Intracellular recycling and cross-presentation by MHC class I molecules

Abstract Human (h)Dectin-1 is a member of the C-type-lectin-like receptor family that was shown to be the major receptor for fungal β-glucans and to play an important role in cellular responses mediated by these carbohydrates. It is mainly expressed on human DCs and macrophages. In our study, we observed that activation of monocyte-derived dendritic cells (MDCs) with TLR3 ligand (poly I:C) but not with TLR ligand 7/8 (R848) resulted in down-regulation of hDectin-1 expression and this down-regulation correlated with a reduced uptake of apoptotic cells in phagocytosis assays. In order to analyze the possible cross-presentation of engulfed antigens we used CMV infected human fibroblasts (HFF). We found that hDectin-1 is involved in the uptake of CMV-infected HFF leading to cross-presentation of CMV-derived peptides on MHC class I molecules and activation of CMV pp65-specific CD8+ T-lymphocytes. To further delineate the pathway leading to presentation, we pretreated MDCs with compounds that inhibit processing of antigens at defined steps during presentation. Cytosolic protein degradation is performed by the proteasome, a large multicatalytic protease complex. Lactacystin specifically inhibits the 20S and 26S proteasome activity by targeting the catalytic subunit. In standard 51Cr-release assays, addition of lactacystin completely inhibited the presentation of pp65-derived peptides indicating the involvement of the proteasome in these process. The fungal product brefeldin A blocks the MHC class I processing pathway by specifically inhibiting the vesicular egress from the ER and the Golgi complex. In line with previous findings, incubation with brefeldin A almost completely abolished the lysis of MDCs incubated with CMV+ HFF. To further analyze whether the cross-presentation of CMV-derived peptides on HLA class I molecules was dependent on lysosomal proteases, MDCs that were co-incubated with HFF as above were treated with the lysosomotropic agent chloroquine that prevents acidification of the lysosomal compartment involved in the exogenous pathway of antigen presentation. The addition of chloroquine had no effect on the cross-presentation of CMV-derived epitopes on HLA class I-molecules. Summarized, the data reported here show that hDectin-1 functions not only as a pattern recognition receptor in innate immunity but is also involved in the clearing of apoptotic cells and cross-presentation of cellular antigens on MHC class I molecules to specific CTLs.

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

Journal of Experimental Medicine ◽

10.1084/jem.20020295 ◽

2002 ◽

Vol 196 (6) ◽

pp. 817-827 ◽

Cited By ~ 230

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.

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Cross-presentation of peptides from intracellular pathogens by MHC class I molecules

Annals of the New York Academy of Sciences ◽

10.1111/j.1749-6632.2009.05135.x ◽

2010 ◽

Vol 1183 (1) ◽

pp. 237-250 ◽

Cited By ~ 13

Author(s):

Nicolas Blanchard ◽

Nilabh Shastri

Keyword(s):

Mhc Class I ◽

Class I ◽

Intracellular Pathogens ◽

Cross Presentation ◽

Mhc Class I Molecules

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The comings and goings of MHC class I molecules herald a new dawn in cross-presentation

Immunological Reviews ◽

10.1111/imr.12428 ◽

2016 ◽

Vol 272 (1) ◽

pp. 65-79 ◽

Cited By ~ 39

Author(s):

J. Magarian Blander

Keyword(s):

Mhc Class I ◽

Class I ◽

Cross Presentation ◽

Mhc Class I Molecules

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The GTPase Rab3b/3c-positive recycling vesicles are involved in cross-presentation in dendritic cells

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0905684106 ◽

2009 ◽

Vol 106 (37) ◽

pp. 15801-15806 ◽

Cited By ~ 38

Author(s):

Liyun Zou ◽

Jingran Zhou ◽

Jinyu Zhang ◽

Jingyi Li ◽

Na Liu ◽

...

Keyword(s):

Dendritic Cells ◽

Mhc Class I ◽

Membrane Trafficking ◽

Molecular Mechanisms ◽

Class I ◽

Recycling Rate ◽

Rab Gtpases ◽

Cross Presentation ◽

Intracellular Membrane Transport ◽

Mhc Class I Molecules

Antigen cross-presentation in dendritic cells is a complex intracellular membrane transport process, but the underlying molecular mechanisms remain to be thoroughly investigated. In this study, we examined the effect of siRNA-mediated knockdown of 57 Rab GTPases, the key regulators of membrane trafficking, on antigen cross-presentation. Twelve Rab GTPases were identified to be associated with antigen cross-presentation, and Rab3b/3c was indicated to be colocalized with MHC class I molecules at perinuclear tubular structure. Tracing with fluorescence protein-tagged β2-microglobulin demonstrated that the MHC class I molecules were internalized from the plasma membrane to Rab3b/3c-positive compartments, which were also colocalized with the internalized transferrin. Moreover, depletion of Rab3b/3c strongly reduced the fast phase recycling rate of transferrin receptors. Furthermore, the Rab3b/3c-positive compartments were colocalized with a fraction of Rab27a at a juxtaposition of phagosomes. Together, these data demonstrate that Rab3b/3c-positive recycling vesicles are involved in and may constitute one of the recycling compartments in exogenous antigen cross-presentation.

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The many roads to cross-presentation

Journal of Experimental Medicine ◽

10.1084/jem.20051379 ◽

2005 ◽

Vol 202 (10) ◽

pp. 1313-1318 ◽

Cited By ~ 53

Author(s):

Tom A.M. Groothuis ◽

Jacques Neefjes

Keyword(s):

Endoplasmic Reticulum ◽

T Lymphocytes ◽

Mhc Class I ◽

Cytotoxic T Lymphocytes ◽

Class I ◽

Cross Presentation ◽

Peptide Loading ◽

The Many ◽

Mhc Class I Molecules

Cross-presentation of extracellular antigens by MHC class I molecules is required for priming cytotoxic T lymphocytes (CTLs) at locations remote from the site of infection. Various mechanisms have been proposed to explain cross-presentation. One such mechanism involves the fusion of the endoplasmic reticulum (ER) with the endosomal-phagosomal system, in which the machinery required for peptide loading of MHC class I molecules is introduced directly into the phagosome. Here, we discuss the evidence for and against the ER-phagosome concept as well as other possible mechanisms of cross-presentation.

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IFN-g-Stimulated Mesenchymal Stromal Cells Acquire the Ability To Cross-Present Exogenous Soluble Antigens and Lead to an Effective Immune Response.

Blood ◽

10.1182/blood.v110.11.4898.4898 ◽

2007 ◽

Vol 110 (11) ◽

pp. 4898-4898

Author(s):

Moïra François ◽

Raphaëlle Romieu-Mourez ◽

Sophie Stock-Martineau ◽

Jacques Galipeau

Keyword(s):

Immune Response ◽

Antigen Presentation ◽

Mhc Class I ◽

Mesenchymal Stromal Cells ◽

Stromal Cells ◽

Class I ◽

Hybridoma Cells ◽

Cross Presentation ◽

Mhc Class I Molecules

Abstract Antigen cross-presentation is the mechanism by which exogenous antigens can be presented by major histocompatibility complex (MHC) class I molecules to CD8+ T cells. This process is efficiently performed by professional antigen presenting cells (APC) such as dendritic cells and macrophages. Recently, we and others have shown that IFN-g enables the upregulation of the expression of MHC class I & II molecules by marrow-derived Mesenchymal Stromal Cells (MSCs) and that MHC II-mediated antigen presentation can lead to cell-mediated protective immunity to xenoantigens [Stagg et al., Blood March 2006]. These findings led us to investigate whether MSCs also possess the ability to cross-present antigens via MHC class I. Using antigen presentation assays performed on murine MSC in the presence of MHC class I-restricted ovalbumin (OVA)-specific CD8+ T hybridoma cells or purified primary CD8+ T lymphocytes from OT1 transgenic mice, we demonstrated that MSC can robustly and effectively cross-present exogenous antigens via MHC class I molecules upon IFN-g pre-treatment in a manner comparable to professional APCs like macrophages. Use of transporter associated with antigen processing (TAP-1)-deficient mice and proteasome inhibitors suggested a MHC class I machinery-dependent pathway. Cross-presentation by IFN-g-activated MSC was also observed to be suppressed by TGF-b and regulated by cell density. In vivo, IFN-g-treated, OVA-pulsed MSCs administered to normal C57Bl/6 mice led to an effective OVA-specific, T cell cytotoxic immune response, leading to the rejection of OVA-expressing EG7 lymphoma cells. In conclusion, our findings suggest that cross-presentation properties of MSC could play a role in their effectiveness as conditional APCs in vivo and this property may be exploited as a therapeutic cell-based immune biopharmaceutical for treatment of cancer or infectious disease.

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