Immunotherapeutic Approaches (immunotherapeutic + approach)

Distribution by Scientific Domains


Selected Abstracts


Strategies and challenges in eliciting immunity to melanoma

IMMUNOLOGICAL REVIEWS, Issue 1 2008
Andrew R. Ferguson
Summary: The ability of CD8+ T cells to recognize melanoma tumors has led to the development of immunotherapeutic approaches that use the antigens CD8+ T cells recognize. However, clinical response rates have been disappointing. Here we summarize our work to understand the mechanisms of self-tolerance that limit responses to currently utilized antigens and our approach to identify new antigens directly tied to malignancy. We also explore several aspects of the anti-tumor immune response induced by peptide-pulsed dendritic cells (DCs). DCs differentially augment the avidity of recall T cells specific for self-antigens and overcome a process of aberrant CD8+ T-cell differentiation that occurs in tumor-draining lymph nodes. DC migration is constrained by injection route, resulting in immune responses in localized lymphoid tissue, and differential control of tumors depending on their location in the body. We demonstrate that CD8+ T-cell differentiation in different lymphoid compartments alters the expression of homing receptor molecules and leads to the presence of systemic central memory cells. Our studies highlight several issues that must be addressed to improve the efficacy of tumor immunotherapy. [source]


Targeted therapy of renal cell carcinoma: Synergistic activity of cG250-TNF and IFNg

INTERNATIONAL JOURNAL OF CANCER, Issue 1 2009
Stefan Bauer
Abstract Immunotherapeutic targeting of G250/Carbonic anhydrase IX (CA-IX) represents a promising strategy for treatment of renal cell carcinoma (RCC). The well characterized human-mouse chimeric G250 (cG250) antibody has been shown in human studies to specifically enrich in CA-IX positive tumors and was chosen as a carrier for site specific delivery of TNF in form of our IgG-TNF-fusion protein (cG250-TNF) to RCC xenografts. Genetically engineered TNF constructs were designed as CH2/CH3 truncated cG250-TNF fusion proteins and eucariotic expression was optimized under serum-free conditions. In-vitro characterization of cG250-TNF comprised biochemical analysis and bioactivity assays, alone and in combination with Interferon-, (IFN,). Biodistribution data on radiolabeled [125J] cG250-TNF and antitumor activity of cG250-TNF, alone and in combination with IFN,, were measured on RCC xenografts in BALB/c nu/nu mice. Combined administration of cG250-TNF and IFN, caused synergistic biological effects that represent key mechanisms displaying antitumor responses. Biodistribution studies demonstrated specific accumulation and retention of cG250-TNF at CA-IX-positive RCC resulting in growth inhibition of RCC and improved progression free survival and overall survival. Antitumor activity induced by targeted TNF-based constructs could be enhanced by coadministration of low doses of nontargeted IFN, without significant increase in side effects. Administration of cG250-TNF and IFN, resulted in significant synergistic tumoricidal activity. Considering the poor outcome of renal cancer patients with advanced disease, cG250-TNF-based immunotherapeutic approaches warrant clinical evaluation. © 2009 UICC [source]


IFN-, withdrawal after immunotherapy potentiates B16 melanoma invasion and metastasis by intensifying tumor integrin ,v,3 signaling

INTERNATIONAL JOURNAL OF CANCER, Issue 3 2008
Wei Gong
Abstract Immunotherapy can effectively suppress tumor, yet complete tumor eradication occurs infrequently. The metastatic potential of remnant tumor cells after immunotherapy and the underlying mechanisms have not been fully elucidated. Here, we report that the termination of immunotherapy strikingly increases the metastatic potential of remnant melanoma. This is mainly due to the withdrawal of IFN-, after immunotherapy. The relief of IFN-, stress led to the increase of ,v,3 integrin expression in B16 cells, which increased the adhesion of B16 cells to fibrinogen, fibronectin and laminin. Through ,v,3 signaling, the activation of FAK, upregulation of cdc2, production of active MMP-2 and MMP-9 and actin polymerization were intensified in B16 cells stimulated with ECM molecules 24 h after the withdrawal of IFN-,. The i.v. injection of such tumor cells into mice resulted in more metastatic tumor nodes in lung and shortened the survival of mice. The pitfall of immunotherapy termination can be remedied by the administration of recombinant CBD-HepII polypeptide of fibronectin, which effectively inhibits ,v,3 signaling. These findings suggest that the risk of tumor metastasis can be increased after the termination of immunotherapy, due to the withdrawal of IFN-, and that targeting ,v,3 signaling pathway can improve the therapeutic effect of immunotherapeutic approaches by reducing such metastatic risk. © 2008 Wiley-Liss, Inc. [source]


Natural killer cell-based immunotherapy in cancer: current insights and future prospects

JOURNAL OF INTERNAL MEDICINE, Issue 2 2009
T. Sutlu
Abstract. As our understanding of the molecular mechanisms governing natural killer (NK) cell activity increases, their potential in cancer immunotherapy is growing increasingly prominent. This review analyses the currently available preclinical and clinical data regarding NK cell-based immunotherapeutic approaches in cancer starting from a historical background and an overview of molecular mechanisms taking part in NK cell responses. The status of NK cells in cancer patients, currently investigated clinical applications such as in vivo modulation of NK cell activity, ex vivo purification/expansion and adoptive transfer as well as future possibilities such as genetic modifications are discussed in detail. [source]


Dendritic cells lentivirally engineered to overexpress interleukin-10 inhibit contact hypersensitivity responses, despite their partial activation induced by transduction-associated physical stress

THE JOURNAL OF GENE MEDICINE, Issue 3 2010
Verena Besche
Abstract Background Dendritic cells (DCs) constitute an attractive target for immunotherapeutic approaches. Because DCs are largely refractory to transfection with plasmid DNA, several viral transduction protocols were established. The potential side-effects of lentiviral transduction on the phenotype and activation state of DCs left unstimulated after transduction have not been assessed. There is a need to analyse these parameters as a result of the requirement of using DCs with a low activation state for therapeutic strategies intended to induce tolerance. Methods Lentivirally-transduced bone marrow (BM)-derived DCs (LV-DCs) in comparison with mock-transduced (Mock-DCs) and untreated DCs were analysed with regard to the induction of maturation processes on the RNA, protein and functional level. BM-DCs engineered to overexpress interleukin (IL)-10 were analysed for therapeutic potential in a mouse model of allergic contact dermatitis. Results Compared with untreated DCs, Mock-DCs and LV-DCs displayed an altered gene expression signature. Mock-DCs induced a stronger T cell proliferative response than untreated DCs. LV-DCs did not further augment the T cell proliferative response, but induced a slightly different T cell cytokine pattern compared to Mock-DCs. Accordingly, the gene promoter of the DC maturation marker fascin mediated efficient expression of the model transgene IL-10 in unstimulated-transduced BM-DCs. Nevertheless, IL-10 overexpressing BM-DCs exerted tolerogenic activity and efficiently inhibited the contact hypersensitivity response in previously hapten-sensitized mice. Conclusions Lentiviral transduction of BM-DCs results in their partial activation. Nevertheless, the transduction of these DCs with a vector encoding the immunomodulatory cytokine IL-10 rendered them tolerogenic. Thus, lentivirally-transduced DCs expressing immunomodulatory molecules represent a promising tool for induction of tolerance. Copyright © 2010 John Wiley & Sons, Ltd. [source]


Tolerization with Hsp65 induces protection against adjuvant-induced arthritis by modulating the antigen-directed interferon-,, interleukin-17, and antibody responses

ARTHRITIS & RHEUMATISM, Issue 1 2009
Shailesh R. Satpute
Objective Pretreatment of Lewis rats with soluble mycobacterial Hsp65 affords protection against subsequent adjuvant-induced arthritis (AIA). This study was aimed at unraveling the mechanisms underlying mycobacterial Hsp65,induced protection against arthritis, using contemporary parameters of immunity. Methods Lewis rats were given 3 intraperitoneal injections of mycobacterial Hsp65 in solution prior to the initiation of AIA with heat-killed Mycobacterium tuberculosis. Thereafter, mycobacterial Hsp65,specific T cell proliferative, cytokine, and antibody responses were tested in tolerized rats. The roles of anergy and the indoleamine 2,3 dioxygenase (IDO),tryptophan pathway in tolerance induction were assessed, and the frequency and suppressive function of CD4+FoxP3+ Treg cells were monitored. Also tested was the effect of mycobacterial Hsp65 tolerization on T cell responses to AIA-related mycobacterial Hsp70, mycobacterial Hsp10, and rat Hsp65. Results The AIA-protective effect of mycobacterial Hsp65,induced tolerance was associated with a significantly reduced T cell proliferative response to mycobacterial Hsp65, which was reversed by interleukin-2 (IL-2), indicating anergy induction. The production of interferon-, (but not IL-4/IL-10) was increased, with concurrent down-regulation of IL-17 expression by mycobacterial Hsp65,primed T cells. Neither the frequency nor the suppressive activity of CD4+FoxP3+ T cells changed following tolerization, but the serum level of anti,mycobacterial Hsp65 antibodies was increased. However, no evidence was observed for a role of IDO or cross-tolerance to mycobacterial Hsp70, mycobacterial Hsp10, or rat Hsp65. Conclusion Tolerization with soluble mycobacterial Hsp65 leads to suppression of IL-17, anergy induction, and enhanced production of anti,mycobacterial Hsp65 antibodies, which play a role in protection against AIA. These results are relevant to the development of effective immunotherapeutic approaches for autoimmune arthritis. [source]


The immunotherapeutic potential of dendritic cells in type 1 diabetes

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 2 2010
G. Mukherjee
Summary Type 1 diabetes is an autoimmune disease characterized by destruction of the pancreatic islet beta cells that is mediated primarily by T cells specific for beta cell antigens. Insulin administration prolongs the life of affected individuals, but often fails to prevent the serious complications that decrease quality of life and result in significant morbidity and mortality. Thus, new strategies for the prevention and treatment of this disease are warranted. Given the important role of dendritic cells (DCs) in the establishment of peripheral T cell tolerance, DC-based strategies are a rational and exciting avenue of exploration. DCs employ a diverse arsenal to maintain tolerance, including the induction of T cell deletion or anergy and the generation and expansion of regulatory T cell populations. Here we review DC-based immunotherapeutic approaches to type 1 diabetes, most of which have been employed in non-obese diabetic (NOD) mice or other murine models of the disease. These strategies include administration of in vitro -generated DCs, deliberate exposure of DCs to antigens before transfer and the targeting of antigens to DCs in vivo. Although remarkable results have often been obtained in these model systems, the challenge now is to translate DC-based immunotherapeutic strategies to humans, while at the same time minimizing the potential for global immunosuppression or exacerbation of autoimmune responses. In this review, we have devoted considerable attention to antigen-specific DC-based approaches, as results from murine models suggest that they have the potential to result in regulatory T cell populations capable of both preventing and reversing type 1 diabetes. [source]


Translational Mini-Review Series on Vaccines: Dendritic cell-based vaccines in renal cancer

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2007
E. Ranieri
Summary Renal cancer is a relatively uncommon solid tumor, accounting for about 3% of all adult malignancies, however this rate incidence is rising. The most common histological renal cell carcinoma (RCC) subtype is clear cell carcinoma that makes up approximately 70,80% of all renal neoplasms and appears to be the only histological subtype that is responsive to immunotherapeutic approaches with any consistency. Therefore, it has been hypothesized that immune-mediated mechanisms play important roles in limiting tumor growth and that dendritic cells (DC), the most potent APC in the body, and T cells are the dominant effector cells that regulate tumor progression in situ. In this context, the development of clinically effective DC-based vaccines is a major focus for active specific immunotherapy in renal cancer. In the current review we have not focused on the results of recently published RCC clinical trials, as several excellent reviews have already performed this function. Instead, we turned our attention to how the perception and practical application of DC-based vaccinations are evolving. [source]