal molar concentrations of F(ab')2 fragments failed to induce any lung damage or mortality. These results suggest that 34-1-2s recognition of it's cognate MHC class I antigen may be a priming reaction that stimulates MIP-2 and chemotaxis of neutrophils to the lungs, whereas the Fc portion of the intact molecule is responsible for the second step of exacerbating TRALI symptoms in a complement independent manner. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Cd8+ but Not Cd8− Dendritic Cells Cross-Prime Cytotoxic T Cells in Vivo

2000 ◽  
Vol 192 (12) ◽  
pp. 1685-1696 ◽  
Author(s):  
Joke M.M. den Haan ◽  
Sophie M. Lehar ◽  
Michael J. Bevan
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Mhc Class I ◽  
Cytotoxic T Lymphocyte ◽  
Cytotoxic T Cells ◽  
Class I ◽  
Specific Subset ◽  
Mhc Class I Molecules

Bone marrow–derived antigen-presenting cells (APCs) take up cell-associated antigens and present them in the context of major histocompatibility complex (MHC) class I molecules to CD8+ T cells in a process referred to as cross-priming. Cross-priming is essential for the induction of CD8+ T cell responses directed towards antigens not expressed in professional APCs. Although in vitro experiments have shown that dendritic cells (DCs) and macrophages are capable of presenting exogenous antigens in association with MHC class I, the cross-presenting cell in vivo has not been identified. We have isolated splenic DCs after in vivo priming with ovalbumin-loaded β2-microglobulin–deficient splenocytes and show that they indeed present cell-associated antigens in the context of MHC class I molecules. This process is transporter associated with antigen presentation (TAP) dependent, suggesting an endosome to cytosol transport. To determine whether a specific subset of splenic DCs is involved in this cross-presentation, we negatively and positively selected for CD8− and CD8+ DCs. Only the CD8+, and not the CD8−, DC subset demonstrates cross-priming ability. FACS® studies after injection of splenocytes loaded with fluorescent beads showed that 1 and 0.6% of the CD8+ and the CD8− DC subsets, respectively, had one or more associated beads. These results indicate that CD8+ DCs play an important role in the generation of cytotoxic T lymphocyte responses specific for cell-associated antigens.

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