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.

Regulation of Tim-3 function by binding to phosphatidylserine

2021 ◽  
Vol 478 (22) ◽  
pp. 3999-4004
Author(s):  
Lawrence P. Kane
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Transmembrane Protein ◽  
Cytotoxic T Cells ◽  
Cross Presentation ◽  
First Time

Tim-3 is a transmembrane protein that is highly expressed on subsets of chronically stimulated CD4+ helper and CD8+ cytotoxic T cells, with more transient expression during acute activation and infection. Tim-3 is also constitutively expressed by multiple types of myeloid cells. Like other TIM family members, Tim-3 can bind to phosphatidylserine displayed by apoptotic cells, and this interaction has been shown to mediate uptake of such cells by dendritic cells and cross-presentation of antigens to CD8+ T cells. In contrast, how the recognition of PS by Tim-3 might regulate the function of Tim-3+ T cells is not known. In their recent paper, Lemmon and colleagues demonstrate for the first time that recognition of PS by Tim-3 leads to enhanced T cell activation.

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.

scholarly journals Dendritic Cells Induce Peripheral T Cell Unresponsiveness under Steady State Conditions in Vivo

2001 ◽  
Vol 194 (6) ◽  
pp. 769-780 ◽  
Author(s):  
Daniel Hawiger ◽  
Kayo Inaba ◽  
Yair Dorsett ◽  
Ming Guo ◽  
Karsten Mahnke ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Steady State ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interferon Γ ◽  
Peripheral Tolerance ◽  
Antigen Delivery

Dendritic cells (DCs) have the capacity to initiate immune responses, but it has been postulated that they may also be involved in inducing peripheral tolerance. To examine the function of DCs in the steady state we devised an antigen delivery system targeting these specialized antigen presenting cells in vivo using a monoclonal antibody to a DC-restricted endocytic receptor, DEC-205. Our experiments show that this route of antigen delivery to DCs is several orders of magnitude more efficient than free peptide in complete Freund's adjuvant (CFA) in inducing T cell activation and cell division. However, T cells activated by antigen delivered to DCs are not polarized to produce T helper type 1 cytokine interferon γ and the activation response is not sustained. Within 7 d the number of antigen-specific T cells is severely reduced, and the residual T cells become unresponsive to systemic challenge with antigen in CFA. Coinjection of the DC-targeted antigen and anti-CD40 agonistic antibody changes the outcome from tolerance to prolonged T cell activation and immunity. We conclude that in the absence of additional stimuli DCs induce transient antigen-specific T cell activation followed by T cell deletion and unresponsiveness.

scholarly journals Size-transformable antigen-presenting cell–mimicking nanovesicles potentiate effective cancer immunotherapy

2020 ◽  
Vol 6 (50) ◽  
pp. eabd1631
Author(s):  
Weijing Yang ◽  
Hongzhang Deng ◽  
Shoujun Zhu ◽  
Joseph Lau ◽  
Rui Tian ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
High Surface ◽  
T Cell Response ◽  
Artificial Antigen ◽  
Antigen Presenting ◽  
Surface Redox

Artificial antigen-presenting cells (aAPCs) can stimulate CD8+ T cell activation. While nanosized aAPCs (naAPCs) have a better safety profile than microsized (maAPCs), they generally induce a weaker T cell response. Treatment with aAPCs alone is insufficient due to the lack of autologous antigen-specific CD8+ T cells. Here, we devised a nanovaccine for antigen-specific CD8+ T cell preactivation in vivo, followed by reactivation of CD8+ T cells via size-transformable naAPCs. naAPCs can be converted to maAPCs in tumor tissue when encountering preactivated CD8+ T cells with high surface redox potential. In vivo study revealed that naAPC’s combination with nanovaccine had an impressive antitumor efficacy. The methodology can also be applied to chemotherapy and photodynamic therapy. Our findings provide a generalizable approach for using size-transformable naAPCs in vivo for immunotherapy in combination with nanotechnologies that can activate CD8+ T cells.

scholarly journals Tumor Growth Enhances Cross-Presentation Leading to Limited T Cell Activation without Tolerance

2002 ◽  
Vol 195 (4) ◽  
pp. 423-435 ◽  
Author(s):  
Linh T. Nguyen ◽  
Alisha R. Elford ◽  
Kiichi Murakami ◽  
Kristine M. Garza ◽  
Stephen P. Schoenberger ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Growth ◽  
T Cell Activation ◽  
Cell Activation ◽  
Tumor Burden ◽  
High Avidity ◽  
Cross Presentation ◽  
Advanced Tumor

Using a tumor model of spontaneously arising insulinomas expressing a defined tumor-associated antigen, we investigated whether tumor growth promotes cross-presentation and tolerance of tumor-specific T cells. We found that an advanced tumor burden enhanced cross-presentation of tumor-associated antigens to high avidity tumor-specific T cells, inducing T cell proliferation and limited effector function in vivo. However, contrary to other models, tumor-specific T cells were not tolerized despite a high tumor burden. In fact, in tumor-bearing mice, persistence and responsiveness of adoptively transferred tumor-specific T cells were enhanced. Accordingly, a potent T cell–mediated antitumor response could be elicited by intravenous administration of tumor-derived peptide and agonistic anti-CD40 antibody or viral immunization and reimmunization. Thus, in this model, tumor growth promotes activation of high avidity tumor-specific T cells instead of tolerance. Therefore, the host remains responsive to T cell immunotherapy.

scholarly journals Modulation of lactate-lysosome axis in dendritic cells by clotrimazole potentiates antitumor immunity

2021 ◽  
Vol 9 (5) ◽  
pp. e002155
Author(s):  
Zining Wang ◽  
Feifei Xu ◽  
Jie Hu ◽  
Hongxia Zhang ◽  
Lei Cui ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Antigen Presentation ◽  
T Cell Activation ◽  
Therapeutic Efficacy ◽  
Antitumor Immunity ◽  
Critical Role ◽  
T Cell Response

BackgroundDendritic cells (DCs) play a critical role in antitumor immunity, but the therapeutic efficacy of DC-mediated cancer vaccine remains low, partly due to unsustainable DC function in tumor antigen presentation. Thus, identifying drugs that could enhance DC-based antitumor immunity and uncovering the underlying mechanism may provide new therapeutic options for cancer immunotherapy.MethodsIn vitro antigen presentation assay was used for DC-modulating drug screening. The function of DC and T cells was measured by flow cytometry, ELISA, or qPCR. B16, MC38, CT26 tumor models and C57BL/6, Balb/c, nude, and Batf3−/− mice were used to analyze the in vivo therapy efficacy and impact on tumor immune microenvironment by clotrimazole treatment.ResultsBy screening a group of small molecule inhibitors and the US Food and Drug Administration (FDA)-approved drugs, we identified that clotrimazole, an antifungal drug, could promote DC-mediated antigen presentation and enhance T cell response. Mechanistically, clotrimazole acted on hexokinase 2 to regulate lactate metabolic production and enhanced the lysosome pathway and Chop expression in DCs subsequently induced DC maturation and T cell activation. Importantly, in vivo clotrimazole administration induced intratumor immune infiltration and inhibited tumor growth depending on both DCs and CD8+ T cells and potentiated the antitumor efficacy of anti-PD1 antibody.ConclusionsOur findings showed that clotrimazole could trigger DC activation via the lactate-lysosome axis to promote antigen cross-presentation and could be used as a potential combination therapy approach to improving the therapeutic efficacy of anti-PD1 immunotherapy.

Bone marrow microenvironment controls the in vivo differentiation of murine dendritic cells into osteoclasts

Blood ◽  
2008 ◽  
Vol 112 (13) ◽  
pp. 5074-5083 ◽  
Author(s):  
Abdelilah Wakkach ◽  
Anna Mansour ◽  
Romain Dacquin ◽  
Emmanuel Coste ◽  
Pierre Jurdic ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Bone Cells ◽  
Activated T Cells

Abstract Finding that activated T cells control osteoclast (OCL) differentiation has revealed the importance of the interactions between immune and bone cells. Dendritic cells (DCs) are responsible for T-cell activation and share common precursors with OCLs. Here we show that DCs participate in bone resorption more directly than simply through T-cell activation. We show that, among the splenic DC subsets, the conventional DCs have the higher osteoclastogenic potential in vitro. We demonstrate that conventional DCs differentiate into functional OCLs in vivo when injected into osteopetrotic oc/oc mice defective in OCL resorptive function. Moreover, this differentiation involves the presence of activated CD4+ T cells controlling a high RANK-L expression by bone marrow stromal cells. Our results open new insights in the differentiation of OCLs and DCs and offer new basis for analyzing the relations between bone and immune systems.

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 T cells selectively filter oscillatory signals on the minutes timescale

2021 ◽  
Vol 118 (9) ◽  
pp. e2019285118
Author(s):  
Geoff P. O’Donoghue ◽  
Lukasz J. Bugaj ◽  
Warren Anderson ◽  
Kyle G. Daniels ◽  
David J. Rawlings ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Temporal Patterns ◽  
Oscillation Period ◽  
T Cell Response ◽  
Cell Activation Marker ◽  
Engineered T Cells

T cells experience complex temporal patterns of stimulus via receptor–ligand-binding interactions with surrounding cells. From these temporal patterns, T cells are able to pick out antigenic signals while establishing self-tolerance. Although features such as duration of antigen binding have been examined, our understanding of how T cells interpret signals with different frequencies or temporal stimulation patterns is relatively unexplored. We engineered T cells to respond to light as a stimulus by building an optogenetically controlled chimeric antigen receptor (optoCAR). We discovered that T cells respond to minute-scale oscillations of activation signal by stimulating optoCAR T cells with tunable pulse trains of light. Systematically scanning signal oscillation period from 1 to 150 min revealed that expression of CD69, a T cell activation marker, reached a local minimum at a period of ∼25 min (corresponding to 5 to 15 min pulse widths). A combination of inhibitors and genetic knockouts suggest that this frequency filtering mechanism lies downstream of the Erk signaling branch of the T cell response network and may involve a negative feedback loop that diminishes Erk activity. The timescale of CD69 filtering corresponds with the duration of T cell encounters with self-peptide–presenting APCs observed via intravital imaging in mice, indicating a potential functional role for temporal filtering in vivo. This study illustrates that the T cell signaling machinery is tuned to temporally filter and interpret time-variant input signals in discriminatory ways.

scholarly journals Antigen-pulsed CD8α+ Dendritic Cells Generate an Immune Response after Subcutaneous Injection without Homing to the Draining Lymph Node

1999 ◽  
Vol 189 (3) ◽  
pp. 593-598 ◽  
Author(s):  
Adrian L. Smith ◽  
Barbara Fazekas de St. Groth
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Lymph Node ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Myeloid Dendritic Cells ◽  
Draining Lymph Node

Two subsets of murine splenic dendritic cells, derived from distinct precursors, can be distinguished by surface expression of CD8α homodimers. The functions of the two subsets remain controversial, although it has been suggested that the lymphoid-derived (CD8α+) subset induces tolerance, whereas the myeloid-derived (CD8α−) subset has been shown to prime naive T cells and to generate memory responses. To study their capacity to prime or tolerize naive CD4+ T cells in vivo, purified CD8α+ or CD8α− dendritic cells were injected subcutaneously into normal mice. In contrast to CD8α− dendritic cells, the CD8α+ fraction failed to traffic to the draining lymph node and did not generate responses to intravenous peptide. However, after in vitro pulsing with peptide, strong in vivo T cell responses to purified CD8α+ dendritic cells could be detected. Such responses may have been initiated via transfer of peptide–major histocompatibility complex complexes to migratory host CD8α− dendritic cells after injection. These data suggest that correlation of T helper cell type 1 (Th1) and Th2 priming with injection of CD8α+ and CD8α− dendritic cells, respectively, may not result from direct T cell activation by lymphoid versus myeloid dendritic cells, but rather from indirect modification of the response to immunogenic CD8α− dendritic cells by CD8α+ dendritic cells.

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