scholarly journals A Candida albicans Mannoprotein Deprived of Its Mannan Moiety Is Efficiently Taken Up and Processed by Human Dendritic Cells and Induces T-Cell Activation without Stimulating Proinflammatory Cytokine Production

2008 ◽  
Vol 76 (9) ◽  
pp. 4359-4367 ◽  
Author(s):  
Donatella Pietrella ◽  
Patrizia Lupo ◽  
Anna Rachini ◽  
Silvia Sandini ◽  
Alessandra Ciervo ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Candida Albicans ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Vaccine Candidate ◽  
Pathogenic Fungi ◽  
T Cell Response ◽  
Necrosis Factor Alpha ◽  
Recombinant Product

ABSTRACT Mannoproteins are cell wall components of pathogenic fungi and play major virulence and immunogenic roles with both their mannan and protein moieties. The 65-kDa mannoprotein (MP65) of Candida albicans is a β-glucanase adhesin recognized as a major target of the human immune response against this fungus, and its recombinant product (rMP65; devoid of the mannan moiety) is presently under consideration as a vaccine candidate. Here we investigated cellular and molecular aspects of the interaction of rMP65 with human antigen-presenting cells. We also assessed the ability of rMP65 to initiate a T-cell response. Both the native mannosylated MP65 (nMP65) and the recombinant product were efficiently bound and taken up by macrophages and dendritic cells. However, contrarily to nMP65, rMP65 did not induce tumor necrosis factor alpha and interleukin-6 release from these cells. On the other hand, rMP65 was rapidly endocytosed by both macrophages and dendritic cells, in a process involving both clathrin-dependent and clathrin-independent mechanisms. Moreover, the RGD sequence inhibited rMP65 uptake to some extent. After internalization, rMP65 partially colocalized with lysosomal membrane-associated glycoproteins 1 and 2. This possibly resulted in efficient protein degradation and presentation to CD4+ T cells, which proliferated and produced gamma interferon. Collectively, these results demonstrate that the absence of the mannan moiety does not deprive MP65 of the capacity to initiate the pattern of cellular and molecular events leading to antigen presentation and T-cell activation, which are essential features for further consideration of MP65 as a potential vaccine candidate.

scholarly journals Acidosis-Induced TGF-β2 Production Promotes Lipid Droplet Formation in Dendritic Cells and Alters Their Potential to Support Anti-Mesothelioma T Cell Response

Cancers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1284
Author(s):  
Natalia Trempolec ◽  
Charline Degavre ◽  
Bastien Doix ◽  
Davide Brusa ◽  
Cyril Corbet ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Lipid Droplet ◽  
T Cell Activation ◽  
Cell Response ◽  
Cell Activation ◽  
Transforming Growth Factor ◽  
T Cell Response ◽  
Mesenchymal Transition

For poorly immunogenic tumors such as mesothelioma there is an imperious need to understand why antigen-presenting cells such as dendritic cells (DCs) are not prone to supporting the anticancer T cell response. The tumor microenvironment (TME) is thought to be a major contributor to this DC dysfunction. We have reported that the acidic TME component promotes lipid droplet (LD) formation together with epithelial-to-mesenchymal transition in cancer cells through autocrine transforming growth factor-β2 (TGF-β2) signaling. Since TGF-β is also a master regulator of immune tolerance, we have here examined whether acidosis can impede immunostimulatory DC activity. We have found that exposure of mesothelioma cells to acidosis promotes TGF-β2 secretion, which in turn leads to LD accumulation and profound metabolic rewiring in DCs. We have further documented how DCs exposed to the mesothelioma acidic milieu make the anticancer vaccine less efficient in vivo, with a reduced extent of both DC migratory potential and T cell activation. Interestingly, inhibition of TGF-β2 signaling and diacylglycerol O-acyltransferase (DGAT), the last enzyme involved in triglyceride synthesis, led to a significant restoration of DC activity and anticancer immune response. In conclusion, our study has identified that acidic mesothelioma milieu drives DC dysfunction and altered T cell response through pharmacologically reversible TGF-β2-dependent mechanisms.

How many dendritic cells are required to initiate a T-cell response?

Blood ◽  
2012 ◽  
Vol 120 (19) ◽  
pp. 3945-3948 ◽  
Author(s):  
Susanna Celli ◽  
Mark Day ◽  
Andreas J. Müller ◽  
Carmen Molina-Paris ◽  
Grant Lythe ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
T Cell Activation ◽  
Cell Response ◽  
Rational Design ◽  
Cell Activation ◽  
T Cell Response ◽  
Cell Responses ◽  
Precursor Frequency

Abstract T-cell activation in lymph nodes relies on encounters with antigen (Ag)–bearing dendritic cells (DCs) but the number of DCs required to initiate an immune response is unknown. Here we have used a combination of flow cytometry, 2-photon imaging, and computational modeling to quantify the probability of T cell–DC encounters. We calculated that the chance for a T cell residing 24 hours in a murine popliteal lymph nodes to interact with a DC was 8%, 58%, and 99% in the presence of 10, 100, and 1000 Ag-bearing DCs, respectively. Our results reveal the existence of a threshold in DC numbers below which T-cell responses fail to be elicited for probabilistic reasons. In mice and probably humans, we estimate that a minimum of 85 DCs are required to initiate a T-cell response when starting from precursor frequency of 10−6. Our results have implications for the rational design of DC-based vaccines.

scholarly journals Immunization with Apoptotic Phagocytes Containing Histoplasma capsulatum Activates Functional CD8+T Cells To Protect against Histoplasmosis

2011 ◽  
Vol 79 (11) ◽  
pp. 4493-4502 ◽  
Author(s):  
Shih-Hung Hsieh ◽  
Jr-Shiuan Lin ◽  
Juin-Hua Huang ◽  
Shang-Yang Wu ◽  
Ching-Liang Chu ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Response ◽  
Cell Activation ◽  
Histoplasma Capsulatum ◽  
T Cell Response ◽  
Content Type

ABSTRACTWe have previously revealed the protective role of CD8+T cells in host defense againstHistoplasma capsulatumin animals with CD4+T cell deficiency and demonstrated that sensitized CD8+T cells are restimulatedin vitroby dendritic cells that have ingested apoptotic macrophage-associatedHistoplasmaantigen. Here we show that immunization with apoptotic phagocytes containing heat-killedHistoplasmaefficiently activated functional CD8+T cells whose contribution was equal to that of CD4+T cells in protection againstHistoplasmachallenge. Inhibition of macrophage apoptosis due to inducible nitric oxide synthase (iNOS) deficiency or by caspase inhibitor treatment dampened the CD8+T cell but not the CD4+T cell response to pulmonaryHistoplasmainfection. In mice subcutaneously immunized with viableHistoplasmayeasts whose CD8+T cells are protective againstHistoplasmachallenge, there was heavy granulocyte and macrophage infiltration and the infiltrating cells became apoptotic. In mice subcutaneously immunized with carboxyfluorescein diacetate succinimidyl ester (CFSE)-labeled apoptotic macrophages containing heat-killedHistoplasma, the CFSE-labeled macrophage material was found to localize within dendritic cells in the draining lymph node. Moreover, depleting dendritic cells in immunized CD11c-DTR mice significantly reduced CD8+T cell activation. Taken together, our results revealed that phagocyte apoptosis in theHistoplasma-infected host is associated with CD8+T cell activation and that immunization with apoptotic phagocytes containing heat-killedHistoplasmaefficiently evokes a protective CD8+T cell response. These results suggest that employing apoptotic phagocytes as antigen donor cells is a viable approach for the development of efficacious vaccines to elicit strong CD8+T cell as well as CD4+T cell responses toHistoplasmainfection.

scholarly journals P04.04 Multifunctional antibody construct for in vivo targeting of dendritic cells as a therapeutic vaccination strategy in AML

2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A38.1-A38
Author(s):  
S Schmitt ◽  
A Lohner ◽  
K Deiser ◽  
A Maiser ◽  
M Rothe ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
T Cell Response ◽  
Tlr Agonists ◽  
Cross Presentation ◽  
Tnf Α

BackgroundDendritic cells (DCs) are antigen-presenting cells that induce antigen-specific T-cell responses. Therefore, they are used as tools and targets for anti-tumor vaccination. In contrast to T-cell based immunotherapies, that are often limited to surface antigens, DC-based vaccination strategies open up new therapeutic options by utilizing highly abundant intracellular tumor antigens as a target source. Among those, recent interest has been focused on the identification of neoantigens derived from tumor-specific mutations. Especially mutated Nucleophosmin 1 (ΔNPM1) is a considered candidate for targeted therapy in acute myeloid leukemia (AML). We developed a multifunctional antibody construct consisting of a peptide domain including a variable T-cell epitope that is fused to an αCD40 single chain variable fragment (scFv) with agonistic function to target and activate dendritic cells in vivo. To potentiate therapeutic efficacy, toll-like receptor (TLR) agonists can be attached as co-stimulatory domains, thereby aiming to enhance cross-presentation of conjugated (neo)antigens to CD8+ T cells.Materials and MethodsFlow cytometry and microscopy-based binding and internalization experiments were performed using monocyte-derived dendritic cells (moDCs). Upregulation of surface markers (CD80, CD83, CD86, HLA-DR) as well as cytokine secretion (IL-6 and IL-12) indicated DC maturation. To validate peptide processing and presentation, moDCs were co-cultured with autologous as well as allogeneic T cells. IFN-γ and TNF-α secretion served as a readout for T-cell activation, peptide-MHC multimer staining for T-cell proliferation.ResultsFor proof-of-principle experiments, the multispecific antibody derivative was developed by fusing the αCD40 scFv to a cytomegalovirus (CMV)-specific peptide. The αCD40.CMV construct bound CD40 agonistically and showed efficient internalization into early endosomal compartments on immature moDCs. In co-cultures of immature and mature moDCs with autologous or allogeneic T cells, αCD40.CMV induced a significantly increased T-cell activation and proliferation compared to the control. The co-administration of αCD40.CMV with various TLR agonists as vaccine adjuvants resulted in a significant upregulation of DC maturation markers in comparison to αCD40.CMV only. Interestingly, not all adjuvants were able to enhance the T-cell response. To translate this principle to the AML setting, the CMV peptide sequence was replaced with the ΔNPM1-derived and HLA-A*02:01-binding neoantigen CLAVEEVSL. Cross-presentation to CD8+ T cells transduced with a ΔNPM1-specific T-cell receptor was proven by IFN-γ and TNF-α secretion in co-cultures with moDCs that have been pre-incubated with αCD40.ΔNPM1. The optimal vaccine adjuvant has yet to be identified.ConclusionsWe successfully demonstrated the development of a multifunctional antibody construct that specifically targets and stimulates DCs by an agonistic αCD40 scFv. It simultaneously delivers a T cell-specific peptide with a vaccine adjuvant to induce an efficient T-cell response. As neoantigens are promising targets and under intense investigaton, the αCD40.ΔNPM1 fusion protein is of high therapeutic interest. Thus, our approach displays a promising DC vaccination option for the treatment of AML.Disclosure InformationS. Schmitt: None. A. Lohner: None. K. Deiser: None. A. Maiser: None. M. Rothe: None. C. Augsberger: None. A. Moosmann: None. H. Leonhardt: None. N. Fenn: None. M. Griffioen: None. K. Hopfner: None. M. Subklewe: None.

Murine Bone Marrow-Derived Dendritic Cells and T-Cell Activation by Candida albicans

2012 ◽  
pp. 261-275
Author(s):  
Joanne Gibson ◽  
Neil A. R. Gow ◽  
Simon Y. C. Wong
Keyword(s):  
Bone Marrow ◽  
Dendritic Cells ◽  
Candida Albicans ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Murine Bone Marrow

scholarly journals CD14 Expressing Precursors Give Rise to Highly Functional Conventional Dendritic Cells for Use as Dendritic Cell Vaccine

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3818
Author(s):  
Maud Plantinga ◽  
Denise A. M. H. van den Beemt ◽  
Ester Dünnebach ◽  
Stefan Nierkens
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Cord Blood ◽  
T Cell Activation ◽  
Cell Activation ◽  
Ex Vivo ◽  
Dendritic Cell Vaccine ◽  
Cell Vaccine ◽  
Activated T Cells

Induction of long-lasting immunity by dendritic cells (DCs) makes them attractive candidates for anti-tumor vaccination. Although DC vaccinations are generally considered safe, clinical responses remain inconsistent in clinical trials. This initiated studies to identify subsets of DCs with superior capabilities to induce effective and memory anti-tumor responses. The use of primary DCs has been suggested to overcome the functional limitations of ex vivo monocyte-derived DCs (moDC). The ontogeny of primary DCs has recently been revised by the introduction of DC3, which phenotypically resembles conventional (c)DC2 as well as moDC. Previously, we developed a protocol to generate cDC2s from cord blood (CB)-derived stem cells via a CD115-expressing precursor. Here, we performed index sorting and single-cell RNA-sequencing to define the heterogeneity of in vitro developed DC precursors and identified CD14+CD115+ expressing cells that develop into CD1c++DCs and the remainder cells brought about CD123+DCs, as well as assessed their potency. The maturation status and T-cell activation potential were assessed using flow cytometry. CD123+DCs were specifically prone to take up antigens but only modestly activated T-cells. In contrast, CD1c++ are highly mature and specialized in both naïve as well as antigen-experienced T-cell activation. These findings show in vitro functional diversity between cord blood stem cell-derived CD123+DC and CD1c++DCs and may advance the efficiency of DC-based vaccines.

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