scholarly journals CD169+ macrophages are sufficient for priming of CTLs with specificities left out by cross-priming dendritic cells

2015 ◽  
Vol 112 (17) ◽  
pp. 5461-5466 ◽  
Author(s):  
Caroline A. Bernhard ◽  
Christine Ried ◽  
Stefan Kochanek ◽  
Thomas Brocker

Dendritic cells (DCs) are considered the most potent antigen-presenting cells (APCs), which directly prime or cross-prime MHC I-restricted cytotoxic T cells (CTLs). However, recent evidence suggests the existence of other, as-yet unidentified APCs also able to prime T cells. To identify those APCs, we used adenoviral (rAd) vectors, which do not infect DCs but selectively accumulate in CD169+ macrophages (MPs). In mice that lack DCs, infection of CD169+ MPs was sufficient to prime CTLs specific for all epitopes tested. In contrast, CTL responses relying exclusively on cross-presenting DCs were biased to selected strong MHC I-binding peptides only. When both DCs and MPs were absent, no CTL responses could be elicited. Therefore, CD169+ MPs can be considered APCs that significantly contribute to CTL responses.

1992 ◽  
Vol 175 (1) ◽  
pp. 267-273 ◽  
Author(s):  
N Bhardwaj ◽  
S M Friedman ◽  
B C Cole ◽  
A J Nisanian

Dendritic cells are a small subset of human blood mononuclear cells that are potent stimulators of several T cell functions. Here we show they are 10-50-fold more potent than monocytes or B cells in inducing T cell responses to a panel of superantigens. Furthermore, dendritic cells can present femtomolar concentrations of superantigen to T cells even at numbers where other antigen-presenting cells (APCs) are inactive. Although dendritic cells express very high levels of the major histocompatibility complex products that are required to present superantigens, it is only necessary to pulse these APCs for 1 hour with picomolar levels of one superantigen, staphylococcal enterotoxin B, to maximally activate T cells. Our results suggest that very small amounts of superantigen will be immunogenic in vivo if presented on dendritic cells.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 196-196
Author(s):  
Nicoletta Sorvillo ◽  
Simon D van Haren ◽  
Wouter Pos ◽  
Eszter Herczenik ◽  
Rob Fijnheer ◽  
...  

Abstract Abstract 196 ADAMTS13 is a plasma metalloproteinase that regulates platelet adhesion and aggregation by virtue of its ability to process newly released ultra-large von Willebrand factor (VWF) multimers on the surface of endothelial cells. Autoantibodies directed against ADAMTS13 prohibit the processing of VWF multimers initiating a rare and life-threatening disorder called acquired thrombotic thrombocytopenic purpura (TTP). HLA-DRB1*11 has recently been identified as a risk factor for acquired TTP. This finding implies that formation of autoantibodies towards ADAMTS13 depends on appropriate presentation of ADAMTS13 derived peptides to CD4+ T-cells by antigen presenting cells. Here, we investigate endocytosis of recombinant ADAMTS13 by immature monocyte-derived dendritic cells (iDCs) using flow cytometry and confocal microscopy. Upon incubation of fluorescently labeled-rADAMTS13 with DCs, a time- and concentration dependent uptake of ADAMTS13 was observed. Endocytosis of ADAMTS13 was completely blocked upon addition of EGTA and mannan. We subsequently explored involvement of C-type lectins (CLRs) in the uptake of ADAMTS13 using specific blocking antibodies and siRNA silencing. We found that ADAMTS13 endocytosis was significantly decreased in cells treated with a monoclonal antibody directed towards macrophage mannose receptor (MR). Furthermore siRNA silencing of MR reduced the uptake of ADAMTS13 by dendritic cells. In vitro binding studies revealed that ADAMTS13 interacts with the carbohydrate recognition domains of MR. These data show that ADAMTS13 is internalized by iDCs in a MR-dependent manner. Antigen presenting cells continuously process endogenous and exogenous antigens into small peptides that are loaded on MHC class I or MHC class II for presentation to T lymphocytes. We have recently developed a method to analyze HLA-DR-presented peptide repertoires of dendritic cells pulsed with antigen (van Haren et al., 2011). Here, we addressed which ADAMTS13-derived peptides were presented on MHC class II alleles of a panel of both HLA-DRB1*11 positive and negative donors. Compared to previous studies with model antigens only a limited number of ADAMTS13-derived peptides were presented on MHC class II. Inspection of peptide-profiles obtained from DRB1*11 positive individuals revealed that two antigenic “core” peptides derived from the CUB1-2 domains of ADAMTS13 were presented by a DR11-positive donor. In addition to these immuno-dominant peptides several other peptides were also presented although with a markedly reduced efficiency. Our findings show that DRB1*11 expressing antigen presenting cells preferentially present antigenic “core” peptides derived from the CUB1-2 domains of ADAMTS13. We hypothesize that functional presentation of these peptides on HLA-DRB1*11 contributes to the onset of acquired TTP by stimulating low affinity self-reactive CD4+ T cells that have escaped negative selection in the thymus. Disclosures: No relevant conflicts of interest to declare.


2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Eytan Breman ◽  
Jurjen M. Ruben ◽  
Kees L. Franken ◽  
Mirjam H. M. Heemskerk ◽  
Dave L. Roelen ◽  
...  

In organ transplantation, alloantigens are taken up by antigen presenting cells and presented via the indirect pathway to T-cells which in turn can induce allograft rejection. Monitoring of these T-cells is of major importance; however no reliable assay is available to routinely monitor indirect allorecognition. Recently we showed that HLA monomers can be successfully used to monitor indirect allorecognition. Targeting antigens to endocytic receptors on antigen presenting cells may further enhance the presentation of antigens via HLA class II and improve the efficiency of this assay. In the current study we explored targeting of HLA monomers to either CD89 expressing monocytes or mannose receptor expressing dendritic cells. Monomer-antibody complexes were generated using biotin-labeled monomers and avidin labeling of the antibodies. We demonstrate that targeting the complexes to these receptors resulted in a dose-dependent HLA class II mediated presentation to a T-cell clone. The immune-complexes were efficiently taken up and presented to T-cells. However, the level of T-cell reactivity was similar to that when only exogenous antigen was added. We conclude that HLA-A2 monomers targeted for presentation through CD89 on monocytes or mannose receptor on dendritic cells lead to proper antigen presentation but do not enhance indirect allorecognition via HLA-DR.


Blood ◽  
2007 ◽  
Vol 110 (8) ◽  
pp. 2965-2973 ◽  
Author(s):  
Céline Beauvillain ◽  
Yves Delneste ◽  
Mari Scotet ◽  
Audrey Peres ◽  
Hugues Gascan ◽  
...  

Abstract Neutrophils are professional phagocytes that migrate early, in high number, to the infection sites. Our study has analyzed how neutrophils cross-present antigens and influence CD8+ T-cell responses. By using highly purified neutrophils from peritoneal exudates and bone marrow, we have shown that neutrophils cross-present ovalbumin to a CD8+ T-cell hybridoma and to naive CD8+ T cells from OT1 transgenic mice. Cross-presentation by neutrophils was TAP and proteasome dependent and was as efficient as in macrophages. Moreover, it actually occurred earlier than in professional antigen-presenting cells. Peritoneal exudate neutrophils from mice injected intraperitoneally with ovalbumin also cross-presented ovalbumin, proving that neutrophils take up and present exogenous antigens into major histocompatibility complex I (MHC I) molecules in vivo. We then evaluated the in vivo influence of antigen cross-presentation by neutrophils on CD8+ T-cell response using β2-microglobulin-deficient mice transferred with OT1 CD8+ T cells and injected with ovalbumin-pulsed neutrophils. Four days after neutrophil injection, OT1 cells proliferated and expressed effector functions (IFN-γ production and cytolysis). They also responded efficiently to a rechallenge with ovalbumin-pulsed dendritic cells in CFA. These data are the first demonstration that neutrophils cross-prime CD8+ T cells in vivo and suggest that they may constitute, together with professional antigen-presenting cells, an attractive target to induce cytotoxic T cells in vaccines.


2008 ◽  
Vol 87 (6) ◽  
pp. 553-557 ◽  
Author(s):  
T. Kaneko ◽  
T. Okiji ◽  
R. Kaneko ◽  
J.E. Nör ◽  
H. Suda

Substantial numbers of dendritic cells have been detected in radicular granulomas. To test the hypothesis that local antigen presentation from dendritic cells to T-cells is involved critically in immunological responses within radicular granulomas, we compared characteristics of dendritic cells and macrophages by morphological and biological analyses. Under light microscopy, HLA-DR+ and CD68+ cells showed diverse profiles, including dendritic-shaped cells. Transmission electron microscopy revealed that HLA-DR+ dendritic cells, with long cytoplasmic processes and lacking distinct phagosomes, were concentrated in the lymphocyte-rich area. HLA-DR alpha-chain, CD83, and CD86 mRNAs from HLA-DR+ dendritic cells, and CD28 mRNA from CD28+ T-cells were up-regulated in lymphocyte-rich area. Scanning electron microscopy demonstrated that the density of gold particles on dendritic cells was higher than that on HLA-DR+ macrophages. These results suggest that dendritic cells in radicular granulomas are associated with local defense reactions as stronger antigen-presenting cells, as compared with macrophages.


1995 ◽  
Vol 181 (5) ◽  
pp. 1923-1927 ◽  
Author(s):  
P Panina-Bordignon ◽  
R Lang ◽  
P M van Endert ◽  
E Benazzi ◽  
A M Felix ◽  
...  

Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease that results in the destruction of the pancreatic islet beta cells. Glutamic acid decarboxylase (GAD) has been recently indicated as a key autoantigen in the induction of IDDM in nonobese diabetic mice. In human diabetes, the mechanism by which the beta cells are destroyed is still unknown. Here we report the first evidence for the presence of GAD-specific cytotoxic T cells in asymptomatic and recent diabetic patients. GAD65 peptides displaying the human histocompatibility leukocyte antigen (HLA)-A*0201 binding motif have been synthesized. One of these peptides, GAD114-123, binds to HLA-A*0201 molecules in an HLA assembly assay. Peripheral blood mononuclear cells from individuals with preclinical IDDM, recent-onset IDDM, and from healthy controls were stimulated in vitro with the selected peptide in the presence of autologous antigen-presenting cells. In three cases (one preclinical IDDM and two recent-onset IDDM), we detected specific killing of autologous antigen-presenting cells when incubated with GAD114-123 peptide or when infected with a recombinant vaccinia virus expressing GAD65. These patients were the only three carrying the HLA-A*0201 allele among the subjects studied. Our finding suggests that GAD-specific cytotoxic T lymphocytes may play a critical role in the initial events of IDDM.


2002 ◽  
Vol 70 (9) ◽  
pp. 5167-5176 ◽  
Author(s):  
Ken Hashimoto ◽  
Yumi Maeda ◽  
Hiroaki Kimura ◽  
Koichi Suzuki ◽  
Akihiro Masuda ◽  
...  

ABSTRACT Host defense against Mycobacterium leprae infection is chiefly mediated by gamma interferon (IFN-γ)-secreting cytotoxic T cells. Since which antigen-presenting cell populations act to stimulate these T cells is not fully understood, we addressed the role of monocyte-derived dendritic cells (DCs). The DCs phagocytosed M. leprae and expressed bacterially derived antigens (Ags), such as phenolic glycolipid 1 (PGL-1), in the cytoplasm, as well as on the cell surface. The expression of HLA-ABC and -DR Ags on DCs was down-regulated by M. leprae infection, and that of CD86 was up-regulated, but not as fully as by Mycobacterium bovis BCG infection. Induction of CD83 expression required a large number of M. leprae cells. When a multiplicity of infection of >40 was used, the DCs induced a significant proliferative and IFN-γ-producing response in autologous T cells. However, these responses were significantly lower than those induced by BCG- or Mycobacterium avium-infected DCs. A CD40-mediated signaling in M. leprae-infected DCs up-regulated the expression of HLA Ags, CD86, and CD83 but did not enhance T-cell-stimulating ability. Therefore, M. leprae-infected DCs are less efficient at inducing T-cell responses. However, when the surface PGL-1 on M. leprae-infected DCs was masked by a monoclonal antibody, the DCs induced enhanced responses in both CD4+- and CD8+-T-cell subsets. M. leprae is a unique pathogen which remains resistant to DC-mediated T-cell immunity, at least in the early stages of infection.


2017 ◽  
Vol 86 (1) ◽  
Author(s):  
Laura M. Braden ◽  
Karina J. Rasmussen ◽  
Sara L. Purcell ◽  
Lauren Ellis ◽  
Amelia Mahony ◽  
...  

ABSTRACTThe histozoic myxozoan parasiteKudoa thyrsitescauses postmortem myoliquefaction and is responsible for economic losses to salmon aquaculture in the Pacific Northwest. Despite its importance, little is known about the host-parasite relationship, including the host response to infection. The present work sought to characterize the immune response in Atlantic salmon during infection, recovery, and reexposure toK. thyrsites. After exposure to infective seawater, infected and uninfected smolts were sampled three times over 4,275 degree-days. Histological analysis revealed infection severity decreased over time in exposed fish, while in controls there was no evidence of infection. Following a secondary exposure of all fish, severity of infection in the controls was similar to that measured in exposed fish at the first sampling time but was significantly reduced in reexposed fish, suggesting the acquisition of protective immunity. Using immunohistochemistry, we detected a population of MHIIβ+cells in infected muscle that followed a pattern of abundance concordant with parasite prevalence. Infiltration of these cells into infected myocytes preceded destruction of the plasmodium and dissemination of myxospores. Dual labeling indicated a majority of these cells were CD83+/MHIIβ+. Using reverse transcription-quantitative PCR, we detected significant induction of cellular effectors, including macrophage/dendritic cells (mhii/cd83/mcsf), B cells (igm/igt), and cytotoxic T cells (cd8/nkl), in the musculature of infected fish. These data support a role for cellular effectors such as antigen-presenting cells (monocyte/macrophage and dendritic cells) along with B and T cells in the acquired protective immune response of Atlantic salmon againstK. thyrsites.


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