During the last two decades, several approaches for the activation of the immune system against cancer have been developed. These include rather unselective maneuvers such as the systemic administration of immunostimulatory agents (e.g., interleukin-2) as well as targeted interventions, encompassing highly specific monoclonal antibodies, vaccines and cell-based therapies. Among the latter, adoptive cell transfer (ACT) involves the selection of autologous lymphocytes with antitumor activity, their expansion/activation ex vivo, and their reinfusion into the patient, often in the context of lymphodepleting regimens (to minimize endogenous immunosuppression). Such autologous cells can be isolated from tumor-infiltrating lymphocytes or generated by manipulating circulating lymphocytes for the expression of tumor-specific T-cell receptors. In addition, autologous lymphocytes can be genetically engineered to prolong their in vivo persistence, to boost antitumor responses and/or to minimize side effects. ACT has recently been shown to be associated with a consistent rate of durable regressions in melanoma and renal cell carcinoma patients and holds great promises in several other oncological settings. In this Trial Watch, we will briefly review the scientific rationale behind ACT and discuss the progress of recent clinical trials evaluating the safety and effectiveness of adoptive cell transfer as an anticancer therapy.

Adoptive cell transfer (ACT) represents a prominent form of immunotherapy against malignant diseases. ACT is conceptually distinct from dendritic cell-based approaches (which de facto constitute cellular vaccines) and allogeneic transplantation (which can be employed for the therapy of hematopoietic tumors) as it involves the isolation of autologous lymphocytes exhibiting antitumor activity, their expansion/activation ex vivo and their reintroduction into the patient. Re-infusion is most often performed in the context of lymphodepleting regimens (to minimize immunosuppression by host cells) and combined with immunostimulatory interventions, such as the administration of Toll-like receptor agonists. Autologous cells that are suitable for ACT protocols can be isolated from tumor-infiltrating lymphocytes or generated by engineering their circulating counterparts for the expression of transgenic tumor-specific T-cell receptors. Importantly, lymphocytes can be genetically modified prior to re-infusion for increasing their persistence in vivo, boosting antitumor responses and minimizing side effects. Moreover, recent data indicate that exhausted antitumor T lymphocytes may be rejuvenated in vitro by exposing them to specific cytokine cocktails, a strategy that might considerably improve the clinical success of ACT. Following up the Trial Watch that we published on this topic in the third issue of OncoImmunology (May 2012), here we summarize the latest developments in ACT-related research, covering both high-impact studies that have been published during the last 13 months and clinical trials that have been initiated in the same period to assess the antineoplastic profile of this form of cellular immunotherapy.

The expression "adoptive cell transfer" (ACT) is commonly employed to indicate an immunotherapeutic regimen involving the isolation of autologous blood-borne or tumor-infiltrating lymphocytes, their selection/expansion/activation ex vivo, and their reinfusion into the patient, most often in the context of lymphodepleting pre-conditioning and in combination with immunostimulatory treatments. Optionally, the cellular material for ACT is genetically manipulated before expansion to (1) target specific tumor-associated antigens; (2) endogenously express immunostimulatory molecules; and/or (3) persist for long periods upon reinfusion. Consistent efforts have been dedicated at the amelioration of this immunotherapeutic regimen throughout the past decade, resulting in the establishment of ever more efficient and safer ACT protocols. Accordingly, the number of clinical trials testing ACT in oncological indications does not cease to increase. In this Trial Watch, we summarize recent developments in this exciting area of research, covering both high-impact studies that have been published during the last 12 months and clinical trials that have been launched in the same period to evaluate the safety and therapeutic potential of ACT in cancer patients.

Cancer immunotherapy is recently considered the most promising treatment for human patients with advanced tumors and could be effectively combined with conventional therapies such as chemotherapy or radiotherapy. Patients with hematological malignancies and melanoma have benefited greatly from immunotherapies such as, adoptive cell transfer therapy, experiencing durable remissions and prolonged survival. In the face of increasing enthusiasm for immunotherapy, particularly for the administration of tumor-specific T lymphocytes, the question arises whether this method could be employed to improve treatment outcomes for canine patients. It is warranted to determine whether veterinary clinical trials could support comparative oncology research and thus facilitate the development of new cell-based therapies for humans. Herein, we discuss adoptive transfer of T lymphocytes and lymphokine-activated cells for application in veterinary oncology, in the context of human medicine achievements. Furthermore, we discuss potential benefits of using domestic dog as a model for immunotherapy and its advantages for translational medicine. We also focus on an emerging genome-editing technology as a useful tool to improve a T cells' phenotype.

Adoptive cell therapy (ACT) is a highly personalized cancer therapy that involves administration to the cancer-bearing host of immune cells with direct anticancer activity. ACT using naturally occurring tumor-reactive lymphocytes has mediated durable, complete regressions in patients with melanoma, probably by targeting somatic mutations exclusive to each cancer. These results have expanded the reach of ACT to the treatment of common epithelial cancers. In addition, the ability to genetically engineer lymphocytes to express conventional T cell receptors or chimeric antigen receptors has further extended the successful application of ACT for cancer treatment.

Adoptive Cell Transfer (ACT) of Tumor-Infiltrating Lymphocytes (TIL) in combination with lymphodepletion has proven to be an effective treatment for metastatic melanoma patients, with an objective response rate in 50%-70% of the patients. It is based on the ex vivo expansion and activation of tumor-specific T lymphocytes extracted from the tumor and their administration back to the patient. Various TIL-ACT trials, which differ in their TIL generation procedures and patient preconditioning, have been reported. In the latest clinical studies, genetically engineered peripheral T cells were utilized instead of TIL. Further improvement of adoptive T cell transfer depends on new investigations which seek higher TIL quality, increased durable response rates, and aim to treat more patients. Simplifying this therapy may encourage cancer centers worldwide to adopt this promising technology. This paper focuses on the latest progress regarding adoptive T cell transfer, comparing the currently available protocols and discussing their advantages, disadvantages, and implication in the future.

Adoptive transfer experimental autoimmune encephalomyelitis (AT-EAE) is an inflammatory demyelination that recapitulates in mouse spinal cord (SC) the human multiple sclerosis disease. We now analyze previously reported cDNA array data from age-matched young female adult control and passively myelin antigen-sensitized EAE mice with regard to organizational principles of the SC transcriptome in autoimmune demyelination. Although AT-EAE had a large impact on immune response genes, broader functional and chromosomal gene cohorts were neither significantly regulated nor showed significant changes in expression coordination. However, overall transcriptional control was increased in AT-EAE and the proportions of transcript abundances were perturbed within each cohort. Striking likenesses and oppositions were identified in the coordination profiles of genes related to myelination, calcium signaling, and inflammatory response in controls that were substantially altered in AT-EAE. We propose that up- or down-regulation of genes linked to those targeted by the disease could potentially compensate for the pathological transcriptomic changes.

The mixed chimerism approach is an exceptionally potent strategy for the induction of donor-specific tolerance in organ transplantation and so far the only one that was demonstrated to work in the clinical setting. Regulatory T cells (Tregs) have been shown to improve chimerism induction in experimental animal models. This review summarizes the development of innovative BMT protocols using therapeutic Treg transfer for tolerance induction.

During the inflammation which occurs following nerve damage, macrophages are recruited to the site of injury. Phenotypic diversity is a hallmark of the macrophage lineage and includes pro-inflammatory M1 and anti-inflammatory M2 populations. Our aim in this study was to investigate the ability of polarized M0, M1, and M2 macrophages to secrete opioid peptides and to examine their relative contribution to the modulation of neuropathic pain.

Prophylactic strategies to prevent the development of allergies by establishing tolerance remain an unmet medical need. We previously reported that the transfer of autologous hematopoietic stem cells (HSC) expressing the major timothy grass pollen allergen, Phl p 5, on their cell surface induced allergen-specific tolerance in mice. In this study, we investigated the ability of allergen-expressing immune cells (dendritic cells, CD4+ T cells, CD8+ T cells, and CD19+ B cells) to induce allergen-specific tolerance in naive mice and identified CD19+ B cells as promising candidates for allergen-specific cell therapy.

Both nature and induced regulatory T (Treg) lymphocytes are potent regulators of autoimmune and allergic disorders. Defects in endogenous Treg cells have been reported in patients with allergic asthma, suggesting that disrupted Treg cell-mediated immunological regulation may play an important role in airway allergic inflammation. In order to determine whether adoptive transfer of induced Treg cells generated in vitro can be used as an effective therapeutic approach to suppress airway allergic inflammation, exogenously induced Treg cells were infused into ovalbumin-sensitized mice prior to or during intranasal ovalbumin challenge. The results showed that adoptive transfer of induced Treg cells prior to allergen challenge markedly reduced airway hyperresponsiveness, eosinophil recruitment, mucus hyper-production, airway remodeling, and IgE levels. This effect was associated with increase of Treg cells (CD4(+)FoxP3(+)) and decrease of dendritic cells in the draining lymph nodes, and with reduction of Th1, Th2, and Th17 cell response as compared to the controls. Moreover, adoptive transfer of induced Treg cells during allergen challenge also effectively attenuate airway inflammation and improve airway function, which are comparable to those by natural Treg cell infusion. Therefore, adoptive transfer of in vitro induced Treg cells may be a promising therapeutic approach to prevent and treat severe asthma.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive tumor. Prognosis is poor and survival is low in patients diagnosed with this disease, with a survival rate of ~12% at 5 years. Immunotherapy, including adoptive T cell transfer therapy, has not impacted the outcomes in patients with PDAC, due in part to the hostile tumor microenvironment (TME) which limits T cell trafficking and persistence. We posit that murine models serve as useful tools to study the fate of T cell therapy. Currently, genetically engineered mouse models (GEMMs) for PDAC are considered a "gold-standard" as they recapitulate many aspects of human disease. However, these models have limitations, including marked tumor variability across individual mice and the cost of colony maintenance.

Sphingolipids regulate critical cellular processes including inflammation. Ceramide, which serves a central role in sphingolipid metabolism, is generated by six ceramide synthases (CerS) that differ in substrate specificity. CerS6 preferentially generates C16-ceramide and its mRNA is highly expressed in immune tissues. In this study we analyzed how deficiency of CerS6 impacts on the development of colitis using an adoptive transfer model. Adoptive transfer of CerS6-deficient splenocytes, which have significantly decreased levels of C16-ceramide, showed that CerS6-deficiency protected against the development of colitis. However, adoptively transferred cells isolated from the lamina propria of the large intestine from wild type or CerS6-deficient groups showed no differences in the percentages of immune-suppressive regulatory T cells, pro-inflammatory Th17 cells, or their ability to express IL-17. In vitro polarization of wild type or CerS6-deficient splenocytes also revealed no defects in the development of T cell subsets. Our data suggest that protection from colitis following adoptive transfer of CerS6-deficient splenocytes maybe related to their ability to migrate and proliferate in vivo rather than subset development or cytokine expression.

Studies showed that specific probiotics provide therapeutic benefits in inflammatory bowel disease. In vitro evidence suggested that Lactobacillus paracasei also called ST11 (CNCM I-2116) is a potent strain with immune modulation properties. However, little is known about its capacity to alleviate inflammatory symptoms in vivo In this context, the main objective of this study was to investigate the role of ST11 on intestinal inflammation using the adoptive transfer mouse model of experimental colitis. Rag2(-/-) recipient mice were fed with ST11 (10(9) CFU/day)a month prior toinduce colitis by adoptive transfer of naive T cells. One month later, in clear contrast to nonfed mice, weight loss was significantly reduced by 50% in ST11-fed mice. Further analysis of colon specimens revealed a significant reduction neutrophil infiltration and mucosal expression of IL1β, IL-6, and IL12 proinflammatory cytokines, whereas no consistent differences in expression of antibacterial peptides or tight junction proteins were observed between PBS and ST11-fed mice. All together, our results demonstrate that oral administration of ST11 was safe and had a significant preventive effect on colitis. We conclude that probiotics such as Lactobacillus paracasei harbor worthwhile in vivo immunomodulatory properties to prevent intestinal inflammation by nutritional approaches.

Macrophages are multifunctional immune cells that may either drive or modulate disease pathogenesis depending on their activation phenotype. Autoimmune type 1 diabetes (T1D) is a chronic proinflammatory condition characterized by unresolved destruction of pancreatic islets. Adoptive cell transfer of macrophages with immunosuppressive properties represents a novel immunotherapy for treatment of such chronic autoimmune diseases. We used a panel of cytokines and other stimuli to discern the most effective regimen for in vitro induction of immunosuppressive macrophages (M2r) and determined interleukin (IL)-4/IL-10/transforming growth factor-β (TGF-β) to be optimal. M2r cells expressed programmed cell death 1 ligand-2, fragment crystallizable region γ receptor IIb, IL-10, and TGF-β, had a potent deactivating effect on proinflammatory lipopolysaccharide/interferon-γ-stimulated macrophages, and significantly suppressed T-cell proliferation. Clinical therapeutic efficacy was assessed after adoptive transfer in NOD T1D mice, and after a single transfer of M2r macrophages, >80% of treated NOD mice were protected against T1D for at least 3 months, even when transfer was conducted just prior to clinical onset. Fluorescent imaging analyses revealed that adoptively transferred M2r macrophages specifically homed to the inflamed pancreas, promoting β-cell survival. We suggest that M2r macrophage therapy represents a novel intervention that stops ongoing autoimmune T1D and may have relevance in a clinical setting.

A fluorescence-based, high-resolution imaging approach was used to visualize longitudinally the cellular events unfolding during T cell-mediated tumor destruction. The dynamic interplay of T cells, cancer cells, cancer antigen loss variants, and stromal cells-all color-coded in vivo-was analyzed in established, solid tumors that had developed behind windows implanted on the backs of mice. Events could be followed repeatedly within precisely the same tumor region-before, during and after adoptive T cell therapy-thereby enabling for the first time a longitudinal in vivo evaluation of protracted events, an analysis not possible with terminal imaging of surgically exposed tumors. T cell infiltration, stromal interactions, and vessel destruction, as well as the functional consequences thereof, including the elimination of cancer cells and cancer cell variants were studied. Minimal perivascular T cell infiltrates initiated vascular destruction inside the tumor mass eventually leading to macroscopic central tumor necrosis. Prolonged engagement of T cells with tumor antigen-crosspresenting stromal cells correlated with high IFNγ cytokine release and bystander elimination of antigen-negative cancer cells. The high-resolution, longitudinal, in vivo imaging approach described here will help to further a better mechanistic understanding of tumor eradication by T cells and other anti-cancer therapies.

Cardiac fibrogenesis in the late stage of viral myocarditis causing contractile dysfunction and ventricular dilatation, is a major pathogenic factor for the progression of myocarditis to serious cardiovascular diseases including dilated cardiomyopathy (DCM) and congestive heart failure (HF). Recent studies indicate that regulatory T cells (Tregs) are involved in the fibrotic process of liver and lung fibosis. However, the role of Tregs in the development of viral myocarditis-caused cardiac fibrosis and their therapeutic potential remains unclear.

Retroviral gene transfer of interleukin-12 (IL-12) into T cells markedly enhances antitumor efficacy upon adoptive transfer but has clinically shown unacceptable severe side effects. To overcome the toxicity, we engineered tumor-specific CD8+ T cells to transiently express IL-12. Engineered T cells injected intratumorally, but not intravenously, led to complete rejections not only of the injected lesion but also of distant concomitant tumors. Efficacy was further enhanced by co-injection with agonist anti-CD137 mAb or by transient co-expression of CD137 ligand. This treatment induced epitope spreading of the endogenous CD8+ T cell immune response in a manner dependent on cDC1 dendritic cells. Mouse and human tumor-infiltrating T lymphocyte cultures can be transiently IL-12 engineered to attain marked immunotherapeutic effects.

Atherosclerosis is characterized by inflammation in the arterial wall, which is known to be exacerbated by diabetes. Therapeutic repression of inflammation is a promising strategy for treating atherosclerosis. In this study, we showed that diabetes aggravated atherosclerosis in apolipoproteinE knockout (ApoE -/-) mice, in which increased expression of long-chain acyl-CoA synthetase 1 (Acsl1) in macrophages played an important role. Knockdown of Acsl1 in macrophages (Mφ shAcsl1 ) reprogrammed macrophages to an anti-inflammatory phenotype, especially under hyperglycemic conditions. Injection of Mφ shAcsl1 reprogrammed macrophages into streptozotocin (STZ)-induced diabetic ApoE -/- mice (ApoE -/-+ STZ) alleviated inflammation locally in the plaque, liver and spleen. Consistent with the reduction in inflammation, plaques became smaller and more stable after the adoptive transfer of reprogrammed macrophages. Taken together, our findings indicate that increased Acsl1 expression in macrophages play a key role in aggravated atherosclerosis of diabetic mice, possibly by promoting inflammation. Adoptive transfer of Acsl1 silenced macrophages may serve as a potential therapeutic strategy for atherosclerosis.

The high metabolic activity and insufficient perfusion of tumors leads to the acidification of the tumor microenvironment (TME) that may inhibit the antitumor T cell activity. We found that pharmacological inhibition of the acid loader chloride/bicarbonate anion exchanger 2 (Ae2), with 4,4'-diisothiocyanatostilbene-2,2'-disulfonicacid (DIDS) enhancedCD4+ andCD8+ T cell function upon TCR activation in vitro, especially under low pH conditions. In vivo, DIDS administration delayed B16OVA tumor growth in immunocompetent mice as monotherapy or when combined with adoptive T cell transfer of OVA-specificT cells. Notably, genetic Ae2 silencing in OVA-specificT cells improvedCD4+/CD8+ T cell function in vitro as well as their antitumor activity in vivo. Similarly, genetic modification of OVA-specificT cells to overexpress Hvcn1, a selectiveH+ outward current mediator that prevents cell acidification, significantly improved T cell function in vitro, even at low pH conditions. The adoptive transfer of OVA-specificT cells overexpressing Hvcn1 exerted a better antitumor activity in B16OVA tumor-bearingmice. Hvcn1 overexpression also improved the antitumor activity of CAR T cells specific for Glypican 3 (GPC3) in mice bearing PM299L-GPC3tumors. Our results suggest that preventing intracellular acidification by regulating the expression of acidifier ion channels such as Ae2 or alkalinizer channels like Hvcn1 in tumor-specificlymphocytes enhances their antitumor response by making them more resistant to the acidic TME.