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Multiple myeloma (MM) cells express certain tumour-associated antigens (TAAs) that could serve as targets for active-specific immunotherapy. The aim of the present study was to test the MM/dendritic cell (DC) fusion as a vaccination strategy. We fused MM cells with DC to generate fusion cells (FCs) and tested their antigen presenting cell (APC) function in mixed lymphocyte reactions and cytotoxicity assays. First, the HS Sultan and SK0-007 HAT sensitive human MM cell lines and DCs generated from peripheral blood of normal donors were fused in the presence of 50% polyethylene glycol to form FCs. Next, tumour cells freshly isolated from patients were similarly fused with autologous DCs to generate FCs. The FCs demonstrated a biphenotypic profile, confirmed both by flow-cytometry and dual immunofluorescence microscopy. These FCs induced MM-specific cytotoxicity. FCs, but not MM cells or DCs alone, were potent stimulators of autologous patient T cells. More importantly, FC-primed autologous peripheral blood mononuclear cells demonstrated major histocompatibility complex-restricted MM-specific cytolysis. These studies therefore demonstrated that MM/DC FC can trigger an autologous immune response to MM cells and formed the framework for a clinical trial currently underway. [ABSTRACT FROM AUTHOR]

The article focuses on factors of the tumour microenvironment are associated with patient survival and time to transformation in follicular lymphoma (FL). It mentions impact of PDCD1 (PD-1)-positive tumour infiltrating T-lymphocytes (TILs) and CD274 (PD-L1)-positive macrophages and single antibody for CD274. It also mentions immunohistochemical detection of CD274 in macrophages or the lymphoma cells and paraffin-embedded (FFPE) tissues.

Summary: Allogeneic immune responses underlie the graft‐versus‐leukaemia effect of stem cell transplantation, but disease relapse occurs in many patients. Minor histocompatibility antigen (mHAg) peptides mediate alloreactive T cell responses and induce graft‐versus‐leukaemia responses when expressed on patient haematopoietic tissue. We vaccinated nine HA‐1‐negative donors against HA‐1 with a 'prime–boost' protocol of either two or three DNA 'priming' vaccinations prior to 'boost' with modified vaccinia Ankara (MVA). HA‐1‐specific CD8+ T cell responses were observed in seven donors with magnitude up to 1·5% of total CD8+ T cell repertoire. HA‐1‐specific responses peaked two weeks post‐MVA challenge and were measurable in most donors after 12 months. HA‐1‐specific T cells demonstrated strong cytotoxic activity and lysed target cells with endogenous HA‐1 protein expression. The pattern of T cell receptor (TCR) usage by HA‐1‐specific T cells revealed strong conservation of T cell receptor beta variable 7‐9 (TRBV7‐9) usage between donors. These findings describe one of the strongest primary peptide‐specific CD8+ T cell responses yet recorded to a DNA–MVA prime–boost regimen and this may reflect the strong immunogenicity of mHAg peptides. Prime–boost vaccination in donors or patients may prove of substantial benefit in boosting graft‐versus‐leukaemia responses. [ABSTRACT FROM AUTHOR]

Summary: Viral infections are a serious cause of morbidity and mortality following haematopoietic stem cell transplantation (HSCT). Adoptive cellular therapy with virus‐specific T cells (VSTs) has been successful in preventing or treating targeted viruses in prior studies, but the composition of ex vivo expanded VST and the critical cell populations that mediate antiviral activity in vivo are not well defined. We utilized deep sequencing of the T‐cell receptor beta chain (TCRB) in order to classify and track VST populations in 12 patients who received VSTs following HSCT to prevent or treat viral infections. TCRB sequencing was performed on sorted VST products and patient peripheral blood mononuclear cells samples. TCRB diversity was gauged using the Shannon entropy index, and repertoire similarity determined using the Morisita–Horn index. Similarity indices reflected an early change in TCRB diversity in eight patients, and TCRB clonotypes corresponding to targeted viral epitopes expanded in eight patients. TCRB repertoire diversity increased in nine patients, and correlated with cytomegalovirus (CMV) viral load following VST infusion (P = 0·0071). These findings demonstrate that allogeneic VSTs can be tracked via TCRB sequencing, and suggests that T‐cell receptor repertoire diversity may be critical for the control of CMV reactivation after HSCT. [ABSTRACT FROM AUTHOR]

The success of genetically engineered T cells that express chimeric antigen receptors ( CARTs) has been a momentous step forward in harnessing the potent cancer fighting abilities of the immune system. The efficacy seen in relapsed/refractory (r/r) acute lymphoblastic leukaemia ( ALL), not only by inducing remission, but also in maintaining long-term disease control, has been unprecedented. While the foundation for this approach has been firmly set in place, continued development will improve the efficacy, toxicity and applicability to other malignancies of this new class of 'living drugs'. In this review, we provide a comprehensive overview of the most current clinical trial data in both acute and chronic leukaemias, and discuss some of the potential ways to enhance the activity and safety of CART therapy going forward. [ABSTRACT FROM AUTHOR]

In vitro discoveries have paved the way for bench-to-bedside translation in adoptive T cell immunotherapy, resulting in remarkable clinical responses in a variety of haematological malignancies. Adoptively transferred T cells genetically modified to express CD19 CARs have shown great promise, although many unanswered questions regarding how to optimize T-cell therapies for both safety and efficacy remain. Similarly, T cells that recognize viral or tumour antigens though their native receptors have produced encouraging clinical responses. Honing manufacturing processes will increase the availability of T-cell products, while combining T-cell therapies has the ability to increase complete response rates. Lastly, innovative mechanisms to control these therapies may improve safety profiles while genome editing offers the prospect of modulating T-cell function. This review will focus on recent advances in T-cell immunotherapy, highlighting both clinical and pre-clinical advances, as well as exploring what the future holds. [ABSTRACT FROM AUTHOR]

The article discusses the ibrutinib enhances the efficacy of ROR1 bispecific T cell engager mediated cytotoxicity in chronic lymphocytic leukaemia. Topics include how receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an onco-fetal antigen expressed in a range of solid and haematological malignancies, including acute lymphoblastic leukaemia (ALL) and chronic lymphocytic leukaemia.

The field of adoptive cell transfer includes chimeric antigen receptor (CAR) engineered T cells, constructs that emerged from basic research into principles of immunology and have transformed into clinically effective therapies for haematological malignancies. T cells engineered to express these artificial receptors hold great promise, but also carry significant risk. While permanent genetic modification of mature T cells appears safe, modulating their in vivo function is difficult, partly because the robust response can trigger other arms of the immune system. Suicide systems and toxicity management with cytokine blockade or signal transduction modulators have emerged as a new frontier in this field, a far cry from early problems getting CAR T cells to work at all. Currently, clinical trials in patients with relapsed or refractory B cell malignancies treated with CD19-specific CAR T cells have induced durable remissions in adults and children. Results from these trials indicate that more work needs to be done to understand biomarkers of efficacy, the role of T cell persistence and how to integrate this care into standard practice. Cell therapy will not be a 'one size fits all' class of medicine, and here we will discuss the development of this therapy and important questions for its future. [ABSTRACT FROM AUTHOR]

Dendritic cell (DC)-based immunotherapy faces new challenges because the efficacy of DC vaccines in clinical trials has been inconsistent. Strategies to improve immune responses induced by DC are currently being explored. We have recently shown the feasibility of generating fully functional DC from acute myeloid leukaemic (AML) blasts, but with varying expression levels of the important costimulatory molecule CD86. To overcome this variability, we developed a novel bispecific diabody that simultaneously and agonistically targeted CD40 on AML-DC and CD28 on naïve T cells. Beside optimization of CD28-mediated signalling, the resulting cellular cross-linking was also hypothesized to increase the strength and duration of T cell/AML-DC interactions, thus increasing T-cell responsiveness to AML antigens. The αCD40/αCD28-bispecific diabody was found to bind to its target antigens and provoked increased T-cell–DC cluster formation. The αCD40/αCD28 diabody is capable of increasing T-cell proliferation induced by AML-DC as well as the induction of DC maturation. Importantly, priming efficacy of tumour-specific cytotoxic T cells can also be improved by cross-linking AML-DC and T cells with the αCD40/αCD28 diabody. We propose that the αCD40/αCD28-bispecific diabody can serve as a potent therapeutic tool to effectively augment anti-tumour T-cell responses elicited by AML-DC. [ABSTRACT FROM AUTHOR]

Minor histocompatibility antigens (MiHA) selectively expressed by haematopoietic cells are attractive targets for specific immunotherapy after allogeneic stem cell transplantation (SCT). Previously, we described LRH-1 as a haematopoietic-lineage restricted MiHA that is capable of eliciting an allogeneic cytotoxic T-lymphocyte (CTL) response after SCT and donor lymphocyte infusion. Importantly, the gene encoding LRH-1, P2X5, is not expressed in prominent graft-versus-host-disease target tissues such as skin, liver and gut. Here, we investigate whether LRH-1-specific immunotherapy may be exploited for the treatment of lymphoid malignancies. We examined P2X5 mRNA expression in a large panel of patient samples and cell lines from different types of lymphoid malignancies by real-time quantitative reverse transcription polymerase chain reaction. P2X5 mRNA was highly expressed in malignant cells from all stages of lymphoid development. Furthermore, all LRH-1-positive lymphoid tumour cell lines were susceptible to LRH-1 CTL-mediated lysis in flow cytometry-based cytotoxicity assays. However, interferon-γ production was low or absent after stimulation with some cell lines, possibly due to differences in activation thresholds for CTL effector functions. Importantly, primary cells from patients with lymphoid malignancies were effectively lysed by LRH-1-specific CTL. These findings indicate that MiHA LRH-1 is a potential therapeutic target for cellular immunotherapy of lymphoid malignancies. [ABSTRACT FROM AUTHOR]

T-cell-mediated immunotherapy is a promising therapeutic option for multiple myeloma (MM). Gamma-delta T cells ( γ δ T cells) recognize phosphoantigens and display strong anti-tumour cytotoxicity. The synthetic agonist Phosphostim (bromohydrin pyrophosphate, BrHPP) has been shown to selectively activate V γ9V δ2 T cells. This study aimed to evaluate the expansion capacity and anti-myeloma cell cytotoxicity of circulating γ δ T cells from MM patients at different time points throughout the disease, using Phosphostim and interleukin 2 (IL-2). Circulating γ δ T cell counts in patients with newly diagnosed MM or in relapse did not differ from those in healthy donors. A 14-d culture of peripheral blood mononuclear cells with Phosphostim and IL-2 triggered a 100-fold expansion of γ δ T cells in 78% of newly diagnosed patients. γ δ T cells harvested at the time of haematopoietic progenitor collection or in relapsing patients expanded less efficiently. Expanded γ δ T cells killed 13/14 myeloma cell lines as well as primary myeloma cells, but not normal CD34 cells. Their killing efficiency was not affected by 2-d IL-2 starvation. This study demonstrated the ability of Phosphostim and IL-2 to expand γ δ T cells from MM patients, and the efficient and stable killing of human myeloma cells by gd T cells. [ABSTRACT FROM AUTHOR]

Haemolytic disease of the newborn (HDN) can be prevented by the passive administration of anti-D to the mother. The most accepted theory to describe this activity of anti-D is based upon its ability to clear opsonized erythrocytes before their recognition by the maternal immune system. We examined this hypothesis using a murine model of immunity to foreign erythrocytes. Whereas transfusion of foreign erythrocytes into mice induced immunoglobulin (Ig)M and IgG antibodies specific for the erythrocytes, these humoral immune responses were inhibited when the erythrocytes were opsonized with IgG. To specifically determine if immunological evasion occurs with these opsonized erythrocytes, we examined T-cell responses from these mice. An erythrocyte-specific T-cell response was clearly detected. We then tested whether phagocytosis of opsonized erythrocytes is sufficient to prevent the antibody response. We exposed mononuclear phagocytic cells to sheep red blood cells (SRBC) in vitro and then adoptively transferred the phagocytic cells to recipient mice; opsonized SRBC unexpectedly increased, rather than decreased, the antibody response. These data indicate that removal of opsonized erythrocytes by phagocytic cells does not prevent their immunological recognition and suggest that antigen clearance may not be the predominant mechanism of anti-erythrocyte action in downregulating the humoral immune response. [ABSTRACT FROM AUTHOR]

Adenoviral infections represent a major cause of morbidity and mortality following haematopoietic stem cell transplantation. Current anti-viral agents are virostatic and it is evident that elimination of adenovirus (ADV) infection is only achieved by recovery of cellular immunity. Using an interferongamma (IFN-γ) secretion and capture assay to isolate ADV-specific T cells, followed by a 2 week expansion and restimulation protocol, we generated ADV T cells that may be used for cellular immunotherapy. In contrast to virus-specific T cells for cytomegalovirus or Epstein-Barr virus, the ADV response was dominated by CD4+ T cells and the majority of captured cells exhibited an effector/memory immunophenotype. Highly specific antigen responses were demonstrated by intracellular IFN-c expression and cytotoxicity assays when the expanded cells underwent restimulation with ADV-pulsed target cells. Although T cells were initially generated in response to ADV species C, the expanded populations also showed strong activity against ADV species B, suggesting cross-reactivity across ADV species; a finding that has important clinical consequences in the paediatric setting, where the majority of infections are caused by ADV type B and C. The protocols can be readily translated to generate ADV-specific T cells suitable for clinical use and offer an effective immunotherapeutic strategy to control ADV infection. [ABSTRACT FROM AUTHOR]

During periods of immunosuppression, such as postallogeneic stem cell transplantation (SCT), patients are at significant risk for severe viral infections. Human adenovirus (HAdV) infection is a serious complication post-SCT, especially in children. Virus-specific T cells are essential for the clearance of HAdV, as antiviral chemotherapy has revealed limited success. We present feasibility data for a new treatment option using virus-specific donor T cells for adoptive transfer of immunity to patients with HAdV-infection/reactivation. Virus-specific donor T cells were isolated and infused into nine children with systemic HAdV infection after SCT. Isolation was based on γ-interferon (IFN- γ) secretion after short in vitro stimulation with viral antigen, resulting in a combination of CD4+ and CD8+ T cells. 1·2–50 × 103/kg T cells were infused for adoptive transfer. Isolated cells showed high specificity and markedly reduced alloreactivity in vitro. Adoptive transfer of HAdV-specific immunity was successful in five of six evaluable patients, documented by a dose-independent and sustained in vivo expansion of HAdV-specific T cells, associated with a durable clearance/decrease of viral copies. T-cell infusion was well tolerated in all nine patients, except one case with graft- versus-host disease II of the skin. In conclusion, induction of a specific T-cell response through adoptive transfer was feasible and effective. When performed early in the course of infection, adoptive T-cell transfer may protect from HAdV-related complications. [ABSTRACT FROM AUTHOR]

Adult T-cell leukaemia (ATL) is a peripheral T-cell neoplasm caused by human T-cell leukaemia virus type I (HTLV-I). Several clinical observations suggest that some tumour-associated antigens in ATL may be recognised by the immune system. In this study, we performed the serological screening of an expression library to identify ATL-associated antigens by using materials from a unique ATL patient with long-term stable disease. Among five distinct genes isolated, serine/arginine protein kinase 1 ( SRPK1), which has been reported to have a restricted normal tissue distribution, was found to be overexpressed in most acute type ATL samples, but not in chronic type ATL or in normal peripheral blood mononuclear cells by real-time reverse transcription polymerase chain reaction. Interestingly, the overexpression of SRPK1 in aggressive types of ATL was more exclusively observed at the protein level than at the mRNA level. Autologous antibody to SRPK1 was confirmed in the ATL patient using Western blot analysis with plasma, but not detected in asymptomatic HTLV-I carriers or in healthy volunteers. These results indicate that SRPK1 may be useful for the development of therapeutic and diagnostic methods for patients with ATL. [ABSTRACT FROM AUTHOR]

Weak immunogenicity of chronic lymphocytic leukaemia (CLL) cells may contribute to disease progression and inhibit the effectiveness of immunotherapies, such as vaccines. Agents that can enhance the antigen presenting capabilities of CLL cells might then help to improve the clinical results of immunotherapies. This study investigated the effects of the common gamma chain-binding cytokines, interleukin (IL)-2 and IL-15, on costimulatory properties of primary CLL cells from 51 patients. IL-2 improved the ability of CLL cells to stimulate T cell proliferation and increased the expression of costimulatory molecules (particularly CD80) in a dose-dependent fashion, especially in CLL cells with weak expression of CD38. CD80 and CD86 induction by IL-2 were positively regulated through the mitogen-activated protein kinase pathway, while CD86 expression was negatively regulated through Janus kinase pathways. However, further activation with protein kinase C agonists was required for IL-2 activated CLL cells to stimulate autologous T cells sufficiently to clear bystander CLL cells from mixed lymphocyte responses. IL-15 had similar effects on the costimulatory properties of CLL cells. These results suggest a role for IL-2, or IL-15, in immunotherapeutic strategies for CLL. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs) are the most potent antigen-presenting cells and are therefore an attractive option as antigen carriers in vaccination protocols. Chronic lymphocytic leukaemia (CLL) represents a potential good target for these approaches. The present study was designed to investigate the feasibility of generating in vitro fully functional DCs from peripheral blood (PB) monocytes of CLL patients at different phases of the disease. Although functional DCs could be obtained from CLL samples, in patients with active disease the expression of some co-stimulatory molecules appeared to be reduced. In contrast, DCs from CLL patients in remission showed no difference from those of normal controls. Moreover, patients with active disease produced DCs with reduced allostimulatory ability when compared with normal ones, whereas the functional capacities appeared to be restored in CLL DCs from remission patients. To more precisely assess the possible inhibitory effect of CLL cells on DC development, the influence of autologous leukaemic CD19+ cells on the generation of monocyte-derived CLL DCs in vitro was investigated. The addition of CLL neoplastic cells markedly affected monocyte-derived DC maturation. In conclusion, monocytes from CLL patients with active disease give rise to DCs, which show phenotypic and functional defects that are not observed in remission CLL patients. These results need to be taken into account in the design of DC-based immunotherapeutic approaches in CLL. [ABSTRACT FROM AUTHOR]

The poor response to immunotherapy in patients with multiple myeloma (MM) indicates that a better understanding of any defects in the immune response in these patients is required before effective therapeutic strategies can be developed. Recently we reported that high potency (CMRF44+) dendritic cells (DC) in the peripheral blood of patients with MM failed to significantly up-regulate the expression of the B7 co-stimulatory molecules, CD80 and CD86, in response to an appropriate signal from soluble trimeric human CD40 ligand. This defect was caused by transforming growth factor β1 (TGF β1) and interleukin (IL)-10, produced by malignant plasma cells, and the defect was neutralized in vitro with anti-TGF β1. As this defect could impact on immunotherapeutic strategies and may be a major cause of the failure of recent trials, it was important to identify a more clinically useful agent that could correct the defect in vivo. In this study of 59 MM patients, the relative and absolute numbers of blood DC were only significantly decreased in patients with stage III disease and CD80 up-regulation was reduced in both stage I and stage III. It was demonstrated that both IL-12 and interferon- γ neutralized the failure to stimulate CD80 up-regulation by huCD40LT in vitro. IL-12 did not cause a change in the distribution of DC subsets that were predominantly myeloid (CD11c+ and CDw123−) suggesting that there would be a predominantly T-helper cell type response. The addition of IL-12 or interferon- γ to future immunotherapy trials involving these patients should be considered. [ABSTRACT FROM AUTHOR]