scholarly journals 605 Systemically administered HER2-targeted ISACs provoke a rapid, local response that engages the innate and adaptive arms of the immune system to eradicate tumors in preclinical models

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A640-A640
Author(s):  
Heidi LeBlanc ◽  
Cecelia Pearson ◽  
Justin Kenkel ◽  
LIsa Blum ◽  
Po Ho ◽  
...  
Keyword(s):  
T Cells ◽  
Immune System ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Single Agent ◽  
Fold Increase ◽  
List Type ◽  
Dependent Manner ◽  
Activation Markers

BackgroundImmune-stimulating antibody conjugates (ISACs) covalently attach immune stimulants to tumor-targeting antibodies such as trastuzumab. We have shown that HER2-targeted TLR7/8 ISACs elicit robust myeloid activation and tumor eradication in a TLR- and Fc-dependent manner in trastuzumab-resistant and HER2-low models. Upon treatment with ISACs, T cell-mediated immunological memory extends to tumor antigens beyond HER2.1 Here we describe the ISAC mechanism of action in vivo that leads to eradication of tumors in mice.MethodsEstablished syngeneic rHER2- or xenograft HER2-expressing tumors treated with anti-HER2 ISACs or appropriate controls were assessed for gene expression by NanoString Pan-Cancer Immune Profiling panel comprising 750 genes related to tumor immune biology. Tumor cytokines were measured using MesoScale Discovery (MSD) technology, and immune cell infiltrates were assessed by immunohistochemistry (IHC). Anti-tumor efficacy was assessed after depletion of CD8+ T cells and phagocytes.ResultsWithin 24 hours of administration, HER2-directed ISACs induced robust, target-dependent activation of the immune system. In a syngeneic tumor model, 34% of the measurable genes were significantly upregulated after treatment with the rHER2-targeted ISAC vs 0.1% with the non-binding ISAC control. Similarly, 13% vs 0% of genes were upregulated in a xenograft model after HER2-targeted vs control ISAC treatment. In both models anti-HER2 ISAC treatment led to activation of pathways indicative of TLR7/8 agonism (e.g. IRF-7; type 1 interferons), and FcgR engagement (e.g. NF-kappaB associated genes). Cytokines and chemokines, including myeloid chemokines CCL2/3/4 and T cell chemokines CXCL9/10/11 were specifically upregulated in the tumors at the gene and protein level, indicating robust activation of myeloid cells following anti-HER2 ISAC treatment. Furthermore, in syngeneic tumors T cell activation markers (e.g. Granzyme B; IFN-gamma) were induced within 24 hours post treatment with an anti-rHER2 ISAC, and IHC at day 6 showed a 5-fold increase in CD11c+ cells. Control-treated tumors had sparse CD8+ T cells, whereas rHER2-targeted ISAC treatment led to ~3.5-fold increase in T cell frequency that shifted the tumor microenvironment from immunologically cold to hot. The recruitment of both phagocytes and CD8+ T cells was consequential, as depletion of either abrogated anti-tumor efficacy of the rHER2-targeted ISAC. Systemically delivered ISACs were well-tolerated.ConclusionsIn contrast to other immune therapies, such as anti-PDL1/PD1 and anti-CD40, systemically administered ISACs locally engage both the innate and adaptive arms of the immune system to eradicate tumors. The molecular and cellular phenotype associated with ISAC-mediated activation is being evaluated in the on-going BDC-1001 Phase I/II clinical trial.2ReferenceAckerman Set al, Poster# P756, SITC 20192. Phase 1/2 Study of BDC-1001 as a Single Agent and in Combination With Pembrolizumab in Patients With Advanced HER2-Expressing Solid Tumors; ClinicalTrials.gov (NCT04278144)

Molecular Transfer of Human CD40 and OX40 Ligands to Leukemic Human B-CLL Cells Extensively Expands Tumor-Reactive Cytotoxic T-Lymphocytes.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 951-951
Author(s):  
Ettore Biagi ◽  
Giampietro Dotti ◽  
Eric Yvon ◽  
Raphael Rousseau ◽  
Edward Lee ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Fold Increase ◽  
Mean Value ◽  
Lymphocytic Leukemia ◽  
Molecular Transfer

Abstract CD40 ligand is an accessory signal for T-cell activation and can overcome T-cell anergy. The OX40-OX40 ligand pathway is involved in the subsequent expansion of memory T cells. We expressed both human CD40L and OX40L on B-Chronic Lymphocytic Leukemia (B-CLL) cells, by exploiting the phenomenon of molecular transfer from fibroblasts engineered to over-express both of these TNF-receptor superfamily members. We analyzed the effects of the modified B-CLL cells on the number, phenotype and cytotoxic function of autologous T cells in seven B-CLL patients. Transfer of CD40L and OX40L to B-CLL cells was observed in all patients (mean value from 1% pre to 76% post for CD40L; from 0.7% pre to 88% post for OX40L). Subsequent up-regulation of the costimulatory molecules CD80 (B7-1) and CD86 (B7-2) was obtained after engagement of the endogenous CD40 receptor on B-CLL by the transferred CD40L molecules (mean value from 8% pre to 64% post for CD80; from 36% pre to 95% post for CD86). Co-culture of modified and unmodified B-CLL cells with autologous T cells revealed profound differences in the immune responses they induced. With unmodified B-CLL cells, or cells expressing either CD40L or OX40L individually, less than a 10-fold expansion of autologous T cells was observed, with a <100-fold expansion in tumor reactive T cells (measured by IFN-gamma Elispot with autologous B-CLL cells as stimulators, and allogeneic B-CLL cells as controls). By contrast, co-culture with B-CLL cells expressing both CD40L and OX40L induced a >40 fold expansion of autologous T cells - including both CD8+ T cells and CD4+ T cells with a Th1 pattern of cytokine release - and a >2500-fold increase in leukemia-reactive T cells. These expanded T cells were also directly cytotoxic to B-CLL targets, producing a mean 48% B-CLL killing at an E:T ratio of 10:1. A proportion of these tumor-reactive CD8+ T cells were specific for survivin, a B-CLL associated tumor antigen. Hence the combination of CD40L and OX40L expression by B-CLL cells allows generation of potent immune responses to B-CLL, which may be exploitable either by using active immunization with CD40L/OX40L-modified tumor cells or by adoptive immunotherapy with CD40L/OX40L generated tumor-reactive T cells.

scholarly journals 699 A differentiated anti-OX40 agonist BGB-A445 does not block OX40-OX40L interaction and reveals remarkable anti-tumor efficacy in preclinical models

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A741-A741
Author(s):  
Ye Liu ◽  
Beibei Jiang ◽  
Tong Zhang ◽  
Zuobai Wang ◽  
Yingcai Feng ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Colon Cancer ◽  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Single Agent ◽  
List Type ◽  
Dependent Manner ◽  
Agonistic Antibody

BackgroundOX40 is a member of the tumor necrosis factor receptor super family (TNFRSF) primarily expressed on activated CD4+ and CD8+ T cells, as well as natural killer (NK) T and NK cells. It is an immune costimulatory receptor which binds to its ligand OX40L and activates downstream NF-κB pathway to induce immune cell activation, proliferation, and survival.1–3 Current agonistic anti-OX40 antibodies in clinic, which are mostly ligand-competitive antibodies, showed limited clinical responses, mainly at lower doses. Blockade of OX40-OX40L interaction might limit the efficacy of these ligand-competitive antibodies at higher doses, as OX40-OX40L interaction is essential for enhancing effective anti-tumor immunity. Here we report pre-clinical data of BGB-A445, which is a ligand non-blocking agonistic anti-OX40 humanized antibody.MethodsCell-based flow cytometry assay was established to determine whether BGB-A445 interferes with OX40-OX40L interaction. Co-crystal structure of OX40/BGB-A445 Fab was solved to study the molecular binding mechanism. A mixed lymphocyte reaction (MLR) assay was set up to investigate the ability of BGB-A445 to activate CD4+ T-cells. The anti-tumor efficacy of BGB-A445 was evaluated in MC38 colon cancer and CT26WT colon cancer models either as a single agent or in combination with anti-PD-1 antibody.ResultsThe flow cytometry study showed that BGB-A445 did not interfere with the binding of OX40 to OX40L even at high concentrations. In contrast, MOXR0916, an anti-OX40 agonistic antibody developed by Genentech, completely blocked OX40 binding to OX40L. Additionally, the co-crystal structure of OX40/BGB-A445 Fab complex indicated that BGB-A445 interacts with the CRD4 region of OX40 which is distant from OX40L binding region. In the MLR assay, combined with an anti-PD-1 antibody, BGB-A445 co-stimulated CD4+ T-cells to secrete IL-2 dose-dependently, while MOXR0916 did not. In the MC38 colon cancer model in human OX40 knock-in mice, BGB-A445 demonstrated remarkable anti-tumor efficacy in a dose-dependent manner, while MOXR0916 showed a ‘hook effect’ in the same setting. In addition, BGB-A445 exhibited significant anti-tumor activity in the PAN02 pancreatic model which is resistant to anti-PD-1 treatment. Besides, BGB-A445 revealed significant combination effects with anti-PD-1 therapy in both MC38 and CT26WT models.ConclusionsIn conclusion, differentiated from current clinical stage anti-OX40 antibodies, BGB-A445 is an agonistic antibody that does not block the OX40-OX40L interaction. Both in vitro and in vivo results demonstrated that BGB-A445 has remarkable immune stimulating effect and anti-tumor efficacy either as a single agent or in combination with anti-PD-1 therapy, thus warranting further clinical investigation.ReferencesCroft M. Control of immunity by the TNFR-related molecule OX40 (CD134). Annu Rev Immunol 2010;28:57–78.Gramaglia I, et al. Ox-40 ligand: a potent costimulatory molecule for sustaining primary CD4 T cell responses. J Immunol 1998;161:6510–6517.Song J, So T, Croft M. Activation of NF-kappaB1 by OX40 contributes to antigen-driven T cell expansion and survival. J Immunol 2008;180:7240–7248.

Immune Dysfunction in Patients with MDS Is Partially Corrected in EPO-Treated Patients: Differences According to WHO Classification

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3165-3165
Author(s):  
Howard S Oster ◽  
Naamit Deshet-Unger ◽  
Drorit Neumann ◽  
Moshe Mittelman ◽  
Nir Maaravi ◽  
...  
Keyword(s):  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Cd8 T Cells ◽  
Healthy Subjects ◽  
Advanced Disease ◽  
Fold Increase ◽  
Refractory Anemia ◽  
Cd8 Cells ◽  
Cell Numbers

Abstract Background: The immune system has been shown to be involved in the pathogenesis of myelodysplastic syndromes (MDS), and is also affected by the disease. Recombinant erythropoietin (rHuEPO), or in general, erythroid stimulating agents (ESAs) have become a standard treatment for anemic patients with MDS. They were found to improve anemia, quality of life, and possibly survival. We have previously demonstrated that EPO has effects on cellular and humoral immunity and specifically, on immune function in patients with multiple myeloma (MM). Here we report our findings demonstrating the effect of ESAs on T cell (CD4+, CD8+ and CD4+CD25+) number and function in patients with MDS. Patients and Methods: We examined three groups: healthy subjects ('Control', 20 participants), MDS patients without ESA treatment ('MDS', 13), and MDS patients treated with an ESA ('MDS+EPO', 17). All diagnosed patients gave informed consent as approved by our IRB. Cell numbers were evaluated with flow cytometry. In a subset of patients, cell activation was assessed in response to phytohemagglutinin (PHA) by examining CD69 expression in both CD4+ and CD8+ cells. The co-stimulatory marker, CD28, and the inhibitory marker CTLA-4 (CD152) were evaluated as well. We also examined World Health Organization (WHO) subgroups, refractory anemia (RA) and RA with ringed sideroblasts (RARS) versus more advanced disease. Results: CD4+ and CD8+ T cell levels are reduced and increased respectively in MDS patients compared to control, and these changes are reversed in MDS+EPO (Table 1, CD4+, p<0.01; CD8+, p=0.05). The CD4+:CD8+ ratio (Table 1) is reduced and nearly equalized in MDS (1.16), but approaches that of the control (2.24) in MDS+EPO (1.94). CD4+CD25+ T cell numbers (including regulatory T cells), were lower in MDS patients and improve in the MDS+EPO group (Table 1). In vitro activation of T cells (CD4+CD69+ and CD8+CD69+) achieves an approximately 15-fold increase in healthy subjects. MDS patients without EPO sustained only a 7.17 fold increase in CD4+ activation versus 13.64 fold for the MDS+EPO group (p<0.01); for CD8+ T cells, 10.20 fold (MDS) versus 18.56 fold (MDS+EPO, p<0.01). The expression of the co-stimulatory marker CD28 was decreased in both CD4+ and CD8+ T cells in MDS, and approached normal in MDS+EPO in CD4+ T cells (Table 1). There was no significant change in inhibitory CTLA-4 (CD152) expression among the groups (not shown). Subgroup analysis demonstrated that ESA has a similar effect on CD4+ and CD8+ cells and their ratio in both RA/RARS and more advanced disease, similar to those of the whole cohort (Table 2, green). On the other hand, some parameters were affected by ESA only in one subgroup (Table 2, blue): The ESA effect on CD4+CD25+ cells was evident only in patients with advanced disease (Table 2, blue). ESA affected CD4+ and CD8+ cell stimulation (CD69) in RA/RARS, similar to that seen in the whole cohort (Table 2, blue). Of note, in more advanced disease, CD4+ and CD8+ cells achieved stimulation in the MDS group not treated with ESA, with no difference between MDS and MDS+EPO. This finding needs to be further addressed in larger cohorts and with additional markers of activation. Conclusions: MDS patients display T-cell abnormalities that are improved upon EPO treatment. MDS is a heterogeneous disease where the immune system both affects and is affected by the disease. As such, treatment with ESAs might ameliorate not only the anemia, but also the immune deficiencies and perhaps the disease itself. Future studies will clarify the immunomodulatory role of ESA in the various stages of MDS. Disclosures No relevant conflicts of interest to declare.

Phase 1b study with PEGylated human IL-10 (AM0010) with 5-FU and oxaliplatin (FOLFOX) in metastatic pancreatic adenocarcinoma (PDAC).

2017 ◽  
Vol 35 (4_suppl) ◽  
pp. 399-399 ◽  
Author(s):  
J. Randolph Hecht ◽  
Aung Naing ◽  
Gerald Falchook ◽  
Manish R. Patel ◽  
Jeffrey R. Infante ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
De Novo ◽  
Single Agent ◽  
Hematological Toxicity ◽  
Phase 1B

399 Background: The benefit of adding nal-irinotecan or oxaliplatin to 5-FU in second-line therapy for PDAC is relatively small and it has been refractory to immune therapies. The success and the durability of immunotherapy is thought to depend on the activation and expansion of intratumoral, tumor specific cytotoxic CD8+ T cells which are absent in most PDACs. AM0010 stimulates the survival, expansion and cytotoxicity of intratumoral CD8+ T cells. Immune stimulation and prolonged stable disease in PDAC patients (pts) with single agent AM0010 was recently presented. Irinotecan may eliminate cytotoxic T cells. Treatment with platinum or 5-FU may activate immune responses to cancer and AM0010 has synergistic anti-tumor function with both in preclinical models. In this phase 1b clinical study, the efficacy of AM0010 with FOLFOX was explored in patients with PDAC. Methods: PDAC pts progressing on a median of 1 prior therapy (range 1-3) were treated daily with AM0010 in combination with FOLFOX (n=20). Tumor responses were monitored using irRC. Immune responses were monitored using analysis of serum cytokines, activation of blood derived T cells and peripheral T cell clonality. Pretreatment samples were analyzed by IHC for tumor infiltration by CD8+ T cells. Results: G3/4 TrAEs included thrombocytopenia (55%), anemia (45%) and neutropenia (25%). There was no significant bleeding or febrile neutropenia. 16 pts had a objective tumor response assessment; 2 had an irCR, 1 an irPR, 10 had irSD. Eight remain on treatment, 2 for > 1 year. ORR was 15%, the DCR was 65%. The mPFS was 3.9 months. AM0010 increased serum Th1 cytokines and reduced mediators of chronic inflammation IL-23 and IL-17 and the immunosuppressive cytokine TGFb. AM0010 increased the number and proliferation of PD1+ activated CD8+ T cells and induced de-novo oligoclonal expansion of T cell clones without affecting total lymphocyte counts. Conclusions: AM0010 with FOLFOX is well tolerated with moderate hematological toxicity in patients with PDAC. The observed immune activation including CD8+ T cell activation and prolonged objective responses are encouraging and will be explored in a phase 3 trial starting in 2016.

370 Pharmacodynamic assessment of a novel FAP-targeted 4–1BB agonist, administered as single agent and in combination with atezolizumab to patients with advanced solid tumors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A395-A395
Author(s):  
Victor Moreno ◽  
Tatiana Hernandez ◽  
Ignacio Melero ◽  
Miguel Sanmamed ◽  
Iben Spanggaard ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Solid Tumors ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Dose Range ◽  
Single Agent ◽  
Ifn Gamma

BackgroundRO7122290 (RO) is a bispecific antibody-like fusion protein that simultaneously targets FAP, abundantly expressed by cancer-associated fibroblasts in most solid tumors, and 4-1BB, transiently expressed on activated T cells. Pre-clinical experiments revealed strong intra-tumoral CD8+ T cells infiltration in FAP-positive tumors, cytokines induction and significant anti-tumor activity mediated by RO (signal 2 of T cell activation), upon TCR/CD3 engagement (signal 1) or in combination with atezolizumab (ATZ). In this first-in-human study, the pharmacodynamic (PD) effects of RO were assessed, both as single agent (SA) (Part A) and in combination with ATZ (Part B).MethodsPts with advanced and/or metastatic solid tumors were eligible for this ongoing Phase 1/1b trial (EUDRACT 2017-003961-83). RO was administered intravenously, weekly (QW) at escalating dose levels (DLs). In Part A, 62 pts were treated at 13 DLs of RO, dose range 5–2000 mg. In Part B, 39 pts were treated at 8 DLs of RO, dose range 45–2000 mg, with ATZ 1200 mg Q3W. Secondary biomarker objective was characterization of PD effects in tumor tissue and blood. The endpoints were change from baseline in intra-tumoral density (cell/mm2) and proliferation (Ki67) of CD8+ T cells measured by immunohistochemistry (IHC), and change in activation (4-1BB) and proliferation (Ki67) of peripheral CD8+ T cells measured by flow cytometry. Exploratory objectives were characterization of PD effects in plasma/serum and measurement of intra-tumoral immune activation. The endpoints were change in peripheral cytokines (TNF-alfa, IFN-gamma, IL-6) and soluble(s) factors (sCD25, s4-1BB) concentration measured by ELISA, and intra-tumoral changes in gene expression measured by RNAseq.ResultsIn the periphery, we observed transient expression of 4-1BB on CD4+ and CD8+ T cells, along with secretion of s4-1BB and inflammatory cytokines, suggesting 4-1BB targeting and potent T cell activation. The concomitant induction of proliferating T cells indicated the potential association to priming and formation of tumor-reactive T cells. In the tumor, we detected increased CD8+ T cells infiltration and proliferation, in both Parts. Proliferating CD8+ T cells increased in both tumor nests and surrounding stroma, with a preferential accumulation in the latter. RNAseq analysis revealed induction of 4-1BB, PD-1 and IFN-gamma, indicating intra-tumoral T cells activation in Part B.ConclusionsPD activity was consistent with the postulated MoA, confirming RO to be a potent tumor-targeted 4-1BB agonist in the clinical setting. Our observations suggest that RO can synergize with endogenous T cell receptor stimulation, both as SA and in combination with ATZ.

scholarly journals Lactate potentiates differentiation and expansion of cytotoxic T cells

2019 ◽  
Author(s):  
Helene Rundqvist ◽  
Pedro Veliça ◽  
Laura Barbieri ◽  
Paulo A. Gameiro ◽  
Pedro P. Cunha ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cancer Progression ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Tumour Growth ◽  
Tumour Progression ◽  
Cytotoxic T Cells ◽  
Malignant Tumour ◽  
Dependent Manner

AbstractExercise has a range of effects on metabolism. In animal models, repeated exertion reduces malignant tumour progression, and clinically, exercise can improve outcome for cancer patients. The etiology of the effect of exercise on tumour progression is unclear, as are the cellular actors involved. We show here that exercise-induced reduction in tumour growth is dependent on CD8+ T cells and that lactate, which is produced at high levels during exertion, increases proliferative capacity and cytotoxicity of CD8+ T cells. We found that at elevated levels lactate is used as a fuel during T cell activation. We further found that injection of lactate into animals can reduce malignant tumour growth in a dose-and CD8+ T cell-dependent manner. These data demonstrate that lactate can act to increase the anti-tumour activity of cytotoxic T cells, and in so doing, reduce cancer progression.

Immune Effects of Imatinib in Chronic Myelogenous Leukemia In Vitro.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2956-2956
Author(s):  
Dagmar Bund ◽  
Raymund Buhmann ◽  
Hans-Jochem Kolb
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Myelogenous Leukemia ◽  
Dependent Manner ◽  
Activation Markers ◽  
Antigen Presenting ◽  
Dose Dependent

Abstract Imatinib mesylate, a potent and selective inhibitor of the BCR-ABL tyrosine kinase, has been shown to induce durable haematological and major cytogenetic responses in a high percentage of CML patients. However in most patients the disease recurs, when imatinib is discontinued. In contrast, allogeneic stem cell transplantation (ASCT) is considered to be curative by the immune effect of donor T cells against CML progenitor cells. In this context, the role of imatinib is controversial; it may improve the results of ASCT by reducing the tumour load, it may also reduce the effect of donor lymphocyte transfusions (DLT) by impairing the function of T cells and the capacity of myeloid cells to present antigen. Patient derived CML-cells were studied for the stimulation of allogeneic HLA-matched and mismatched T-cells in the presence and absence of imatinib. In a 5 day culture the proliferative response of HLA-mismatched T cells was evaluated in presence of different concentrations of imatinib (0, 1, 2, or 5 micro M) and various responder-to-stimulator ratios. Thereby, proliferation was detected via a CFDA based assays and the activation profile (CD25, CD69) of the T-cells was determined by FACS. Cr51-release assays were performed after a 7 day culture of CML cells with HLA-matched T cells to test cytotoxicity of CD8+ T-cells. In addition, we characterized the antigen-presenting profile (CD14, CD33, HLA-DR, CD40, CD80, CD86, CD54, CD58) of the CML cells over a 5 day culture with and without imatinib. The presence of imatinib inhibited the proliferative capacity of allogeneic T-cells in a dose-dependent manner. Also, the expression of T cell activation markers was reduced in the presence of the different imatinib concentrations. Preincubation of CML cells with imatinib for 48 hours strengthened the effect on proliferation and activation of T cells. Moreover, imatinib impaired the cytotoxic function of T-cell (HLA-matched setting; CR51-release assay) also in a dose-dependent manner. Finally, the antigen-presenting profile of the myeloid leukemia cells was down regulated by increasing concentrations of imatinib. In summary, imatinib may interfere with the T cellular immune response and the antigen presenting profile on the CML cells in vitro. These results may have an impact on new strategies of treatment of CML with immunotherapy.

scholarly journals BRAF and MEK Inhibitors Affect Dendritic-Cell Maturation and T-Cell Stimulation

2021 ◽  
Vol 22 (21) ◽  
pp. 11951
Author(s):  
Stefanie Hoyer ◽  
Valentina Eberlein ◽  
Gerold Schuler ◽  
Carola Berking ◽  
Lucie Heinzerling ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Single Agent ◽  
Mek Inhibitor ◽  
Dendritic Cell Maturation ◽  
Cytokine Secretion ◽  
Activation Markers ◽  
Surface Marker Expression

BRAF and MEK inhibitor (BRAFi/MEKi) combinations are currently the standard treatment for patients with BRAFV600 mutant metastatic melanoma. Since the RAS/RAF/MEK/ERK-pathway is crucial for the function of different immune cells, we postulated an effect on their function and thus interference with anti-tumor immunity. Therefore, we examined the influence of BRAFi/MEKi, either as single agent or in combination, on the maturation of monocyte-derived dendritic cells (moDCs) and their interaction with T cells. DCs matured in the presence of vemurafenib or vemurafenib/cobimetinib altered their cytokine secretion and surface marker expression profile. Upon the antigen-specific stimulation of CD8+ and CD4+ T cells with these DCs or with T2.A1 cells in the presence of BRAFi/MEKi, we detected a lower expression of activation markers on and a lower cytokine secretion by these T cells. However, treatment with any of the inhibitors alone or in combination did not change the avidity of CD8+ T cells in peptide titration assays with T2.A1 cells. T-helper cell/DC interaction is a bi-directional process that normally results in DC activation. Vemurafenib and vemurafenib/cobimetinib completely abolished the helper T-cell-mediated upregulation of CD70, CD80, and CD86 but not CD25 on the DCs. The combination of dabrafenib/trametinib affected DC maturation and activation as well as T-cell activation less than combined vemurafenib/cobimetinib did. Hence, for a potential combination with immunotherapy, our data indicate the superiority of dabrafenib/trametinib treatment.

scholarly journals pMHC affinity controls duration of CD8+ T cell–DC interactions and imprints timing of effector differentiation versus expansion

2016 ◽  
Vol 213 (12) ◽  
pp. 2811-2829 ◽  
Author(s):  
Aleksandra J. Ozga ◽  
Federica Moalli ◽  
Jun Abe ◽  
Jim Swoger ◽  
James Sharpe ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Effector T Cells ◽  
Dependent Manner ◽  
Functional Avidity ◽  
High Affinity ◽  
Avidity Maturation

During adaptive immune responses, CD8+ T cells with low TCR affinities are released early into the circulation before high-affinity clones become dominant at later time points. How functional avidity maturation is orchestrated in lymphoid tissue and how low-affinity cells contribute to host protection remains unclear. In this study, we used intravital imaging of reactive lymph nodes (LNs) to show that T cells rapidly attached to dendritic cells irrespective of TCR affinity, whereas one day later, the duration of these stable interactions ceased progressively with lowering peptide major histocompatibility complex (pMHC) affinity. This correlated inversely BATF (basic leucine zipper transcription factor, ATF-like) and IRF4 (interferon-regulated factor 4) induction and timing of effector differentiation, as low affinity–primed T cells acquired cytotoxic activity earlier than high affinity–primed ones. After activation, low-affinity effector CD8+ T cells accumulated at efferent lymphatic vessels for egress, whereas high affinity–stimulated CD8+ T cells moved to interfollicular regions in a CXCR3-dependent manner for sustained pMHC stimulation and prolonged expansion. The early release of low-affinity effector T cells led to rapid target cell elimination outside reactive LNs. Our data provide a model for affinity-dependent spatiotemporal orchestration of CD8+ T cell activation inside LNs leading to functional avidity maturation and uncover a role for low-affinity effector T cells during early microbial containment.

scholarly journals Targeting CD38 is lethal to Breg-like chronic lymphocytic leukemia cells and Tregs, but restores CD8+ T-cell responses

2020 ◽  
Vol 4 (10) ◽  
pp. 2143-2157 ◽  
Author(s):  
Alak Manna ◽  
Timothy Kellett ◽  
Sonikpreet Aulakh ◽  
Laura J. Lewis-Tuffin ◽  
Navnita Dutta ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Chronic Lymphocytic Leukemia ◽  
Cd8 T Cells ◽  
Mononuclear Cells ◽  
Transforming Growth Factor ◽  
Ex Vivo ◽  
Xenograft Model ◽  
Lymphocytic Leukemia ◽  
Dependent Manner

Abstract Patients with chronic lymphocytic leukemia (CLL) are characterized by monoclonal expansion of CD5+CD23+CD27+CD19+κ/λ+ B lymphocytes and are clinically noted to have profound immune suppression. In these patients, it has been recently shown that a subset of B cells possesses regulatory functions and secretes high levels of interleukin 10 (IL-10). Our investigation identified that CLL cells with a CD19+CD24+CD38hi immunophenotype (B regulatory cell [Breg]–like CLL cells) produce high amounts of IL-10 and transforming growth factor β (TGF-β) and are capable of transforming naive T helper cells into CD4+CD25+FoxP3+ T regulatory cells (Tregs) in an IL-10/TGF-β-dependent manner. A strong correlation between the percentage of CD38+ CLL cells and Tregs was observed. CD38hi Tregs comprised more than 50% of Tregs in peripheral blood mononuclear cells (PBMCs) in patients with CLL. Anti-CD38 targeting agents resulted in lethality of both Breg-like CLL and Treg cells via apoptosis. Ex vivo, use of anti-CD38 monoclonal antibody (mAb) therapy was associated with a reduction in IL-10 and CLL patient-derived Tregs, but an increase in interferon-γ and proliferation of cytotoxic CD8+ T cells with an activated phenotype, which showed an improved ability to lyse patient-autologous CLL cells. Finally, effects of anti-CD38 mAb therapy were validated in a CLL–patient-derived xenograft model in vivo, which showed decreased percentage of Bregs, Tregs, and PD1+CD38hiCD8+ T cells, but increased Th17 and CD8+ T cells (vs vehicle). Altogether, our results demonstrate that targeting CD38 in CLL can modulate the tumor microenvironment; skewing T-cell populations from an immunosuppressive to immune-reactive milieu, thus promoting immune reconstitution for enhanced anti-CLL response.

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