Intravenous injection of MVA virus targets CD8+ lymphocytes to tumors to control tumor growth upon combinatorial treatment with a TLR9 agonist

Research progress of MUC1 in genitourinary cancers

MUC1 is a highly glycosylated transmembrane protein with a high molecular weight. It plays a role in lubricating and protecting mucosal epithelium, participates in epithelial cell renewal and differentiation, and regulates cell adhesion, signal transduction, and immune response. MUC1 is expressed in both normal and malignant epithelial cells, and plays an important role in the diagnosis, prognosis prediction and clinical monitoring of a variety of tumors and is expected to be a new therapeutic target. This article reviews the structural features, expression regulation mechanism, and research progress of MUC1 in the development of genitourinary cancers and its clinical applications.

The effect of Toll-like receptor agonists on the immunogenicity of MVA-SARS-2-S vaccine after intranasal administration in mice

Background and aims

Modified Vaccinia virus Ankara (MVA) represents a promising vaccine vector for respiratory administration to induce protective lung immunity including tertiary lymphoid structure, the bronchus-associated lymphoid tissue (BALT). However, MVA expressing the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike protein (MVA-SARS-2-S) required prime-boost administration to induce high titers of anti-Spike antibodies in serum and bronchoalveolar lavage (BAL). As the addition of adjuvants enables efficient tailoring of the immune responses even to live vaccines, we tested whether Toll-like receptor (TLR)-agonists affect immune responses induced by a single dose of intranasally applied MVA-SARS-2-S.

Methods

We intranasally immunized C57BL/6 mice with MVA-SARS-2-S vaccine in the presence of either TLR3 agonist polyinosinic polycytidylic acid [poly(I:C)], TLR4 agonist bacterial lipopolysaccharide (LPS) from Escherichia coli, or TLR9 agonist CpG oligodeoxynucleotide (CpG ODN) 1826. At different time-points after immunization, we analyzed induced immune responses using flow cytometry, immunofluorescent microscopy, and ELISA.

Results

TLR agonists had profound effects on MVA-SARS-2-S-induced immune responses. At day 1 post intranasal application, the TLR4 agonist significantly affected MVA-induced activation of dendritic cells (DCs) within the draining bronchial lymph nodes, increasing the ratio of CD11b+CD86+ to CD103+CD86+ DCs. Nevertheless, the number of Spike-specific CD8+ T cells within the lungs at day 12 after vaccination was increased in mice that received MVA-SARS-2-S co-administered with TLR3 but not TLR4 agonists. TLR9 agonist did neither significantly affect MVA-induced DC activation nor the induction of Spike-specific CD8+ T cells but reduced both number and size of bronchus-associated lymphoid tissue. Surprisingly, the addition of all TLR agonists failed to boost the levels of Spike-specific antibodies in serum and bronchoalveolar lavage.

Conclusions

Our study indicates a potential role of TLR-agonists as a tool to modulate immune responses to live vector vaccines. Particularly TLR3 agonists hold a promise to potentiate MVA-induced cellular immune responses. On the other hand, additional research is necessary to identify optimal combinations of agonists that could enhance MVA-induced humoral responses.

Armored modified vaccinia Ankara in cancer immunotherapy

Cancer immunotherapy relies on unleashing the patient´s immune system against tumor cells. Cancer vaccines aim to stimulate both the innate and adaptive arms of immunity to achieve durable clinical responses. Some roadblocks for a successful cancer vaccine in the clinic include the tumor antigen of choice, the adjuvants employed to strengthen antitumor-specific immune responses, and the risks associated with enhancing immune-related adverse effects in patients. Modified vaccinia Ankara (MVA) belongs to the family of poxviruses and is a versatile vaccine platform that combines several attributes crucial for cancer therapy. First, MVA is an excellent inducer of innate immune responses leading to type I interferon secretion and induction of T helper cell type 1 (Th1) immune responses. Second, it elicits robust and durable humoral and cellular immunity against vector-encoded heterologous antigens. Third, MVA has enormous genomic flexibility, which allows for the expression of multiple antigenic and costimulatory entities. And fourth, its replication deficit in human cells ensures a excellent safety profile. In this review, we summarize the current understanding of how MVA induces innate and adaptive immune responses. Furthermore, we will give an overview of the tumor-associated antigens and immunomodulatory molecules that have been used to armor MVA and describe their clinical use. Finally, the route of MVA immunization and its impact on therapeutic efficacy depending on the immunomodulatory molecules expressed will be discussed.

Intravenous injection of a novel viral immunotherapy encoding human interleukin-7 in nonhuman primates is safe and increases absolute lymphocyte count

Persistence of an immunosuppression, affecting both the innate and adaptive arms of the immune system, plays a role in sepsis patients' morbidity and late mortality pointing to the need for broad and effective immune interventions. MVA-hIL-7-Fc is a non-replicative recombinant Modified Vaccinia virus Ankara encoding the human interleukin-7 fused to human IgG2 Fc fragment. We have shown in murine sepsis models the capacity of this new virotherapy to stimulate both arms of the immune system and increase survival. Herein, an exploratory study in nonhuman primates was performed following a single intravenous injection of the MVA-hIL-7-Fc used at the clinical dose to assess its safety and biological activities. Four cynomolgus macaques were followed for 3 weeks post-injection (p.i), without observed acute adverse reactions. Circulating hIL-7-Fc was detected during the first 3-5 days p.i with a detection peaking at 12 h p.i. IL-7 receptor engagement and downstream signal transduction were detected in T cells demonstrating functionality of the expressed IL-7. Expansion of blood lymphocytes, mainly CD4 and CD8 naïve and central memory T cells, was observed on day 7 p.i. together with a transient increase of Ki67 expression on T lymphocytes. In addition, we observed an increase in circulating B and NK cells as well as monocytes were albeit with different kinetics and levels. This study indicates that a vectorized IL-7-Fc, injected by intravenous route at a relevant clinical dose in a large animal model, is active without adverse reactions supporting the clinical development of this novel virotherapy for treatment of sepsis patients.

Toll-like receptor-targeted anti-tumor therapies: Advances and challenges

Toll-like receptors (TLRs) are pattern recognition receptors, originally discovered to stimulate innate immune reactions against microbial infection. TLRs also play essential roles in bridging the innate and adaptive immune system, playing multiple roles in inflammation, autoimmune diseases, and cancer. Thanks to the immune stimulatory potential of TLRs, TLR-targeted strategies in cancer treatment have proved to be able to regulate the tumor microenvironment towards tumoricidal phenotypes. Quantities of pre-clinical studies and clinical trials using TLR-targeted strategies in treating cancer have been initiated, with some drugs already becoming part of standard care. Here we review the structure, ligand, signaling pathways, and expression of TLRs; we then provide an overview of the pre-clinical studies and an updated clinical trial watch targeting each TLR in cancer treatment; and finally, we discuss the challenges and prospects of TLR-targeted therapy.

Intravenous administration of viral vectors expressing prostate cancer antigens enhances the magnitude and functionality of CD8+ T cell responses

BACKGROUND

The use of immunotherapeutic vaccination in prostate cancer is a promising approach that likely requires the induction of functional, cytotoxic T cells . The experimental approach described here uses a well-studied adenovirus-poxvirus heterologous prime-boost regimen, in which the vectors encode a combination of prostate cancer antigens, with the booster dose delivered by either the intravenous or intramuscular (IM) route. This prime-boost regimen was investigated for antigen-specific CD8+ T cell induction.

METHODS

The coding sequences for four antigens expressed in prostate cancer, 5T4, PSA, PAP, and STEAP1, were inserted into replication-incompetent chimpanzee adenovirus Oxford 1 (ChAdOx1) and into replication-deficient modified vaccinia Ankara (MVA). In four strains of mice, ChAdOx1 prime was delivered intramuscularly, with an MVA boost delivered by either IM or intravenous routes. Immune responses were measured in splenocytes using ELISpot, multiparameter flow cytometry, and a targeted in vivo killing assay.

RESULTS

The prime-boost regimen was highly immunogenic, with intravenous administration of the boost resulting in a sixfold increase in the magnitude of antigen-specific T cells induced and increased in vivo killing relative to the intramuscular boosting route. Prostate-specific antigen (PSA)-specific responses were dominant in all mouse strains studied (C57BL/6, BALBc, CD-1 and HLA-A2 transgenic).

CONCLUSION

This quadrivalent immunotherapeutic approach using four antigens expressed in prostate cancer induced high magnitude, functional CD8+ T cells in murine models. The data suggest that comparing the intravenous versus intramuscular boosting routes is worthy of investigation in humans.

A novel virotherapy encoding human interleukin-7 improves ex vivo T lymphocyte functions in immunosuppressed patients with septic shock and critically ill COVID-19

A majority of patients with sepsis surviving the first days in intensive care units (ICU) enter a state of immunosuppression contributing to their worsening. A novel virotherapy based on the non-propagative Modified Virus Ankara (MVA) expressing the human interleukin-7 (hIL-7) cytokine fused to an Fc fragment, MVA-hIL-7-Fc, was developed and shown to enhance innate and adaptive immunity and confer survival advantages in murine sepsis models. Here, we assessed the capacity of hIL-7-Fc produced by the MVA-hIL-7-Fc to improve ex vivo T lymphocyte functions from ICU patients with sepsis. Primary hepatocytes were transduced with the MVA-hIL-7-Fc or an empty MVA, and cell supernatants containing the secreted hIL-7-Fc were harvested for in vitro and ex vivo studies. Whole blood from ICU patients [septic shock = 15, coronavirus disease 2019 (COVID-19) = 30] and healthy donors (n = 36) was collected. STAT5 phosphorylation, cytokine production, and cell proliferation were assessed upon T cell receptor (TCR) stimulation in presence of MVA-hIL-7-Fc-infected cell supernatants. Cells infected by MVA-hIL-7-Fc produced a dimeric, glycosylated, and biologically active hIL-7-Fc. Cell supernatants containing the expressed hIL-7-Fc triggered the IL-7 pathway in T lymphocytes as evidenced by the increased STAT5 phosphorylation in CD3+ cells from patients and healthy donors. The secreted hIL-7-Fc improved Interferon-γ (IFN-γ) and/or Tumor necrosis factor-α (TNF-α) productions and CD4+ and CD8+ T lymphocyte proliferation after TCR stimulation in patients with bacterial and viral sepsis. This study demonstrates the capacity of the novel MVA-hIL-7-Fc-based virotherapy to restore ex vivo T cells immune functions in ICU patients with sepsis and COVID-19, further supporting its clinical development.

Viral Delivery of IL-7 Is a Potent Immunotherapy Stimulating Innate and Adaptive Immunity and Confers Survival in Sepsis Models

Persistence of an immunosuppressive state plays a role in septic patient morbidity and late mortality. Both innate and adaptive pathways are impaired, pointing toward the need for immune interventions targeting both arms of the immune system. We developed a virotherapy using the nonpropagative modified vaccinia virus Ankara (MVA), which harbors the intrinsic capacity to stimulate innate immunity, to deliver IL-7, a potent activator of adaptive immunity. The rMVA-human IL-7 (hIL-7)-Fc encoding the hIL-7 fused to the human IgG2-Fc was engineered and shown to express a dimeric, glycosylated, and biologically active cytokine. Following a single i.v. injection in naive mice, the MVA-hIL-7-Fc increased the number of total and activated B, T, and NK cells but also myeloid subpopulations (Ly6C^high, Ly6C^int, and Ly6C^neg cells) in both lung and spleen. It triggered differentiation of T cells in central memory, effector memory, and acute effector phenotypes and enhanced polyfunctionality of T cells, notably the number of IFN-γ-producing cells. The MVA vector contributed significantly to immune cell activation, particularly of NK cells. The MVA-hIL-7-Fc conferred a significant survival advantage in the cecal ligation and puncture (CLP) and Candida albicans sepsis models. It significantly increased cell numbers and activation in both spleen and lung of CLP mice. Comparatively, in naive and CLP mice, the rhIL-7-Fc soluble counterpart overall induced less vigorous, shorter lasting, and narrower immune activities than did the MVA-hIL-7-Fc and favored TNF-α-producing cells. The MVA-hIL-7-Fc represents a novel class of immunotherapeutic with clinical potential for treatment of septic patients.

MVAΔ008 viral vector encoding the model protein OVA induces improved immune response against the heterologous antigen and equal levels of protection in a mice tumor model than the conventional MVA

Modified vaccinia Ankara virus (MVA) is extensively used as a vaccine vector. We have previously observed that MVAΔ008, an MVA lacking the gene that codes for interleukin-18 binding protein, significantly increases CD8+ and CD4+ T-cell responses to vaccinia virus (VACV) epitopes and recombinant HIV antigens. However, the efficacy of this vector against pathogens or tumor cells remains unclear. Thus, the aim of this study was to evaluate the cellular immune response and the protection induced by recombinant MVAs encoding the model antigen ovalbumin (OVA). We used the MO5 melanoma tumor model (OVA-expressing tumor) as an approach for evaluating the vector-induced efficacy. Our results show that MVAΔ008-OVA (optimized vector) induced higher in vivo specific cytotoxicity and ex vivo T-cell IFN-γ responses against OVA than the conventional MVA vector. Importantly, the recombinant vectors were capable of controlling MO5 tumor growth. Indeed, the administration of MVAΔ008-OVA or MVA-OVA in prophylactic and therapeutic schemes provided total protection and longer survival of mice, respectively. Overall, our results demonstrate the improved immunogenicity and the protective capacity of MVAΔ008 against a heterologous model antigen. These findings suggest that MVAΔ008 constitutes an excellent candidate for vaccine development against pathogens or cancer therapy.

Synergistic cancer immunotherapy combines MVA-CD40L induced innate and adaptive immunity with tumor targeting antibodies

Virus-based vaccines and appropriate costimulation potently enhance antigen-specific T cell immunity against cancer. Here we report the use of recombinant modified vaccinia virus Ankara (rMVA) encoding costimulatory CD40L against solid tumors. Therapeutic treatment with rMVA-CD40L-expressing tumor-associated antigens results in the control of established tumors. The expansion of tumor-specific cytotoxic CD8⁺ T cells is essential for the therapeutic antitumor effects. Strikingly, rMVA-CD40L also induces strong natural killer (NK) cell activation and expansion. Moreover, the combination of rMVA-CD40L and tumor-targeting antibodies results in increased therapeutic antitumor efficacy relying on the presence of Fc receptor and NK cells. We describe a translationally relevant therapeutic synergy between systemic viral vaccination and CD40L costimulation. We show strengthened antitumor immune responses when both rMVA-CD40L-induced innate and adaptive immune mechanisms are exploited by combination with tumor-targeting antibodies. This immunotherapeutic approach could translate into clinical cancer therapies where tumor-targeting antibodies are employed.

CD40 agonists have been investigated as a strategy to awaken the immune system against cancers. Here, the authors use a virus encoding CD40L and tumour-associated antigens to enhance innate and adaptive immunity that together with tumour targeting antibodies controls the growth of tumours in mice.

Intratumoral injection of gels containing losartan microspheres and (PLG-g-mPEG)-cisplatin nanoparticles improves drug penetration, retention and anti-tumor activity

Intratumoral injection of chemotherapy agents may be employed in the treatment of cancers. However, its anti-tumor efficacy is significantly impeded by collagen fibers in the tumor which decrease drug penetration into the tumor tissues. To improve the penetration, collagen inhibiting drug exposure is required. In this study, microspheres were fabricated by the modified double emulsion-solvent evaporation method as the drug delivery system of losartan potassium (LP MSs), with 5% gelatin as the inner phase. The collagen inhibiting experiment analyzed by Sirius Red stains demonstrated that LP MSs may effectively inhibit collagen I synthesis in B16 tumors. In addition, 15% F127 was used as the solvent to fix the formulations at the injection site, with poly (α-l-glutamate) grafted polyethylene glycol mono methyl ether (PLG-g-mPEG)-cisplatin loaded nanoparticles (CDDP NPs) as the model drug. The in vivo live imaging system showed that formulations dissolved in 15% F127 had 54.91% CDDP NPs retained in tumors at the end of 10 days, in comparison with 19.72% for those solved in water, suggesting strong intratumoral retention property of the in situ gel. In addition, confocal laser scanning microscope (CLSM) and Energy-Dispersive Analysis of X-ray spectroscopy combined with scanning electron microscope (SEM-EDAX) tests showed that LP MSs can effectively enhance the distribution and penetration of CDDP NPs within tumors. Furthermore, tumors i.t. treated with LP MSs/CDDP NPs gel could be significantly halted, or even reduced to 200 mm³, comparing with a volume of about 12000 mm³ incontrol group at the end of the anti-tumor effect experiment. These results provided important guiding principles for prolonged and localized drug delivery system of intratumoral collagen inhibitor. The improvements of intratumoral penetration method made in this study provided practical significance for the treatment of cancer, especially for mass tumors.

CpG ODN1826 as a Promising Mucin1-Maltose-Binding Protein Vaccine Adjuvant Induced DC Maturation and Enhanced Antitumor Immunity

Mucin 1 (MUC1), being an oncogene, is an attractive target in tumor immunotherapy. Maltose binding protein (MBP) is a potent built-in adjuvant to enhance protein immunogenicity. Thus, a recombinant MUC1 and MBP antitumor vaccine (M-M) was constructed in our laboratory. To enhance the antitumor immune activity of M-M, CpG oligodeoxynucleotides 1826 (CpG 1826), a toll-like receptor-9 agonist, was examined in this study as an adjuvant. The combination of M-M and CpG 1826 significantly inhibited MUC1-expressing B16 cell growth and prolonged the survival of tumor-bearing mice. It induced MUC1-specific antibodies and Th1 immune responses, as well as the Cytotoxic T Lymphocytes (CTL) cytotoxicity in vivo. Further studies showed that it promoted the maturation and activation of the dendritic cell (DC) and skewed towards Th1 phenotype in vitro. Thus, our study revealed that CpG 1826 is an efficient adjuvant, laying a foundation for further M-M clinical research.

CD70 encoded by modified vaccinia virus Ankara enhances CD8 T-cell-dependent protective immunity in MHC class II-deficient mice

The immunological outcome of infections and vaccinations is largely determined during the initial first days in which antigen-presenting cells instruct T cells to expand and differentiate into effector and memory cells. Besides the essential stimulation of the T-cell receptor complex a plethora of co-stimulatory signals not only ensures a proper T-cell activation but also instils phenotypic and functional characteristics in the T cells appropriate to fight off the invading pathogen. The tumour necrosis factor receptor/ligand pair CD27/CD70 gained a lot of attention because of its key role in regulating T-cell activation, survival, differentiation and maintenance, especially in the course of viral infections and cancer. We sought to investigate the role of CD70 co-stimulation for immune responses induced by the vaccine vector modified vaccinia virus Ankara-Bavarian Nordic^® (MVA-BN^® ). Short-term blockade of CD70 diminished systemic CD8 T-cell effector and memory responses in mice. The dependence on CD70 became even more apparent in the lungs of MHC class II-deficient mice. Importantly, genetically encoded CD70 in MVA-BN^® not only increased CD8 T-cell responses in wild-type mice but also substituted for CD4 T-cell help. MHC class II-deficient mice that were immunized with recombinant MVA-CD70 were fully protected against a lethal virus infection, whereas MVA-BN^® -immunized mice failed to control the virus. These data are in line with CD70 playing an important role for vaccine-induced CD8 T-cell responses and prove the potency of integrating co-stimulatory molecules into the MVA-BN^® backbone.

Sequential administration of MVA-based vaccines and PD-1/PD-L1-blocking antibodies confers measurable benefits on tumor growth and survival: Preclinical studies with MVA-βGal and MVA-MUC1 (TG4010) in a murine tumor model

TG4010, a Modified Vaccinia virus Ankara (MVA) expressing human mucin1 (MUC1) has demonstrated clinical benefit for patients suffering from advanced non-small cell lung cancer (NSCLC) in combination with chemotherapy. To support its development, preclinical experiments were performed with either TG4010 or β-galactosidase-encoding MVA vector (MVA-βgal) in mice presenting tumors in the lung. Tumor growth was obtained after intravenous injection of CT26 murine colon cancer cells, engineered to express either MUC1 or βgal. Mice showed increased survival rates after repeated intravenous injections of TG4010 or MVA-βgal, compared to an empty MVA control vector. Treatment with MVA vectors led to the accumulation of CD3^dimCD8^dim T cells, with two subpopulations characterized as KLRG1⁺CD127⁻ short-lived effector cells (SLECs), and KLRG1⁻CD127⁻ early effector cells (EECs) comprising cells releasing IFNγ, Granzyme B and CD107a upon antigen-specific peptide stimulation. EECs were characterized by an up-regulation of PD-1. Tumor growth in the diseased lung correlated with the appearance of PD1⁺ Treg cells that partially disappeared after TG4010 treatment. At late stage of tumor development in the lung, PD-L1 was detected on CD45⁻ tumor cells, on CD4⁺ cells, including Treg cells, on CD3⁺CD8⁺ and CD3^dimCD8^dim T lymphocytes, on NK cells, on MDSCs and on alveolar macrophages. We demonstrated that targeting the PD-1/PD-L1 pathway with blocking monoclonal antibodies several days after TG4010 treatment, at late stage of tumor development, enhanced the therapeutic protection induced by the vaccine, supporting the ongoing clinical evaluation of TG4010 immunotherapy in combination with Nivolumab.

Viral based vaccine TG4010 induces broadening of specific immune response and improves outcome in advanced NSCLC

BACKGROUND

Advanced non-small cell lung cancer patients receiving TG4010, a therapeutic viral vaccine encoding human Mucin 1 and interleukin-2 in addition to standard chemotherapy, displayed longer overall survival in comparison to that of patients treated with standard chemotherapy alone. Our study intended to establish the association between overall survival and vaccine-induced T cell responses against tumor associated antigens (TAA) targeted by the vaccine.

METHOD

The TIME trial was a placebo-controlled, randomized phase II study aimed at assessing efficacy of TG4010 with chemotherapy in NSCLC. 78 patients from the TIME study carrying the HLA-A02*01 haplotype were analyzed using combinatorial encoding of MHC multimers to detect low frequencies of cellular immune responses to TG4010 and other unrelated TAA.

RESULTS

We report that improvement of survival under TG4010 treatment correlated with development of T cell responses against MUC1. Interestingly, responses against MUC1 were associated with broadening of CD8 responses against non-targeted TAA, thus demonstrating induction of epitope spreading.

CONCLUSION

Our results support the causality of specific T-cell response in improved survival in NSCLC. Additionally, vaccine induced epitope spreading to other TAA participates to the enrichment of the diversity of the anti-tumor response. Hence, TG4010 appears as a useful therapeutic option to maximize response rate and clinical benefit in association with other targeted immuno-modulators.

TRIAL REGISTRATION

Registered on ClinicalTrials.gov under identifier NCT01383148 on June 23rd, 2011.

Sequential administration of a MVA-based MUC1 cancer vaccine and the TLR9 ligand Litenimod (Li28) improves local immune defense against tumors

TG4010 is an immunotherapeutic vaccine based on Modified Vaccinia virus Ankara (MVA) encoding the human tumor-associated antigen MUC1 and human IL-2. In combination with first-line standard of care chemotherapy in advanced metastatic non-small-cell lung cancer (NSCLC), repeated subcutaneous injection of TG4010 improved progression-free survival in phase 2b clinical trials. In preclinical tumor models, MVATG9931, the research version of TG4010, conferred antigen-specific responses against the weak antigen human MUC1. The combination of a suboptimal dose of MVATG9931 and the type B TLR9 ligand Litenimod (Li28) markedly increased survival in a subcutaneous RMA-MUC1 tumor model compared to the treatment with MVATG9931 or Li28 alone. The requirements for this protection were (i) de novo synthesis of MUC1, (ii) Li28 delivered several hours after MVATG9931 at the same site, (iii) at least two vaccination cycles, and (iv) implantation of MUC1-positive tumor cells in the vicinity to the vaccination site. Subcutaneously injected MVATG9931 allowed transient local gene expression and induced the local accumulation of MCP-1, RANTES, M-CSF, IL-15/IL-15R and IP-10. After repeated injection, CD4⁺ and CD8⁺ T lymphocytes, B lymphocytes, NK cells, pDCs, neutrophils, and macrophages accumulated around the injection site, local RANTES levels remained high. Delayed injection of Li28 into this environment, led to further accumulation of macrophages, the secretion of IL-18 and IL-1 beta, and an increase of the percentage of activated CD69⁺ NK cell. Combination treatment augmented the number of activated CD86⁺ DCs in the draining lymph nodes and increased the percentage of KLRG1⁺ CD127^-CD8⁺ T cells at the injection site. In vivo depletion of macrophages around the injection site by Clodronate liposomes reduced local IL-18 levels and diminished survival rates significantly. Thus, sequential administration of MVATG9931 and Li28 improves local innate and adaptive immune defense against tumors, arguing for intratumoral delivery of this peculiar sequential combination therapy.

Shaping the tumor microenvironment with Modified Vaccinia Virus Ankara and TLR9 ligand

Our preclinical data demonstrate that an intravenous injection of Modified Vaccinia virus Ankara induces CD8⁺ lymphocytes to infiltrate organs to control the growth of orthotopic renal carcinoma upon combination with a toll-like receptor 9 agonist. Such shaping of the tumor microenvironment could constitute the basis of more effective clinical protocols of tumor immunotherapy.