Tumor Lysate-loaded Dendritic Cells Research Articles

Enhancement of antitumor immunity by combining anti-cytotoxic T lymphocyte antigen-4 antibodies and cryotreated tumor lysate-pulsed dendritic cells in murine osteosarcoma

Immunotherapy with tumor lysate-loaded dendritic cells (DCs) is one of the most promising strategies to induce antitumor immune responses. However, the antitumor activity of cytotoxic Tcells may be restrained by their expression of the inhibitory T-cell coreceptor cytotoxic Tlymphocyte antigen-4 (CTLA-4). By relieving this restraint, CTLA-4-blocking antibodies promote tumor rejection, but the full scope of their most suitable applications has yet to be fully determined. In the present study, we offer proof of a preclinical concept in a C3Hmouse osteosarcoma (LM8) model that CTLA-4 blockade cooperates with cryotreated tumor lysate-pulsed DCs in a primary tumor to prevent the outgrowth of lung metastasis. To evaluate immune response activation, we established the following four groups of C3Hmice (60mice in total): i)control immunoglobulinG (IgG)-treated mice; ii)tumor lysate-pulsed DC-treated mice; iii)anti-CTLA-4 antibody-treated mice and iv)tumor lysate-pulsed DC- and anti-CTLA-4 antibody-treated mice. The mice that received the tumor lysate-pulsed DCs and anti-CTLA-4 antibody displayed reduced numbers of regulatory Tlymphocytes and increased numbers of CD8+Tlymphocytes inside the metastatic tumor, inhibition of metastatic growth, a prolonged lifetime, reduced numbers of regulatory Tlymphocytes in the spleen and high serum interferon-γ levels. Combining an anti-CTLA-4 antibody with tumor lysate-pulsed DCs enhanced the systemic immune response. To the best of our knowledge, these findings document for the first time an effect of the combination of tumor lysate-pulsed DCs and CTLA-4-blocking antibodies in osteosarcoma. We suggest that cryotreated tumor lysate-pulsed DCs, although insufficient on their own, may mediate the rejection of metastatic lesions and prevent recurrence of the disease when combined with CTLA-4 blockade in osteosarcoma patients in the clinical setting.

Immune Response in Patients With Newly Diagnosed Glioblastoma Multiforme Treated With Intranodal Autologous Tumor Lysate-dendritic Cell Vaccination After Radiation Chemotherapy

Patients with glioblastoma multiforme (GBM) are profoundly immunosuppressed and may benefit from restoration of an antitumor immune response in combination with conventional radiation therapy and temozolomide (TMZ). The optimal strategies to evaluate clinically relevant immune responses to treatment have yet to be determined. The primary objective of our study was to determine immunologic response to cervical intranodal vaccination with autologous tumor lysate-loaded dendritic cells (DCs) in patients with GBM after radiation therapy and TMZ. We used a novel hierarchical clustering analysis of immune parameters measured before and after vaccination. Secondary objectives were to assess treatment feasibility and to correlate immune response with progression-free survival (PFS) and overall survival. Ten eligible patients received vaccination. Tumor-specific cytotoxic T-cell response measured after vaccination was enhanced for the precursor frequency of CD4+ T and CD4+ interferon γ-producing cells. Hierarchical clustering analysis of multiple functional outcomes discerned 2 groups of patients according to their immune response, and additionally showed that patients in the top quintile for at least one immune function parameter had improved survival. There were no serious adverse events related to DC vaccination. All patients were alive at 6 months after diagnosis and the 6-month PFS was 90%. The median PFS was 9.5 months and overall survival was 28 months. In patients with GBM, immune therapy with DC vaccination after radiation and TMZ resulted in tumor-specific immune responses that were associated with prolonged survival. Our data suggest that DC vaccination in combination with radiation and chemotherapy in patients with GBM is feasible, safe, and may induce tumor-specific immune responses.

The TLR7 agonists imiquimod and gardiquimod improve DC-based immunotherapy for melanoma in mice

Toll-like receptors (TLRs) are a family of highly conserved germline-encoded pattern-recognition receptors that are essential for host immune responses. TLR ligands represent a promising class of immunotherapeutics or vaccine adjuvants with the potential to generate an effective antitumor immune response. The TLR7/8 agonists have aroused interest because they not only activate antigen-presenting cells but also promote activation of T and natural killer (NK) cells. However, the exact mechanism by which stimulation of these TLRs promotes immune responses remains unclear, and different TLR7/8 agonists have been found to induce different responses. In this study, we demonstrate that both gardiquimod and imiquimod promote the proliferation of murine splenocytes, stimulate the activation of splenic T, NK and natural killer T (NKT) cells, increase the cytolytic activity of splenocytes against B16 and MCA-38 tumor cell lines, and enhance the expression of costimulatory molecules and IL-12 by macrophages and bone marrow-derived dendritic cells (DCs). In a murine model, both agonists improved the antitumor effects of tumor lysate-loaded DCs, resulting in delayed growth of subcutaneous B16 melanoma tumors and suppression of pulmonary metastasis. Further, we found that gardiquimod demonstrated more potent antitumor activity than imiquimod. These results suggest that TLR7/8 agonists may serve as potent innate and adaptive immune response modifiers in tumor therapy. More importantly, they can be used as vaccine adjuvants to potentiate the efficiency of DC-based tumor immunotherapy.

Induction of tumor-specific T-cell responses by vaccination with tumor lysate-loaded dendritic cells in colorectal cancer patients with carcinoembryonic-antigen positive tumors

Induction of tumor-specific T-cell responses by vaccination with tumor lysate-loaded dendritic cells in colorectal cancer patients with carcinoembryonic-antigen positive tumors

503: Intranodal Tumor Lysate-Loaded Dendritic Cell Vaccine, Combined with Interleukin-2 and Interferon-A, In Patients with Metastatic Renal Cell Carcinoma - Exciting Clinical Results and Immunologic Data

503: Intranodal Tumor Lysate-Loaded Dendritic Cell Vaccine, Combined with Interleukin-2 and Interferon-A, In Patients with Metastatic Renal Cell Carcinoma - Exciting Clinical Results and Immunologic Data

Persistent IL-10 production is required for glioma growth suppressive activity by Th1-directed effector cells after stimulation with tumor lysate-loaded dendritic cells

Injection of dendritic cells (DC) pulsed with tumor antigens is a novel treatment strategy against malignancies, and aims to elicit anti-tumoral cell-mediated immune responses. We studied the in vitro proliferative responses and cytokine production in T cell cultures after 2 stimulations with autologous DC loaded with tumor lysates derived from glioblastoma multiforme (GBM) cells in the presence of recombinant interleukin (rIL)-6/rIL-12 in the first, and rIL-2/rIL-7 in the second stimulation. After the second stimulation, T cells were co-cultured with glioblastoma (GBM) cells and tumor growth suppression by T cells was assessed using a MTT assay. Although loaded DC induced a significant shift towards T helper cell type 1 (Th1) cytokine production as compared to unloaded DC, persistent interleukin (IL)-10 production by T cells both at the end of 2 stimulations with loaded DC and during the effector phase was also required for their tumor suppressive activity. A stronger glioma growth suppressive activity by T cells stimulated with tumor lysate-loaded DC than by control T cells, cultured with unloaded DC, was seen only if the relative IL-10 production after two stimulations with loaded DC was at least 40% of the IL-10 production after two stimulations with unloaded DC. If less than 40% IL-10 was produced in the experimental condition compared to the control condition, T cells also lost their tumor growth suppressive activity. Addition of rIL-10 during stimulation increased the suppressive activity on tumor cell viability and interferon (IFN)-gamma production by T cells that showed Th1 response upon stimulation with loaded DC. The data point towards the production of both IFN-gamma and IL-10 by responding effector T cells, and towards an immune modulatory rather than immune suppressive role of IL-10 to generate anti-tumoral effector T cells against GBM.

Induction of tumor-specific T-cell responses by vaccination with tumor lysate-loaded dendritic cells in colorectal cancer patients with carcinoembryonic-antigen positive tumors.

Dendritic cells (DCs) are the most effective antigen-presenting cells. In the last decade, the use of DCs for immunotherapy of cancer patients has been vastly increased. High endocytic capacity together with a unique capability of initiating primary T-cell responses have made DCs the most potent candidates for this purpose. Although DC vaccination occasionally leads to tumor regression, clinical efficacy, and immunogenicity of DCs in clinical trials has not been yet clarified. The present study evaluated the safety and effectiveness of tumor-lysate loaded DC vaccines in advanced colorectal cancer (CRC) patients with carcinoembryonic antigen (CEA) positive tumors. Six patients HLA-A*0201-positive were vaccinated with autologous DCs loaded with tumor lysates (TL) together with tetanus toxoid antigen, hepatitis B, and influenza matrix peptides. Two additional patients were injected with DCs that were generated from their sibling or parent with one haplotype mismatch. All patients received the vaccines every 2 weeks, with a total of three intra-nodal injections per patient. The results indicated that DC vaccination was safe and well tolerated by the patients. Specific immune responses were detected and in some patients, transient stabilization or even reduction of CEA levels were observed. The injection of haplotype mismatched HLA-A*0201-positive DCs resulted in some enhancement of the anti-tumor response in vitro and led to stabilization/reduction of CEA levels in the serum, compared to the use of autologous DCs. Altogether, these results suggest that TL-pulsed DCs may be an effective vaccine method in CRC patients. Elimination of regulatory mechanisms as well as adjustment of the vaccination protocol may improve the efficacy of DC vaccination.

Double loading of dendritic cell MHC class I and MHC class II with an AML antigen repertoire enhances correlates of T-cell immunity in vitro via amplification of T-cell help

Therapeutic vaccination with dendritic cells presenting tumor-specific antigens is now recognized as an important investigational therapy for the treatment of neoplastic disease. Dendritic cell cross-presentation is credited with the ability of tumor lysate-loaded dendritic cells to prime both CD4 and CD8-specific T-lymphocyte responses, enabling the generation of cancer specific CTL activity without the loading of the classical MHC class I compartment. Recently, however, several reports have raised doubts as to the efficiency of cross-presentation as a mechanism for CTL priming in vivo. To examine this issue, we have doubly-loaded human dendritic cells with both AML-specific tumor lysate and AML-specific tumor mRNA. Our results show that these doubly-loaded dendritic cells can mediate superior primary, recall, and effector lytic responses in vitro in comparison to those of dendritic cells loaded with either tumor lysate or tumor mRNA alone. Enhanced recall responses appeared to be influenced by CD40/CD40L signaling, underscoring the importance of T-cell help in the generation and perpetuation of the adaptive immune response.

Optimization of Immune Monitoring Protocols to Amplify and Detect Antigen-specific T Cells Insuced by Vaccination With Tumor Lysate-Loaded Dendritic Cells

s: Abstracts for the 20th Annual Scientific Meeting of the International Society for Biological Therapy of Cancer (Primary Authors are Italicized): IMMUNE MONITORING

Tumor lysate and IL-18 loaded dendritic cells elicits Th1 response, tumor-specific CD8+ cytotoxic T cells in patients with malignant glioma

In this study, we demonstrate that tumor lysate-loaded dendritic cells can elicit a specific CD8+ cytotoxic T lymphocyte response against autologous tumor cells in patients with malignant glioma. CTL from three of five patients expressed strong cytolytic activity against autologous glioma cells, did not lyse autologous lymphoblasts and were variably cytotoxic against the LAK-sensitive cell line Daudi. Also, DCs pulsed normal brain lysate failed to induce cytolytic activity against autologous glioma cells, suggesting the lack of autoimmune response. Two of five patients CD8+ T cells expressed a modest cytotoxicity against autologous glioma cells. CD8+ T cells isolated during these ineffective primings secreted large amounts of IL-10, less amounts of IFN-gamma as detected by ELISA, Type 2 bias in the CD8+ T cell response accounts for the lack of cytotoxic effector function from these patients. Cytotoxicity against autologous glioma cells could be significantly inhibited by anti-HLA class I antibody. These data demonstrate that tumor lysate-loaded DC can be an effective tool in inducing glioma-specific CD8+ CTL able to kill autologous glioma cells in vitro. However, high levels of tumor specific tolerance in some patients may account for a significant barrier to therapeutic vaccination. Moreover, cytotoxic responses were augmented by transfecting DC with the gene for IL-18. For all five patients, CD8+T cells treated with IL18 transfected DC produced Th1 response. These results may have important implications for the treatment of malignant glioma patients with immunotherapy. DCs loaded with total tumor lysate and IL-18 may represent a method for inducing Th1 immunoresponses against the entire repertoire of glioma antigens.

Tumour lysate-loaded dendritic cells are well tolerated in patients with metastatic renal cell cancer,

Tumour lysate-loaded dendritic cells are well tolerated in patients with metastatic renal cell cancer,