Tumor Inhibition by DepoVax-Based Cancer Vaccine Is Accompanied by Reduced Regulatory/Suppressor Cell Proliferation and Tumor Infiltration

A successful cancer vaccine needs to overcome the effects of immune-suppressor cells such as Treg lymphocytes, suppressive cytokine-secreting Tr1 cells, and myeloid-derived suppressor cells (MDSCs), while enhancing tumor-specific immune responses. Given the relative poor efficacy associated with current cancer vaccines, a novel vaccine platform called DepoVaxTM (DPX) was developed. C3 tumor-challenged mice were immunized with HPV-E7 peptide in DPX- or conventional-emulsion- (CE-) based vaccine. While control mice showed marked increase in Treg/MDSCs in spleen and blood, in mice treated with DPX-E7 the levels remained similar to tumor-free naive mice. Such differences were also seen within the tumor. Antigen-specific IL10-secreting CD4/CD8 T cells and TGF-β+CD8+ T cell frequencies were increased significantly in CE-treated and control mice in contrast to DPX-E7-immunized mice. Analysis of tumor-infiltrating cells revealed higher frequency of suppressor cells in untreated controls than in DPX-E7 group while the converse was true for tumor-infiltrating CD8 T cells. Immunization of tumor-bearing HLA-A2 transgenic mice with human vaccine DPX-0907, a peptide-based vaccine for breast/ovarian/prostate cancers, showed efficient induction of immune response to cancer peptides despite the presence of suppressor cells. Thus, this study provides the rationale for using DPX-based cancer vaccines in immune-suppressed cancer patients, to induce effective anticancer immunity.

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T-cell subsets and suppressor cells in human bone marrow

Blood ◽

10.1182/blood.v80.12.3242.3242 ◽

1992 ◽

Vol 80 (12) ◽

pp. 3242-3250 ◽

Cited By ~ 48

Author(s):

IG Schmidt-Wolf ◽

S Dejbakhsh-Jones ◽

N Ginzton ◽

P Greenberg ◽

S Strober

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Suppressor Cells ◽

Suppressor Cell ◽

Low Density ◽

Hematopoietic Progenitors ◽

Density Fractions ◽

Alpha Beta

Abstract To characterize immune suppressive and hematopoietic features of enriched subsets of human marrow cells, we separated these cells on Percoll density gradients. CD4+ and CD8+ T cells (CD3+) were enriched in the high-density marrow cell fractions and reduced in low-density fractions. CD4-CD8- (CD3+) T cells expressing the alpha beta T-cell antigen receptor were at least 10 times less numerous than the CD4+ and CD8+ T cells in all fractions. Purified populations of the CD4-CD8- alpha beta + T cells obtained by flow cytometry suppressed the mixed leukocyte reaction (MLR). Another population of suppressor cells that expressed neither T-cell (CD3) nor natural killer cell (CD16) surface markers was also identified. The latter cells had the phenotypic and functional characteristics of “natural suppressor” cells. Suppressor cell activity was enriched in the low-density fractions along with hematopoietic progenitors (colony-forming unit-granulocyte-macrophage and burst-forming unit-erythroid). The progenitor and suppressor cell activities were depleted in high-density fractions. The latter fractions made vigorous responses in the MLR. The low-density fractions, which accounted for less than 10% of the input marrow cells, suppressed the MLR and did not respond. Further evaluation of the low-density fractions may be of value in allogeneic bone marrow transplantation due to the reduction of CD4+ and CD8+ T cells and the enrichment of hematopoietic progenitors as well as immune suppressor cells that may inhibit graft-versus-host disease.

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141 PBMC-based cancer vaccines generated with microfluidics squeezing demonstrate synergistic and durable tumor reduction in combination with PD1 checkpoint and FAP targeted IL-2 variants

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0141 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A155-A155

Author(s):

Matthew Booty ◽

Adam Stockmann ◽

Olivia Pryor ◽

Melissa Myint ◽

Christine Trumpfheller ◽

...

Keyword(s):

T Cells ◽

Combination Therapy ◽

Median Survival ◽

Cancer Vaccine ◽

Cd8 T Cells ◽

Cancer Vaccines ◽

Tumor Model ◽

Mechanistic Study ◽

Engineering System ◽

Tumor Implant

BackgroundWe engineered unfractionated peripheral blood mononuclear cells (PBMCs) to function as antigen presenting cells (APCs) that generate potent CD8+ T cell responses. We investigated the combined efficacy of PBMC-based cancer vaccine with targeted interleukin 2 variants (IL2v); anti-Programmed Cell Death Protein 1 (muPD1-IL2v) and anti-Fibroblast Activation Protein (muFAP-IL2v).MethodsWe generated PBMC-based cancer vaccine with microfluidic cell engineering system (Cell Squeeze®), which facilitates direct cytosolic antigen delivery and enables cell subsets within PBMCs to function as APCs. The immunocytokines used contain IL2v fused with antibody counterparts that enable targeting to tumor-associated stroma or immune cells (aFAP and aPD-1, respectively) with modified FcR binding. The IL2v moiety, compared with wild-type IL-2, has abolished binding to IL-2Ra (CD25) resulting in IL-2Rgb binding only, thus fully maintaining activity on NK and CD8+ T cells, while avoiding Treg activity and CD25 mediated toxicity.ResultsIn the murine TC-1 HPV tumor model, SQZ-PBMC-based vaccines show efficacy as monotherapy (1e6 cells administered iv on day 14 post-tumor implant), while SQZ combination therapy with targeted immunocytokines, muPD1-IL2v and muFAP-IL2v (2 mg/kg or 1 mg/kg, respectively, administered iv on days 21, 28, and 35 post-tumor implant) significantly delayed tumor growth and improved survival in murine TC-1 HPV tumor model. Median survival of combination treated groups remained undefined at day 84 post-tumor implant, while the monotherapy treated groups had calculated median survival times of 36.5, 42, and 70 days for the muFAP-IL2v, muPD1-IL2v, and SQZ monotherapy groups, respectively. Following initial tumor clearance, tumor-free mice (2/12 animals for SQZ monotherapy; 8/12 animals for SQZ with muFAP-IL2v; 11/11 animals for SQZ with muPD1-IL2v) were all re-challenged at day 84 and all remained tumor free at least 7 weeks post re-challenge, suggesting the generation of anti-tumor memory response. In a mechanistic study, SQZ-PBMCs in combination with muPD1-IL2v resulted in increased expansion of intra-tumoral, antigen-specific CD8+ T cells compared with separate administration of either therapy (~3.6-fold over SQZ alone; ~2000-fold over muPD1-IL2v alone; per mg of tumor). Combination therapy also resulted in improved IFNγ and TNFα cytokine production by SQZ-elicited CD8+ T cells (~1.7-fold and ~9-fold, respectively, over SQZ monotherapy).ConclusionsMonotherapy with SQZ-PBMC-based cancer vaccines can drive anti-tumor responses in murine systems. These responses are enhanced by combined administration of targeted immunocytokines. Monotherapy with SQZ-PBMC-HPV is currently under clinical evaluation for HPV16+ tumor indications. These preclinical data support the combination of SQZ-PBMC with FAP-IL2v or PD1-IL2v targeted immunocytokine as promising cancer immunotherapies.

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T-cell subsets and suppressor cells in human bone marrow

Blood ◽

10.1182/blood.v80.12.3242.bloodjournal80123242 ◽

1992 ◽

Vol 80 (12) ◽

pp. 3242-3250 ◽

Cited By ~ 1

Author(s):

IG Schmidt-Wolf ◽

S Dejbakhsh-Jones ◽

N Ginzton ◽

P Greenberg ◽

S Strober

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Suppressor Cells ◽

Suppressor Cell ◽

Low Density ◽

Hematopoietic Progenitors ◽

Density Fractions ◽

Alpha Beta

To characterize immune suppressive and hematopoietic features of enriched subsets of human marrow cells, we separated these cells on Percoll density gradients. CD4+ and CD8+ T cells (CD3+) were enriched in the high-density marrow cell fractions and reduced in low-density fractions. CD4-CD8- (CD3+) T cells expressing the alpha beta T-cell antigen receptor were at least 10 times less numerous than the CD4+ and CD8+ T cells in all fractions. Purified populations of the CD4-CD8- alpha beta + T cells obtained by flow cytometry suppressed the mixed leukocyte reaction (MLR). Another population of suppressor cells that expressed neither T-cell (CD3) nor natural killer cell (CD16) surface markers was also identified. The latter cells had the phenotypic and functional characteristics of “natural suppressor” cells. Suppressor cell activity was enriched in the low-density fractions along with hematopoietic progenitors (colony-forming unit-granulocyte-macrophage and burst-forming unit-erythroid). The progenitor and suppressor cell activities were depleted in high-density fractions. The latter fractions made vigorous responses in the MLR. The low-density fractions, which accounted for less than 10% of the input marrow cells, suppressed the MLR and did not respond. Further evaluation of the low-density fractions may be of value in allogeneic bone marrow transplantation due to the reduction of CD4+ and CD8+ T cells and the enrichment of hematopoietic progenitors as well as immune suppressor cells that may inhibit graft-versus-host disease.

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Tumor and Peripheral Immune Status in Soft Tissue Sarcoma: Implications for Immunotherapy

Cancers ◽

10.3390/cancers13153885 ◽

2021 ◽

Vol 13 (15) ◽

pp. 3885

Author(s):

Luana Madalena Sousa ◽

Jani Sofia Almeida ◽

Tânia Fortes-Andrade ◽

Manuel Santos-Rosa ◽

Paulo Freitas-Tavares ◽

...

Keyword(s):

T Cells ◽

Soft Tissue ◽

Cd8 T Cells ◽

Soft Tissue Sarcomas ◽

Suppressor Cells ◽

Response To Therapy ◽

Immune Checkpoints ◽

Soluble Factors ◽

Lymphocyte To Monocyte Ratio ◽

Immune Related Genes

Soft Tissue Sarcomas (STS) are a heterogeneous and rare group of tumors. Immune cells, soluble factors, and immune checkpoints are key elements of the complex tumor microenvironment. Monitoring these elements could be used to predict the outcome of the disease, the response to therapy, and lead to the development of new immunotherapeutic approaches. Tumor-infiltrating B cells, Natural Killer (NK) cells, tumor-associated neutrophils (TANs), and dendritic cells (DCs) were associated with a better outcome. On the contrary, tumor-associated macrophages (TAMs) were correlated with a poor outcome. The evaluation of peripheral blood immunological status in STS could also be important and is still underexplored. The increased lymphocyte-to-monocyte ratio (LMR) and neutrophil-to-lymphocyte ratio (NLR), higher levels of monocytic myeloid-derived suppressor cells (M-MDSCs), and Tim-3 positive CD8 T cells appear to be negative prognostic markers. Meanwhile, NKG2D-positive CD8 T cells were correlated with a better outcome. Some soluble factors, such as cytokines, chemokines, growth factors, and immune checkpoints were associated with the prognosis. Similarly, the expression of immune-related genes in STS was also reviewed. Despite these efforts, only very little is known, and much research is still needed to clarify the role of the immune system in STS.

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The critical immunosuppressive effect of MDSC-derived exosomes in the tumor microenvironment

10.1101/2020.03.05.979195 ◽

2020 ◽

Cited By ~ 3

Author(s):

Mohammad H. Rashid ◽

Thaiz F. Borin ◽

Roxan Ara ◽

Raziye Piranlioglu ◽

Bhagelu R. Achyut ◽

...

Keyword(s):

T Cells ◽

Tumor Microenvironment ◽

Tumor Growth ◽

Cd8 T Cells ◽

Suppressor Cells ◽

Cell Types ◽

Biological Macromolecules

AbstractMyeloid-derived suppressor cells (MDSCs) are an indispensable component of the tumor microenvironment (TME), and our perception regarding the role of MDSCs in tumor promotion is attaining extra layer of intricacy in every study. In conjunction with MDSC’s immunosuppressive and anti-tumor immunity, they candidly facilitate tumor growth, differentiation, and metastasis in several ways that yet to be explored. Alike any other cell types, MDSCs also release a tremendous amount of exosomes or nanovesicles of endosomal origin and partake in intercellular communications by dispatching biological macromolecules. There has not been any experimental study done to characterize the role of MDSCs derived exosomes (MDSC exo) in the modulation of TME. In this study, we isolated MDSC exo and demonstrated that they carry a significant amount of proteins that play an indispensable role in tumor growth, invasion, angiogenesis, and immunomodulation. We observed higher yield and more substantial immunosuppressive potential of exosomes isolated from MDSCs in the primary tumor area than those are in the spleen or bone marrow. Our in vitro data suggest that MDSC exo are capable of hyper activating or exhausting CD8 T-cells and induce reactive oxygen species production that elicits activation-induced cell death. We confirmed the depletion of CD8 T-cells in vivo by treating the mice with MDSC exo. We also observed a reduction in pro-inflammatory M1-macrophages in the spleen of those animals. Our results indicate that immunosuppressive and tumor-promoting functions of MDSC are also implemented by MDSC-derived exosomes which would open up a new avenue of MDSC research and MDSC-targeted therapy.

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Metabolomic profiling of tumor-infiltrating macrophages during tumor growth

Cancer Immunology Immunotherapy ◽

10.1007/s00262-020-02622-8 ◽

2020 ◽

Vol 69 (11) ◽

pp. 2357-2369

Author(s):

Naoki Umemura ◽

Masahiro Sugimoto ◽

Yusuke Kitoh ◽

Masanao Saio ◽

Hiroshi Sakagami

Keyword(s):

T Cells ◽

Tumor Growth ◽

Cd8 T Cells ◽

Early Stage ◽

Suppressor Cells ◽

Tca Cycle ◽

Tumor Stage ◽

Cell Number ◽

Tumor Bearing ◽

Intracellular Metabolism

Abstract Myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) are both key immunosuppressive cells that contribute to tumor growth. Metabolism and immunity of tumors depend on the tumor microenvironment (TME). However, the intracellular metabolism of MDSCs and TAMs during tumor growth remains unclear. Here, we characterized CD11b+ cells isolated from a tumor-bearing mouse model to compare intratumoral TAMs and intrasplenic MDSCs. Intratumoral CD11b+ cells and intrasplenic CD11b+ cells were isolated from tumor-bearing mice at early and late stages (14 and 28 days post-cell transplantation, respectively). The cell number of intrasplenic CD11b+ significantly increased with tumor growth. These cells included neutrophils holding segmented leukocytes or monocytes with an oval nucleus and Gr-1hi IL-4Rαhi cells without immunosuppressive function against CD8 T cells. Thus, these cells were classified as MDSC-like cells (MDSC-LCs). Intratumoral CD11b+ cells included macrophages with a round nucleus and were F4/80hi Gr-1lo IL-4Rαhi cells. Early stage intratumoral CD11b+ cells inhibited CD8 T cells via TNFα. Thus, this cell population was classified as TAMs. Metabolomic analyses of intratumoral TAMs and MDSC-LCs during tumor growth were conducted. Metabolic profiles of intratumoral TAMs showed larger changes in various metabolic pathways, e.g., glycolysis, TCA cycle, and glutamic acid pathways, during tumor growth compared with MDSL-LCs. Our findings demonstrated that intratumoral TAMs showed an immunosuppressive capacity from the early tumor stage and underwent intracellular metabolism changes during tumor growth. These results clarify the intracellular metabolism of TAMs during tumor growth and contribute to our understanding of tumor immunity.

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452 Combination treatment using KISIMATM protein-based cancer vaccine and systemic STING agonist results in profound modulation of tumor microenvironment and improved tumor control

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0452 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A479-A479

Author(s):

Matteo Rossi ◽

Elodie Belnoue ◽

Susanna Carboni ◽

Wilma Besson-Di Berardino ◽

Erika Riva ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

Tumor Microenvironment ◽

Combination Therapy ◽

Cancer Vaccine ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Tumor Control ◽

Therapeutic Vaccination ◽

Potent Tumor

BackgroundKISIMATM platform allows the development of protein-based cancer vaccines able to induce a potent, tumor-specific CD8 and CD4 T cells response. While the cell penetrating peptide and the Anaxa portions confer, respectively, the cell delivery and self-adjuvanticity properties, the multiantigenic domain allows the targeting of different cancer antigens, resulting in anti-tumoral efficacy in different murine models.1 The first clinical candidate developed from KISIMATM is currently tested, together with anti-PD-1 blockade, in a phase I study in metastatic colorectal cancer patients. Stimulator of interferon genes agonists (STINGa) were shown to induce a potent type I interferon response in preclinical studies. The intratumoral administration of STINGa, to promote tumor inflammation, was shown to result in a protective spontaneous immune response in several murine tumor models. However, the encouraging preclinical results are not supported by recent clinical data, challenging the efficacy of unspecific monotherapy.As it is more and more clear that an effective cancer immunotherapy will require the combination of different treatment strategies, we investigate here the efficacy of combining KISIMATM cancer vaccine with STINGa treatment.MethodsMice were vaccinated with subcutaneous (s.c.) injection of KISIMATM vaccine combined with s.c. administration of STINGa. Safety and immunogenicity were assessed by measuring temperature, serum cytokines and the peripheral antigen-specific response. Anti-tumoral efficacy as well as in depth monitoring of TILs and tumor microenvironment modulation were assessed following therapeutic vaccination in a HPV16 E6 and E7 expressing TC-1 cold tumor model.ResultsCombination treatment was well tolerated and promoted the development of circulating antigen-specific CD8 T cells. In TC-1 tumor bearing mice, KISIMATM therapeutic vaccination resulted in the infiltration of both antigen-specific CD8 and CD4 T cells within the tumor, as well as a switch of tumor associated macrophages polarization toward the more inflammatory type 1. Combination therapy further increased the tumor microenvironment modulation induced by KISIMATM vaccine, promoting the polarization of inflammatory Thelper 1 CD4 T cells and increasing the effector function of antigen-specific CD8 T cells. The profound modulation of the tumor microenvironment induced by combination therapy enhanced the beneficial effect of KISIMATM vaccination, resulting in a prolonged tumor control.ConclusionsCombination of KISIMATM cancer vaccine with systemic STINGa treatment induces the development of a potent, tumor-specific immune response resulting in a profound modulation of the TME. As check-point inhibitor (CPI) therapy is ineffective on poorly infiltrated tumors, combination with therapies able to highly enhance tumor infiltration by T cells could expand CPI indications.Ethics ApprovalThe study was approved by the Canton of Geneva Ethic Board, under the license number GE165/19ReferenceBelnoue E, et al. Targeting self and neo-epitopes with a modular self-adjuvanting cancer vaccine. JCI Insight 2019. 4:11.

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A microbial-based cancer vaccine for induction of EGFRvIII-specific CD8+ T cells and anti-tumor immunity

PLoS ONE ◽

10.1371/journal.pone.0209153 ◽

2019 ◽

Vol 14 (1) ◽

pp. e0209153 ◽

Cited By ~ 6

Author(s):

Lauren Zebertavage ◽

Shelly Bambina ◽

Jessica Shugart ◽

Alejandro Alice ◽

Kyra D. Zens ◽

...

Keyword(s):

T Cells ◽

Tumor Immunity ◽

Cancer Vaccine ◽

Cd8 T Cells

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Intranasal Therapeutic Peptide Vaccine Promotes Efficient Induction and Trafficking of Cytotoxic T Cell Response for the Clearance of HPV Vaginal Tumors

Vaccines ◽

10.3390/vaccines8020259 ◽

2020 ◽

Vol 8 (2) ◽

pp. 259

Author(s):

Gloria Sierra ◽

Stephanie Dorta-Estremera ◽

Venkatesh L. Hegde ◽

Sita M. K. Nookala ◽

Ananta V. Yanamandra ◽

...

Keyword(s):

T Cells ◽

Cd8 T Cells ◽

Peptide Vaccine ◽

Therapeutic Vaccine ◽

Unmet Need ◽

Suppressor Cells ◽

T Cell Response ◽

Cytotoxic T Cell ◽

Intranasal Route ◽

Current Standard

Human papillomavirus (HPV)-induced cancers continue to affect millions of women around the world, and the five year survival rate under the current standard of care for these cancers is less than 60% in some demographics. Therefore there is still an unmet need to develop an effective therapy that can be easily administered to treat established HPV cervical cancer lesions. We sought to investigate the potential of an intranasal HPV peptide therapeutic vaccine incorporating the combination of α-Galactosylceramide (α-GalCer) and CpG-ODN adjuvants (TVAC) against established HPV genital tumors in a syngeneic C57BL/6J mouse model. We obtained evidence to show that TVAC, delivered by the mucosal intranasal route, induced high frequencies of antigen-specific CD8 T cells concurrent with significant reduction in the immunosuppressive regulatory T cells and myeloid derived suppressor cells in the tumor microenvironment (TME), correlating with sustained elimination of established HPV genital tumors in over 85% of mice. Inclusion of both the adjuvants in the vaccine was necessary for significant increase of antigen-specific CD8 T cells to the tumor and antitumor efficacy because vaccination incorporating either adjuvant alone was inefficient. These results strongly support the utility of the TVAC administered by needle-free intranasal route as a safe and effective strategy for the treatment of established genital HPV tumors.

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