scholarly journals 254 NTX-1088, a potent anti-PVR Mab induces DNAM1-mediated antitumor immunity

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A275-A275
Author(s):  
Anas Atieh ◽  
Akram Obiedat ◽  
Guy Cinamon ◽  
Tihana Lenac Rovis ◽  
Paola Kucan Brlic ◽  
...  
Keyword(s):  
T Cells ◽  
Synergistic Effect ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Cd8 T Cells ◽  
Immune Activation ◽  
Cell Activation ◽  
Immune Cell ◽  
Checkpoint Inhibitors ◽  
Tumor Growth Inhibition

BackgroundPoliovirus receptor (PVR, CD155) represents a resistance mechanism to approved immune checkpoint inhibitors (ICIs). It is a key regulator of immune activation, that modifies function through multiple mechanisms. Increased PVR expression levels on tumor cells have been associated with resistance to anti-PD-(L)1 therapy, while loss of PVR led to reduced tumor growth. Targeting PVR using mAbs offers an attractive therapeutic approach for patients with advanced cancer, who are not responding to other ICIs.NTX-1088 is a first-in-class, anti-PVR mAb developed for the treatment of solid tumors and will enter clinical trials early 2022. The antibody binds PVR with high affinity, blocks its interactions with TIGIT and CD96, preventing their inhibitory signaling. Moreover, NTX-1088 forte is manifested through its ability to block the critical interaction between PVR and DNAM1 (CD226). This blockade prevents internalization of DNAM1, restores its expression on the surface of immune cells and results in a robust antitumor activity.MethodsNTX-1088 was rigorously tested in vitro and in-vivo. Various cancer cell lines were incubated with immune effector cells from healthy human donors, in the presence of NTX-1088, alone and in combination with anti-PD-1 mAb (pembrolizumab).ResultsNTX-1088 significantly increased immune cell activation, as measured by IFNg release from activated polyclonal CD8+ T cells, induction of CD137 and killing of tumor cells. When tested in combination with pembrolizumab, NTX-1088 further increased all measured activation parameters, suggesting a potential synergistic effect. A synergistic effect was obtained when NTX-1088 was combined with the anti-CD112R mAb, NTX-2R13, superior to TIGIT-CD112R combinations. When compared to anti-TIGIT mAb (tiragolumab), NTX-1088 demonstrated clear superiority in activating T and NK cells as stand-alone agent. Furthermore NTX-1088 in combination with pembrolizumab, was superior to the combination of pembrolizumab with anti-TIGIT.Importantly, NTX-1088 was the only intervention that significantly restored DNAM1 levels, whereas DNAM1 blockade reduced the activity of NTX-1088 to levels comparable to that of anti-TIGIT mAb.Humanized murine models confirmed the above observations; NTX-1088 exhibited a robust tumor growth inhibition, accompanied by significantly higher prevalence of CD137+, DNAM1+, CD8+ T cells, compared to mice treated by other ICIs.ConclusionsThis is the first report of drug-induced DNAM1 restoration and immune activation. NTX-1088 shows, for the first time, exclusive triple mechanism of action, whereby simultaneous and effective blockade of TIGIT and CD96 is complemented by the efficient restoration of DNAM1. This is a step change in antitumor immune activation, which will be validated in the clinic starting early 2022.

Novel HPV-E7 immune modulators to activate HPV-specific T cells to eliminate cervical cancer.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e18027-e18027
Author(s):  
Lihua Shi ◽  
Di Zhang ◽  
Susan Tam ◽  
Man-Cheong Fung
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Growth ◽  
Tumor Cells ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Cell Activity ◽  
Epitope Peptide ◽  
Hpv E7

e18027 Background: Human papilloma virus (HPV) infection can lead to several types of cancers in both men and women. HPV+ tumor cells constitutively express the HPV-E7 antigen which can act as an oncogene to promote tumor growth and malignant transformation. Here, we report the application of novel Tavo Immune Modulator (TIM) biologics molecules which are consisted of a pMHC complex with an epitope peptide derived from HPV-E7 and co-stimulatory modulators of T cell activity. The HPV-E7 TIM molecules can specifically recognize and activate HPV-E7-specific T cells for the elimination of HPV affected cells. Methods: HPV-E7 TIM molecules were engineered as fusion molecules with HLA-A*02:01 MHC complexed with an HPV-E7 (11-20) epitope peptide at the N-termini, and various T cell costimulatory modulators at the C-termini of IgG heavy and light chains. TIM molecules were expressed in Expi293 cells and purified by Protein A affinity chromatography. Specific binding of TIM with HPV-E7 specific T cells was confirmed by immunostaining and flow cytometry. The activation and expansion of antigen specific CD8+ T cells were elucidated in T cell activation and recall assays. Results: HPV-E7 TIM molecules with various T cell co-stimulator molecules were engineered to specifically recognize HPV-specific T cells. Activation of T cells was antigen-specific and depended on the presence of an engineered T cell modulatory component on the TIM framework. The effects of various costimulatory molecules in different combinations on T cell activation were explored and an optimal combination was identified which facilitated high potency antigen-specific T cell activation. Such molecular combinations could facilitate T cell expansion and activation in T cell recall assays. Efficacy of HPV-E7 TIM molecules by inhibiting tumor growth in a syngeneic tumor model is ongoing. Conclusions: This study demonstrates that HPV-E7 TIM molecules selectively recognize and activate HPV-specific CD8+ T cells in the presence of a combination of two T cell costimulatory factors. Such novel biologics provide distinctive approaches in the treatment of HPV-related cancers and warrant further investigation. Additional in vitro and in vivo studies are ongoing to demonstrate the utility in eliminating HPV-infected tumor cells. Full data will be presented at the meeting.

scholarly journals Id1 and PD-1 Combined Blockade Impairs Tumor Growth and Survival of KRAS-mutant Lung Cancer by Stimulating PD-L1 Expression and Tumor Infiltrating CD8+ T Cells

Cancers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3169
Author(s):  
Iosune Baraibar ◽  
Marta Roman ◽  
María Rodríguez-Remírez ◽  
Inés López ◽  
Anna Vilalta ◽  
...  
Keyword(s):  
Lung Cancer ◽  
T Cells ◽  
Tumor Growth ◽  
Lung Adenocarcinoma ◽  
Tumor Cells ◽  
Cd8 T Cells ◽  
Checkpoint Inhibitors ◽  
Combined Therapy ◽  
Tumor Infiltration

The use of PD-1/PD-L1 checkpoint inhibitors in advanced NSCLC is associated with longer survival. However, many patients do not benefit from PD-1/PD-L1 blockade, largely because of immunosuppression. New immunotherapy-based combinations are under investigation in an attempt to improve outcomes. Id1 (inhibitor of differentiation 1) is involved in immunosuppression. In this study, we explored the potential synergistic effect of the combination of Id1 inhibition and pharmacological PD-L1 blockade in three different syngeneic murine KRAS-mutant lung adenocarcinoma models. TCGA analysis demonstrated a negative and statistically significant correlation between PD-L1 and Id1 expression levels. This observation was confirmed in vitro in human and murine KRAS-driven lung cancer cell lines. In vivo experiments in KRAS-mutant syngeneic and metastatic murine lung adenocarcinoma models showed that the combined blockade targeting Id1 and PD-1 was more effective than each treatment alone in terms of tumor growth impairment and overall survival improvement. Mechanistically, multiplex quantification of CD3+/CD4+/CD8+ T cells and flow cytometry analysis showed that combined therapy favors tumor infiltration by CD8+ T cells, whilst in vivo CD8+ T cell depletion led to tumor growth restoration. Co-culture assays using CD8+ cells and tumor cells showed that T cells present a higher antitumor effect when tumor cells lack Id1 expression. These findings highlight that Id1 blockade may contribute to a significant immune enhancement of antitumor efficacy of PD-1 inhibitors by increasing PD-L1 expression and harnessing tumor infiltration of CD8+ T lymphocytes.

scholarly journals Deep immune profiling of MIS-C demonstrates marked but transient immune activation compared to adult and pediatric COVID-19

2021 ◽  
Vol 6 (57) ◽  
pp. eabf7570
Author(s):  
Laura A. Vella ◽  
Josephine R. Giles ◽  
Amy E. Baxter ◽  
Derek A. Oldridge ◽  
Caroline Diorio ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Immune Activation ◽  
Cell Activation ◽  
Vascular Complications ◽  
Adult Disease ◽  
Vasoactive Medication ◽  
Inflammatory Syndrome

Pediatric COVID-19 following SARS-CoV-2 infection is associated with fewer hospitalizations and often milder disease than in adults. A subset of children, however, present with Multisystem Inflammatory Syndrome in Children (MIS-C) that can lead to vascular complications and shock, but rarely death. The immune features of MIS-C compared to pediatric COVID-19 or adult disease remain poorly understood. We analyzed peripheral blood immune responses in hospitalized SARS-CoV-2 infected pediatric patients (pediatric COVID-19) and patients with MIS-C. MIS-C patients had patterns of T cell-biased lymphopenia and T cell activation similar to severely ill adults, and all patients with MIS-C had SARS-CoV-2 spike-specific antibodies at admission. A distinct feature of MIS-C patients was robust activation of vascular patrolling CX3CR1+ CD8+ T cells that correlated with the use of vasoactive medication. Finally, whereas pediatric COVID-19 patients with acute respiratory distress syndrome (ARDS) had sustained immune activation, MIS-C patients displayed clinical improvement over time, concomitant with decreasing immune activation. Thus, non-MIS-C versus MIS-C SARS-CoV-2 associated illnesses are characterized by divergent immune signatures that are temporally distinct from one another and implicate CD8+ T cells in the clinical presentation and trajectory of MIS-C.

scholarly journals Inhibition of the PI3K/mTOR Pathway in Breast Cancer to Enhance Response to Immune Checkpoint Inhibitors in Breast Cancer

2021 ◽  
Vol 22 (10) ◽  
pp. 5207
Author(s):  
Chi Yan ◽  
Jinming Yang ◽  
Nabil Saleh ◽  
Sheau-Chiann Chen ◽  
Gregory D. Ayers ◽  
...  
Keyword(s):  
Breast Cancer ◽  
T Cells ◽  
Tumor Growth ◽  
Cd8 T Cells ◽  
Immune Checkpoint ◽  
Immune Checkpoint Inhibitors ◽  
Checkpoint Inhibitors ◽  
Mtor Pathway ◽  
Complete Regression ◽  
Mtor Inhibition

Objectives: Inhibition of the PI3K/mTOR pathway suppresses breast cancer (BC) growth, enhances anti-tumor immune responses, and works synergistically with immune checkpoint inhibitors (ICI). The objective here was to identify a subclass of PI3K inhibitors that, when combined with paclitaxel, is effective in enhancing response to ICI. Methods: C57BL/6 mice were orthotopically implanted with syngeneic luminal/triple-negative-like PyMT cells exhibiting high endogenous PI3K activity. Tumor growth in response to treatment with anti-PD-1 + anti-CTLA-4 (ICI), paclitaxel (PTX), and either the PI3Kα-specific inhibitor alpelisib, the pan-PI3K inhibitor copanlisib, or the broad spectrum PI3K/mTOR inhibitor gedatolisib was evaluated in reference to monotherapy or combinations of these therapies. Effects of these therapeutics on intratumoral immune populations were determined by multicolor FACS. Results: Treatment with alpelisib + PTX inhibited PyMT tumor growth and increased tumor-infiltrating granulocytes but did not significantly affect the number of tumor-infiltrating CD8+ T cells and did not synergize with ICI. Copanlisib + PTX + ICI significantly inhibited PyMT growth and increased activation of intratumoral CD8+ T cells as compared to ICI alone, yet did not inhibit tumor growth more than ICI alone. In contrast, gedatolisib + ICI resulted in significantly greater inhibition of tumor growth compared to ICI alone and induced durable dendritic-cell, CD8+ T-cell, and NK-cell responses. Adding PTX to this regimen yielded complete regression in 60% of tumors. Conclusion: PI3K/mTOR inhibition plus PTX heightens response to ICI and may provide a viable therapeutic approach for treatment of metastatic BC.

GDF15 expression in metastatic colorectal cancer.

2021 ◽  
Vol 39 (3_suppl) ◽  
pp. 116-116
Author(s):  
Priya Jayachandran ◽  
Joanne Xiu ◽  
Shivani Soni ◽  
Richard M. Goldberg ◽  
Benjamin Adam Weinberg ◽  
...  
Keyword(s):  
Colon Cancer ◽  
T Cells ◽  
Nk Cells ◽  
Chromatin Remodeling ◽  
Cancer Progression ◽  
Cd8 T Cells ◽  
Immune Cell ◽  
Checkpoint Inhibitors ◽  
Metastatic Colon Cancer ◽  
Genomic Alterations

116 Background: Cachexia affects many cancer patients. Growth differentiation factor-15 (GDF15) is a protein that regulates weight and the stress response of cells. The GDF15 gene encodes a ligand of TGF-beta that triggers cachexia and modulates the progression from tumorigenesis to metastasis. Inhibition of GDF15 with an antibody restored muscle mass and fat in animal models. Serum levels rise in proportion to the progression of colon cancer, predict outcome, and have been correlated with CEA. Methods: We retrospectively reviewed 7607 CRC tumors profiled by Caris Life Sciences (Phoenix, AZ) from 2019 to 2020. Profiling included whole transcriptome sequencing (RNA-Seq by NovoSeq). Tumor mutational burden, mismatch repair status, and pathway genomic alterations were evaluated. QuantiSEQ was used to assess immune cell infiltration in the tumor microenvironment. Results: GDF15 expression ranged from 0 to 593 transcripts per million (TPM) with median of 30 (IQR = 15.02). There was no association with age, sex, or primary tumor sidedness. MSI-H/dMMR tumors had higher GDF15 expression (median 37 vs 30, p = 0.0004); TMB > = 17 tumors was seen in 5.9% of bottom quartile (Q1) GDF15 expressors and 8.3% of top quartile (Q4). PDL1 IHC positivity was inversely correlated with GDF15 expression (7.1% in Q1 vs. 2.6% in Q4, p < 0.0001). Genomic alterations associated with higher GDF15 expression (Q4 vs Q1) included genes on TGF-B (SMAD2/4), PI3K (PIK3CA, MTOR), chromatin remodeling (ARID1A, KMT2C), DDR (ATM) and Wnt pathway (APC); those inversely associated included MYC CNA and TP53. Q1 tumors had higher CNA of ERBB2 and FGFR1. Relative neutrophils and NK cells in the TME increased from Q1 to Q4 (p < 0.001). There was a decrease in CD8+ T-cells and Treg cells from Q1 to Q4. Conclusions: GDF15 expression correlates with increased dMMR/MSI-H and TMB, but not with PDL1 expression. Mutations and activated pathways associated with GDF15 expression may explain increased cachexia with more aggressive disease. The association with chromatin remodeling may warrant therapies targeting histone modification and epigenetics. The increase in NK cells but decrease in CD8+ T cells in the TME with increasing GDF15 suggests approaches to treatment. Higher CD8+ lymphocyte counts correlate with PFS with immunotherapy. Anti-PD-L1 therapy reinvigorates the killing function of CD8+ T cells. The decrease in CD8+ T cells and PDL1 positivity with rising GDF15 suggests worse outcome and a lack of response to anti-PDL1 therapy. NK cell checkpoint inhibitors, CARs, and an anti-GFRAL antibody are now in clinical trials and might be utilized in high GDF15 cancers. GDF15 is emerging as a target in the treatment of obesity and cachexia and as a prognostic marker in oncology. Understanding its expression in metastatic colon cancer may reveal which patients could benefit from developing anti-GDF15 targeted therapies against cancer progression.

scholarly journals Identification of distinct immune activation profiles in adult humans

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Renaud Cezar ◽  
Audrey Winter ◽  
Delphine Desigaud ◽  
Manuela Pastore ◽  
Lucy Kundura ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Activation ◽  
Cell Activation ◽  
Immune Cell ◽  
Nk Cell ◽  
Liver Steatosis ◽  
Treg Cells ◽  
Microbial Translocation ◽  
Color Flow

AbstractLatent infectious agents, microbial translocation, some metabolites and immune cell subpopulations, as well as senescence modulate the level and quality of activation of our immune system. Here, we tested whether various in vivo immune activation profiles may be distinguished in a general population. We measured 43 markers of immune activation by 8-color flow cytometry and ELISA in 150 adults, and performed a double hierarchical clustering of biomarkers and volunteers. We identified five different immune activation profiles. Profile 1 had a high proportion of naïve T cells. By contrast, Profiles 2 and 3 had an elevated percentage of terminally differentiated and of senescent CD4+ T cells and CD8+ T cells, respectively. The fourth profile was characterized by NK cell activation, and the last profile, Profile 5, by a high proportion of monocytes. In search for etiologic factors that could determine these profiles, we observed a high frequency of naïve Treg cells in Profile 1, contrasting with a tendency to a low percentage of Treg cells in Profiles 2 and 3. Moreover, Profile 5 tended to have a high level of 16s ribosomal DNA, a direct marker of microbial translocation. These data are compatible with a model in which specific causes, as the frequency of Treg or the level of microbial translocation, shape specific profiles of immune activation. It will be of interest to analyze whether some of these profiles drive preferentially some morbidities known to be fueled by immune activation, as insulin resistance, atherothrombosis or liver steatosis.

Generation of CD8 T Cell-Mediated Protective Immunity against Tumor Escapees

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2623-2623 ◽  
Author(s):  
Bindu Varghese ◽  
Behnaz Taidi ◽  
Adam Widman ◽  
James Do ◽  
R. Levy
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Cd8 T Cells ◽  
Cell Lymphoma ◽  
Ex Vivo ◽  
B Cell Lymphoma ◽  
Cd8 T Cell

Abstract Introduction: Anti-idiotype antibodies against B cell lymphoma have shown remarkable success in causing tumor regression in the clinic. In addition to their known ability to mediate ADCC, anti-idiotype antibodies have also been shown to directly inhibit the proliferation of tumor cells by sending negative growth signals via the target idiotype. However, further studies to investigate this mechanism have been hindered by the failure of patient tumor cells to grow ex vivo. Methods and Results: In order to study this phenomenon further, we developed an antibody against the idiotype on an A20 mouse B lymphoma cell line. A radioactive thymidine incorporation assay showed decreased A20 cell proliferation in the presence of the anti-id antibody ex vivo. In vivo, when mice were treated intraperitoneally (i.p.) with 100 μg of antibody 3 hours post-tumor inoculation (1×106 A20 subcutaneously (s.c.)), tumor growth was delayed for greater than 40 days after which the tumor began to grow once again. Further analysis of these escaping tumor cells by flow cytometry showed that that the tumor cells escaped the antibody-mediated immune response by down-regulating expression of idiotype and IgG on their surfaces although the cells retained idiotype expression intracellularly. This down-regulation of surface idiotype rendered the tumor cells resistant to both ADCC and signaling-induced cell death. The addition of an immunostimulatory bacterial mimic (CpG-DNA; 100 μg × 5 intratumoral (i.t.) injections; Days 2, 3 4, 6 & 8) to antibody therapy (Day 0; 100 μg i.p.) cured large established tumors (Day 0 = 1 cm2) and prevented the occurrence of tumor escapees (p&lt;0.0001). Antibody plus CpG combination therapy in tumor-bearing mice deficient for CD8+ T cells demonstrated the critical role of CD8+ T cells in A20 tumor eradication (p&lt;0.005). Depletion of CD4+ T cells was found to have no significant impact on the therapy. We also found that when mice were inoculated with two tumors and treated with anti-idiotype antibody (i.p.) followed by intratumoral CpG in just one tumor (Day 0=1 cm2; anti-idiotype antibody 100 μg Day 0; 100 μg CpG Days 2, 3, 4, 6 & 8), untreated tumors regressed just as well as CpG-treated tumors indicating a systemic anti-tumor immune response was generated. Conclusion: Anti-idiotype therapy, although effective in delaying tumor growth, frequently generates antigen-loss variants. However, we found that when anti-idiotype antibodies were combined with CpG, even large established tumors were cured due to systemic CD8+ T cell-dependent tumor immunity. Rather than simply mediating ADCC against a single tumor antigen, which requires the constant infusion of antibody to hamper tumor growth, we hypothesize a cytotoxic T-cell response against many tumor antigens was also generated. Such a diverse T-cell repertoire can prevent the emergence of tumor escapees and collectively provide long-lasting tumor protection. These pre-clinical results suggest that anti-tumor antibodies combined with CpG warrant further study in patients with B cell lymphoma.

Effect of MMP9 inhibition on effector T-cell responses in a PD1-axis refractory model.

2017 ◽  
Vol 35 (7_suppl) ◽  
pp. 104-104
Author(s):  
Victoria Smith ◽  
Vladi Juric ◽  
Amanda Mikels-Vigdal ◽  
Chris O'Sullivan ◽  
Maria Kovalenko ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Tumor Growth ◽  
Cell Activation ◽  
Immune Cell ◽  
Single Agent ◽  
Fold Increase ◽  
Cytotoxic T Cell

104 Background: Matrix metalloproteinase 9 (MMP9) acts via diverse mechanisms to promote tumor growth and metastasis, and is a key component of the immune-suppressive myeloid inflammatory milieu. We developed a monoclonal antibody (AB0046) that inhibits murine MMP9 and assessed its mechanism of action in immunocompetent mice as a single agent, or in combination with a murine anti-PDL1 antibody. Methods: An orthotopic, syngeneic tumor model (NeuT), which models MMP9-positive myeloid infiltrate, was utilized for efficacy and pharmacodynamic studies involving RNA and T cell receptor (TCR) sequencing, and flow cytometry. Enzymatic analyses were performed on T cell chemoattractant CXCR3 ligands (CXCL9, CXCL10, and CXCL11) which were subsequently evaluated in chemotaxis assays. Results: Anti-MMP9 treatment alone or in combination with an anti-PDL1 antibody decreased primary tumor growth as compared to IgG control-treated animals (56% vs 335% tumor growth increase, p = 0.0005) or anti-PDL1 alone. Profiling of tumors by RNA sequencing revealed that inhibition of MMP9 resulted in elevated expression of genes associated with immune cell activation pathways (Hallmark Interferon Gamma Response, FDR p < 0.001). Treatment with anti-MMP9 and anti-PDL1 antibodies decreased TCR clonality, with evidence of a more diverse TCR repertoire (p = 0.005). Immunophenotyping of tumor-associated T cells by flow cytometry showed that anti-MMP9 and anti-PDL1 co-treatment promoted a 2.8-fold increase in CD3+ cells in tumors (p = 0.01), which was associated with an increase in CD4+ T cells (3.2-fold increase; p = 0.006) and CD8+ T cells (2.8-fold increase; p = 0.013). In contrast, anti-MMP9 and combination treatment resulted in a decrease in tumor-associated regulatory T cells (CD25+ FoxP3+ cells, p = 0.04). MMP9 cleavage of T cell chemoattractant ligands in vitro rendered them functionally inactive for recruitment of activated primary human effector T cells. Conclusions: Inhibition of MMP9 reduces tumor burden and promotes cytotoxic T cell infiltration in a PD1-axis refractory mouse model. The combination of nivolumab and GS-5745, a humanized anti-MMP9 inhibitory antibody, is currently being evaluated in gastric cancer (NCT02864381).

scholarly journals The expression of class II major histocompatibility molecules on breast tumors delays T cell exhaustion, expands the T cell repertoire and slows tumor growth

2018 ◽  
Author(s):  
Tyler R. McCaw ◽  
Mei Li ◽  
Dmytro Starenki ◽  
Sara J. Cooper ◽  
Selene Meza-Perez ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
T Cell Exhaustion ◽  
Major Histocompatibility ◽  
Cell Exhaustion ◽  
Mhcii Expression

AbstractThe expression of major histocompatibility complex II (MHCII) on tumor cells correlates with survival and responsiveness to immunotherapy. However, the mechanisms underlying these observations are poorly defined. Using a murine breast tumor line, we tested how MHCII expression affected anti-tumor immunity. We found that MHCII-expressing tumors grew more slowly than controls and recruited more functional CD4+ and CD8+ T cells. Additionally, MHCII-expressing tumors contained more TCR clonotypes expanded to a larger degree than control tumors. Functional CD8+ T cells in tumors depended on CD4+ T cells. However, both CD4+ and CD8+ T cells eventually became exhausted, even in MHCII-expressing tumors. PD1 blockade had no impact on tumor growth, potentially because tumor cells poorly expressed PD-L1. These results suggest tumor cell expression of MHCII facilitates the local activation of CD4+ T cells and indirectly helps the activation and expansion of CD8+ T cells, but by itself, cannot prevent T cell exhaustion.PrécisThe expression of MHCII on tumor cells augments CD4 and CD8 T cell responses, expands the TCR repertoire and delays exhaustion. Hence, strategies to induce MHCII expression may be a powerful adjuvant to immunotherapeutic regimens of solid tumors.

scholarly journals A CCR4 antagonist combined with vaccines induces antigen-specific CD8+ T cells and tumor immunity against self antigens

Blood ◽  
2011 ◽  
Vol 118 (18) ◽  
pp. 4853-4862 ◽  
Author(s):  
Helene Pere ◽  
Yves Montier ◽  
Jagadeesh Bayry ◽  
Francoise Quintin-Colonna ◽  
Nathalie Merillon ◽  
...  
Keyword(s):  
T Cells ◽  
Tumor Growth ◽  
Cd8 T Cells ◽  
Hematologic Malignancies ◽  
Clinical Development ◽  
Peripheral Tolerance ◽  
Tumor Growth Inhibition ◽  
Inhibition Of Tumor Growth ◽  
Therapeutic Settings ◽  
Small Chemical

Abstract Regulatory T cells (Tregs) may impede cancer vaccine efficacy in hematologic malignancies and cancer. CCR4 antagonists, an emergent class of Treg inhibitor, have been shown to block recruitment of Tregs mediated by CCL22 and CCL17. Our aim was to demonstrate the ability of a CCR4 antagonist (a small chemical molecule identified in silico) when combined with vaccines to break peripheral tolerance controlled by Tregs, a prerequisite for the induction of CD8+ T cells against self Ags. Immunization of transgenic or normal mice expressing tumor-associated self Ags (Her2/neu, OVA, gp100) with a CCR4 antagonist combined with various vaccines led to the induction of effector CD8+ T cells and partial inhibition of tumor growth expressing self Ags in both prophylactic and therapeutic settings. The CCR4 antagonist was more efficient than cyclophosphamide to elicit anti-self CD8+ T cells. We also showed that the population of Tregs expressing CCR4 corresponded to memory (CD44high) and activated (ICOS+) Tregs, an important population to be targeted to modulate Treg activity. CCR4 antagonist represents a competitive class of Treg inhibitor able to induce functional anti-self CD8+ T cells and tumor growth inhibition when combined with vaccines. High expression of CCR4 on human Tregs also supports the clinical development of this strategy.

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