Breast cancer immunotherapy

Breast cancer is a leading cause of cancer-related deaths in women worldwide.Although tumorectomy,radiotherapy,chemotherapy and hormone replacement therapy have been used for the treatment of breastcancer,there is no effective therapy for patients with invasive and metastatic breast cancer.Immunotherapymay be proved effective in treating patients with advanced breast cancer.Breast cancer immunotherapyincludes antibody based immunotherapy,cancer vaccine immunotherapy,adoptive T cell transferimmunotherapy and T cell receptor gene transfer immunotherapy.Antibody based immunotherapy such as themonoclonal antibody against HER-2/neu (trastuzumab) is successfully used in the treatment of breast cancerpatients with over-expressed HER-2/neu,however,HER-2/neu is over-expressed only in 25-30% of breastcancer patients.Cancer vaccine immunotherapy is a promising method to treat cancer patients.Cancervaccines can be used to induce specific anti-tumor immunity in breast cancer patients,but cannot induceobjective tumor regression.Adoptive T cell transfer immunotherapy is an effective method in the treatment ofmelanoma patients.Recent advances in anti-tumor T cell generation ex vivo and limited clinical trial data havemade the feasibility of adoptive T cell transfer immunotherapy in the treatment of breast cancer patients.T cellreceptor gene transfer can redirect the specificity of T cells.Chimeric receptor,scFv(anti-HER-2/neu)/zetareceptor,was successfully used to redirect cytotoxic T lymphocyte hybridoma cells to obtain anti-HER-2/neupositive tumor cells,suggesting the feasibility of treatment of breast cancer patients with T cell receptor genetransfer immunotherapy.Clinical trials will approve that immunotherapy is an effective method to cure breastcancer disease in the near future.Cellular & Molecular Immunology.2004;1(4):247-255.     

T cell vaccination as an immunotherapy for autoimmune diseases

Immunization with inactivated autoreactive T cells(T cell vaccination) selected from individual's own T cellrepertoire provides a unique in vivo setting for testing immune regulation that is known to involve interactionsof a variety of related surface molecules(1).It induces regulatory immune responses that closely resemble thein vivo situation where the immune system is challenged by clonal activation and expansion of given T cellpopulations in various autoimmune diseases.T cell vaccination provides a powerful means of eliciting naturalreactions of the immune system in response to clonal expansion of T cells,which can be used as a therapeuticapproach to suppress or eliminate specific pathogenic autoreactive T cells in autoimmune conditions.Clinicaltrials using T cell vaccination to deplete autoreactive T cells in human autoimmune conditions have begun toreveal the pathologic relevance of various autoimmune T cell populations in the disease processes,providing aunique opportunity to test the autoimmune theories in a clinical setting.Cellular & Molecular Immunology.2004;1(5):321-327.     

Twelve immunotherapy drugs that could cure cancers

Summary: Immune T cells can kill cancer cells. Cancer vaccines function by increasing the number of immune T cells. There are exceedingly strict biologic limits imposed on the immune system to prevent excessive T-cell activation and expansion. The same biological restrictions limit cancer vaccines. Immunotherapeutic agents that circumvent the biological restrictions have been invented and formulated, including (i) dendritic cell activators and growth factors, (ii) vaccine adjuvants, (iii) T-cell stimulators and growth factors, (iv) immune checkpoint inhibitors, and (v) agents to neutralize or inhibit suppressive cells, cytokines, and enzymes. Few of these agents are broadly available for the development of effective multiple component regimens. The major problem facing immunotherapy today is a lack of broad availability of agents already in existence. The National Cancer Institute has developed a well-vetted ranked list of agents with high potential to serve as immunotherapeutic drugs. This review focuses on 12 of the agents, all with proven ability to augment T-cell responses. Alone, each has little chance of making substantial inroads into cancer therapy. In combinations dictated by biology, the agents are overwhelmingly likely to have an impact. Future availability of these agents for development of innovative combination cancer therapy regimens will provide a benchmark for the resolve of the national cancer therapy translational research enterprise.     

T cell receptor binding affinity governs the functional profile of cancer-specific CD8+ T cells

Antigen-specific T cell receptor (TCR) gene transfer via patient-derived T cells is an attractive approach to cancer therapy, with the potential to circumvent immune regulatory networks. However, high-affinity tumour-specific TCR clonotypes are typically deleted from the available repertoire during thymic selection because the vast majority of targeted epitopes are derived from autologous proteins. This process places intrinsic constraints on the efficacy of T cell-based cancer vaccines and therapeutic strategies that employ naturally generated tumour-specific TCRs. In this study, we used altered peptide ligands and lentivirus-mediated transduction of affinity-enhanced TCRs selected by phage display to study the functional properties of CD8⁺ T cells specific for three different tumour-associated peptide antigens across a range of binding parameters. The key findings were: (i) TCR affinity controls T cell antigen sensitivity and polyfunctionality; (ii) supraphysiological affinity thresholds exist, above which T cell function cannot be improved; and (iii) T cells transduced with very high-affinity TCRs exhibit cross-reactivity with self-derived peptides presented by the restricting human leucocyte antigen. Optimal system-defined affinity windows above the range established for natural tumour-specific TCRs therefore allow the enhancement of T cell effector function without off-target effects. These findings have major implications for the rational design of novel TCR-based biologics underpinned by rigorous preclinical evaluation.     

Acute myeloid leukaemia cells secrete a soluble factor that inhibits T and NK cell proliferation but not cytolytic function--implications for the adoptive immunotherapy of leukaemia.

Evidence of an immune mediated graft-versus-leukaemia effect has led to the belief that T and NK cell based adoptive immunotherapy can constitute effective treatment for relapsed leukaemias. However, work on solid tumours has shown this strategy may be hampered, by an immune escape mechanism in which tumour secreted immunosuppressive factors compromise T and NK cell function. Indeed, acute myeloid leukaemia (AML) cells secrete immunosuppressive factors that block the synthesis of Th1 type cytokines in T cells. We demonstrate here that this immunosuppression, mediated by both HL60 AML cell line and primary AML blasts, inhibits T and NK cell proliferation but not cytolytic activity. Supernatants from HL60 cell line and primary AML blasts inhibited T cell proliferation to mitogenic and alloantigen stimulation but had no effect on cytolytic function. Similarly, the proliferation of NK cells to IL-2 and IL-15 stimulation was inhibited whilst their cytolytic function, shown by lysis of AML blasts, K562 and Daudi cells remained unaffected. The failure of T and NK cells to proliferate was not due to effector cell apoptosis. Indeed, removal of lymphocytes from the immunosuppressive environment partially restored their capacity to respond to mitogenic stimulation. T cells exposed to immunosuppressive supernatants did not increase expression of mitotic inhibitory proteins that arrest cell division, thereby ruling this out as a mechanism of operation for this immunosuppression. T cell expansion requires antigen stimulation, usually provided in the form of AML blasts, therefore our data suggest that NK cells may be more practical for the immunotherapy of AML.     

T细胞受体基因转染过继性免疫治疗的研究进展

利用T细胞进行过继性免疫治疗是治疗病毒感染性疾病和肿瘤的理想方法,但是用于治疗的T细胞的特异性、亲和性和数量等限制了其应用,如何获得特异、高效、一定数量的T细胞是目前亟待解决的问题。采用TCR基因转染的方法,将特异性高亲和力TCR转移到受体的T细胞中,可以特异性杀伤受体体内的肿瘤细胞。     

Soluble and membrane‐bound interleukin (IL)‐15 Rα/IL‐15 complexes mediate proliferation of high‐avidity central memory CD8+ T cells for adoptive immunotherapy of cancer and infections

The lack of persistence of infused T cells is a principal limitation of adoptive immunotherapy in man. Interleukin (IL)‐15 can sustain memory T cell expansion when presented in complex with IL‐15Rα (15Rα/15). We developed a novel in‐vitro system for generation of stable 15Rα/15 complexes. Immunologically quantifiable amounts of IL‐15 were obtained when both IL‐15Rα and IL‐15 genes were co‐transduced in NIH 3T3 fibroblast‐based artificial antigen‐presenting cells expressing human leucocyte antigen (HLA) A:0201, β₂ microglobulin, CD80, CD58 and CD54 [A2‐artificial antigen presenting cell (AAPC)] and a murine pro‐B cell line (Baf‐3) (A2‐AAPC^15Rα/15and Baf‐3^15Rα/15). Transduction of cells with IL‐15 alone resulted in only transient expression of IL‐15, with minimal amounts of immunologically detectable IL‐15. In comparison, cells transduced with IL‐15Rα alone (A2‐AAPC^Rα) demonstrated stable expression of IL‐15Rα; however, when loaded with soluble IL‐15 (sIL‐15), these cells sequestered 15Rα/15 intracellularly and also demonstrated minimal amounts of IL‐15. Human T cells stimulated in vitro against a viral antigen (CMVpp65) in the presence of 15Rα/15 generated superior yields of high‐avidity CMVpp65 epitope‐specific T cells [cytomegalovirus‐cytotoxic T lymphocytes (CMV‐CTLs)] responding to ≤ 10^{? 13} M peptide concentrations, and lysing targets cells at lower effector : target ratios (1 : 10 and 1 : 100), where sIL‐15, sIL‐2 or sIL‐7 CMV‐CTLs demonstrated minimal or no activity. Both soluble and surface presented 15Rα/15, but not sIL‐15, sustained in‐vitro expansion of CD62L⁺ and CCR7⁺ central memory phenotype CMV‐CTLs (T_CM). 15Rα/15 complexes represent a potent adjuvant for augmenting the efficacy of adoptive immunotherapy. Such cell‐bound or soluble 15Rα/15 complexes could be developed for use in combination immunotherapy approaches.     

Uncoupling T-cell expansion from effector differentiation in cell-based immunotherapy

Adoptive cellular immunotherapy (ACT) is a potentially curative therapy for patients with advanced cancer. Eradication of tumor in mouse models and humans correlates with both a high dose of adoptively transferred cells and cells with a minimally differentiated phenotype that maintain replicative capacity and multipotency. We speculate that response to ACT not only requires transfer of cells with immediate cytolytic effector function to kill the bulk of fast-growing tumor but also transfer of tumor-specific cells that maintain an ability for self-renewal and the capacity to produce a continual supply of cytolytic effector progeny until all malignant cells are eliminated. Current in vitro methods to expand cells to sufficient numbers and still maintain a minimally differentiated phenotype are hindered by the biological coupling of clonal expansion and effector differentiation. Therefore, a better understanding of the physiologic mechanism that couples cell expansion and differentiation in CD8⁺ T cells may improve the efficacy of ACT.     

Significant anti-tumour activity of adoptively transferred T cells elicited by intratumoral dendritic cell vaccine injection through enhancing the ratio of CD8+ T cell/regulatory T cells in tumour

We have shown that immunization with dendritic cells (DCs) pulsed with hepatitis B virus core antigen virus‐like particles (HBc‐VLP) packaging with cytosine–guanine dinucleotide (CpG) (HBc‐VLP/CpG) alone were able to delay melanoma growth but not able to eradicate the established tumour in mice. We tested whether, by modulating the vaccination approaches and injection times, the anti‐tumour activity could be enhanced. We used a B16‐HBc melanoma murine model not only to compare the efficacy of DC vaccine immunized via footpads, intravenously or via intratumoral injections in treating melanoma and priming tumour‐specific immune responses, but also to observe how DC vaccination could improve the efficacy of adoptively transferred T cells to induce an enhanced anti‐tumour immune response. Our results indicate that, although all vaccination approaches were able to protect mice from developing melanoma, only three intratumoral injections of DCs could induce a significant anti‐tumour response. Furthermore, the combination of intratumoral DC vaccination and adoptive T cell transfer led to a more robust anti‐tumour response than the use of each treatment individually by increasing CD8⁺ T cells or the ratio of CD8⁺ T cell/regulatory T cells in the tumour site. Moreover, the combination vaccination induced tumour‐specific immune responses that led to tumour regression and protected surviving mice from tumour rechallenge, which is attributed to an increase in CD127‐expressing and interferon‐γ‐producing CD8⁺ T cells. Taken together, these results indicate that repeated intratumoral DC vaccination not only induces expansion of antigen‐specific T cells against tumour‐associated antigens in tumour sites, but also leads to elimination of pre‐established tumours, supporting this combined approach as a potent strategy for DC‐based cancer immunotherapy.     

Cancer immunotherapy: dawn of the death of cancer?

Abstract

Cancer is one of the proficient evaders of the immune system which claims millions of lives every year. Developing therapeutics against cancer is extremely challenging as cancer involves aberrations in self, most of which are not detected by the immune system. Conventional therapeutics like chemotherapy, radiotherapy are not only toxic but they significantly lower the quality of life. Immunotherapy, which gained momentum in the 20^th century, is emerging as one of the alternatives to the conventional therapies and is relatively less harmful but more costly. This review explores the modern advances in an array of such therapies and try to compare them along with a limited analysis of concerns associated with them.     

Adoptive immunotherapy with genetically modified lymphocytes in allogeneic stem cell transplantation

Hematopoietic stem cell transplantation from a healthy donor (allo-HSCT) represents the most potent form of cellular adoptive immunotherapy to treat malignancies. In allo-HSCT, donor T cells are double edge-swords: highly potent against residual tumor cells, but potentially highly toxic, and responsible for graft versus host disease (GVHD), a major clinical complication of transplantation. Gene transfer technologies coupled with current knowledge on cancer immunology have generated a wide range of approaches aimed at fostering the immunological response to cancer cells, while avoiding or controlling GVHD. In this review, we discuss cell and gene therapy approaches currently tested in preclinical models and in clinical trials.     

The in vitro generation of multi-tumor antigen-specific cytotoxic T cell clones: Candidates for leukemia adoptive immunotherapy following allogeneic stem cell transplantation

Adoptive T-cell immunotherapy is a promising approach to manage and maintain relapse-free survival of leukemia patients, especially following allogeneic stem cell transplantation. Post-transplant adoptive immunotherapy using cytotoxic T lymphocytes (CTLs) of the donor origin provide graft-versus-tumor effects, with or without graft–versus-host disease. Myeloid leukemias express immunogenic leukemia associated antigens (LAAs); such as WT-1, PRAME, MAGE, h-TERT and others, most of them are able to induce specific T cell responses whenever associated with the proper co-stimulation. We investigated the ability of a LAA-expressing hybridoma cell line to induce CTL clones in PBMCs of HLA-matched healthy donors in vitro. The CTL clones were induced by repetitive co-culture with LAAs-expressing, HLA-A*0201⁺ hybrid cell line, generated by fusion of leukemia blasts to human immortalized APC (EBV-sensitized B-lymphoblastoid cell line; HMy2). The induced cytotoxic T cell clones were phenotypically and functionally characterized by pentamer analysis, IFN-γ release ELISPOT and cellular cytotoxicity assays. All T cell lines showed robust peptide recognition and functional activity when sensitized with HLA-A*0201-restricted WT-1_235–243, hTERT_615–624 or PRAME_100–108 peptides-pulsed T2 cells, in addition to partially HLA-matched leukemia blasts. This study demonstrates the feasibility of developing multi-tumor antigen-specific T cell lines in allogeneic PBMCs in vitro, using LAA-expressing tumor/HMy2 hybrid cell line model, for potential use in leukemia adoptive immunotherapy in partially matched donor-recipient setting.     

Changes in urinary cytokines and soluble intercellular adhesion molecule-1 (ICAM-1) in bladder cancer patients after bacillus Calmette-Guérin (BCG) immunotherapy.

Intravesical immunotherapy for carcinoma in situ of the bladder is arguably the most effective form of tumour immunotherapy described to date. Following repeated instillations of BCG organisms into the bladder, large quantities of cytokines are detected in patients' urine. This study concerns the production of IL-1 beta, IL-2, IL-4, IL-6, IL-8, IL-10, tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) and soluble ICAM-1 (sICAM-1) throughout the six weekly instillations which comprise a therapeutic course. Sequential instillations of BCG induced secretion of IL-1 beta, IL-2, IL-6, IL-8, IL-10, TNF-alpha, IFN-gamma and sICAM-1 into urine. The responses were heterogeneous between patients and cytokines, but some general trends were evident. Although cytokine levels were initially low, their concentration increased with repeated instillation of BCG. Certain cytokines (e.g. IL-6, IL-8 and IL-10) could be detected after the first instillation, whilst others (e.g. IL-2 and IFN-gamma) were not detected until after the third or fourth instillation. Interestingly, IL-4 was not detected, perhaps suggesting a differential effect on Th2-like responses. Some patients produced particularly elevated or non-detectable levels of cytokines, and a positive correlation was found between the production of various cytokines. The production of a particular cytokine did not correspond with lack of production of another species. Whether monitoring the production of cytokines following therapy may be of prognostic value will be determined in a larger series of patients. However, as these potent immunomodulators are thought to be important for the 75% complete clinical response observed with BCG therapy, there remains the possibility that detection of the products of an activated immune system may correlate with eventual clinical outcome. This study is a necessary forerunner to full prognostic evaluation of such immunological data.     

IL-10 and TGF-beta cooperate in the regulatory T cell response to mucosal allergens in normal immunity and specific immunotherapy

The regulation of normal and allergic immune responses to airborne allergens in the mucosa is still poorly understood, and the mechanism of specific immunotherapy (SIT) in normalizing the allergic response to such allergens is currently not clear. Accordingly, we have investigated the immunoregulatory mechanism of both normal and allergic responses to the major house-dust mite (HDM) and birch pollen allergens--Dermatophagoides pteroynyssinus (Der p)1 and Bet v 1, respectively--as well as the immunologic basis of SIT to HDM in rhinitis and asthma patients. In normal immunity to HDM and birch pollen, an allergen-specific peripheral T cell suppression to Der p 1 and Bet v 1 was observed. The deviated immune response was characterized by suppressed proliferative T cell and Th1 (IFN-gamma) and Th2 (IL-5, IL-13) cytokine responses, and increased IL-10 and TGF-beta secretion by allergen-specific T cells. Neutralization of cytokine activity showed that T cell suppression was induced by IL-10 and TGF-beta during SIT and in normal immunity to the mucosal allergens. In addition, SIT induced an antigen-specific suppressive activity in CD4(+) CD25(+) T cells of allergic individuals. Together, these results demonstrate a deviation towards a regulatory/suppressor T cell response during SIT and in normal immunity as a key event for the healthy immune response to mucosal antigens.     

The transcription factor IRF2 drives interferon-mediated CD8+ T cell exhaustion to restrict anti-tumor immunity

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Lack of anti-tumour reactivity despite enhanced numbers of circulating natural killer T cells in two patients with metastatic renal cell carcinoma

Natural killer T (NK T) cells play a central role as intermediates between innate and adaptive immune responses important to induce anti-tumour reactivity in cancer patients. In two of 14 renal cell carcinoma (RCC) patients, treated with interferon (IFN)-α, we detected significantly enhanced numbers of circulating NK T cells which were typed phenotypically and analysed for anti-tumour reactivity. These NK T cells were T cell receptor (TCR) Vα24/Vβ11(+), 6B11(+) and bound CD1d tetramers. No correlation was observed between NK T frequencies and regulatory T cells (T(regs)), which were also enhanced. NK T cells expressed CD56, CD161, CD45RO and CD69 and were predominantly CD8(+), in contrast to the circulating T cell pool that contained both CD4(+) and CD8(+) T cells, as is found in healthy individuals. It is unlikely that IFN-α triggered the high NK T frequency, as all other patients expressed low to normal NK T numbers. A parallel was observed in IFN-α-related increase in activation of NK T cells with that in conventional T and non-T cells. Normal interleukin (IL)-7, IL-12 and IL-15 plasma levels were found. In one of the patients sporadic NK T cells were detected at the tumour site. α-Galactosylceramide (αGalCer) stimulation of peripheral blood mononuclear cells or isolated NK T cell lines from both patients induced IFN-γ, but no IL-4 and no response towards autologous tumour cells or lysates. The clinical course of disease in both patients was not exceptional with regard to histological subtype and extent of metastatic disease. Therefore, despite a constitutive high peripheral frequency and in vitroαGalCer responsiveness, the NK T cells in the two RCC patients did not show anti-tumour responsiveness.     

Immunotherapeutic targets in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is one of the most common types of cancer in the world and has a 5-year survival rate of ~20%. Immunotherapies have shown promising results leading to durable responses, however, they are only effective for a subset of patients. To determine the best therapeutic approach, a thorough and in-depth profiling of the tumour microenvironment (TME) is required. The TME is a complex network of cell types that form an interconnected network, promoting tumour cell initiation, growth and dissemination. The stroma, immune cells and endothelial cells that comprise the TME generate a plethora of cytotoxic or cytoprotective signalling pathways. In this review, we discuss immunotherapeutic targets in NSCLC tumours and how the TME may influence patients' response to immunotherapy.     

Updates on CAR T‐cell therapy in B‐cell malignancies

By increasing disease‐free survival and offering the potential for long‐term cure, chimeric antigen receptor (CAR) T‐cell therapy has dramatically expanded therapeutic options among those with high‐risk B‐cell malignancies. As CAR T‐cell utilization evolves however, novel challenges are generated. These include determining how to optimally integrate CAR T cells into standard of care and overcoming mechanisms of resistance to CAR T‐cell therapy, such as evolutionary stress induced on cancer cells leading to immunophenotypic changes that allow leukemia to evade this targeted therapy. Compounding these challenges are the limited ability to determine differences between various CAR T‐cell constructs, understanding the generalizability of trial outcomes from multiple sites utilizing unique CAR manufacturing strategies, and comparing distinct criteria for toxicity grading while defining optimal management. Additionally, as understanding of CAR behavior in humans has developed, strategies have appropriately evolved to proactively mitigate toxicities. These challenges offer complimentary insights and guide next steps to enhance the efficacy of this novel therapeutic modality. With a focus on B‐cell malignancies as the paradigm for effective CAR T‐cell therapy, this review describes advances in the field as well as current challenges and future directions.