Antigen-independent induction of Tim-3 expression on human T cells by the common γ-chain cytokines IL-2, IL-7, IL-15, and IL-21 is associated with proliferation and is dependent on the phosphoinositide 3-kinase pathway

Generation and Characterization of Ex Vivo Expanded Tumor-infiltrating Lymphocytes From Renal Cell Carcinoma Tumors for Adoptive Cell Therapy

Autologous therapeutic tumor-infiltrating lymphocyte (TIL) therapy is a promising strategy to enhance antitumor immunity. Optimization of ex vivo TIL expansion could expand current immunotherapy options. Previous attempts to generate TIL in renal cell carcinoma (RCC) have been technically challenging. We applied a second-generation manufacturing process, currently used to generate the melanoma TIL product lifileucel, in RCC. Resected primary and metastatic RCC samples were processed using the Gen 2 manufacturing process comprising of pre-Rapid Expansion Protocol (pre-REP) and REP steps. We assessed REP TILs for viability and performed phenotypic and functional characterization. We correlated the tumor immune microenvironment (TIME) with successful TIL expansion. Eight of 11 RCC samples underwent successful REP. Three failed cases demonstrated low CD8/FoxP3 ratio and high expression of PD-1 within FoxP3 cells. Expression of exhaustion markers differed between the TIME and expanded TILs; the latter had a TIM3-high/PD-1-low phenotype but retained functional capacity comparable to lifileucel. The Gen 2 manufacturing process used for lifileucel successfully expanded functional TILs from RCC samples, enabling further study in a clinical trial. TIME features such as low CD8/FoxP3 ratio and high PD-1 expression within FoxP3 cells warrant study as potential biomarkers of successful TIL expansion.

Engineering Improved CAR T Cell Products with A Multi-Cytokine Particle Platform for Hematologic and Solid Tumors

Despite the remarkable clinical efficacy of chimeric antigen receptor (CAR) T cells in hematological malignancies, only a subset of patients achieves a durable complete response (dCR). DCR has been correlated with CAR T cell products enriched with T cells memory phenotypes. Therefore, reagents that consistently promote memory phenotypes during the manufacturing of CAR T cells have the potential to significantly improve clinical outcomes. A novel modular multi-cytokine particle (MCP) platform is developed that combines the signals necessary for activation, costimulation, and cytokine support into a single "all-in-one" stimulation reagent for CAR T cell manufacturing. This platform allows for the assembly and screening of compositionally diverse MCP libraries to identify formulations tailored to promote specific phenotypes with a high degree of flexibility. The approach is leveraged to identify unique MCP formulations that manufacture CAR T cell products from diffuse large B cell patients   with increased proportions of memory-like phenotypes MCP-manufactured CAR T cells demonstrate superior anti-tumor efficacy in mouse models of lymphoma and ovarian cancer through enhanced persistence. These findings serve as a proof-of-principle of the powerful utility of the MCP platform to identify "all-in-one" stimulation reagents that can improve the effectiveness of cell therapy products through optimal manufacturing.

Spatial and functional targeting of intratumoral Tregs reverses CD8+ T cell exhaustion and promotes cancer immunotherapy

Intratumoral Tregs are key mediators of cancer immunotherapy resistance, including anti-programmed cell death (ligand) 1 [anti-PD-(L)1] immune checkpoint blockade (ICB). The mechanisms driving Treg infiltration into the tumor microenvironment (TME) and the consequence on CD8+ T cell exhaustion remain elusive. Here, we report that heat shock protein gp96 (also known as GRP94) was indispensable for Treg tumor infiltration, primarily through the roles of gp96 in chaperoning integrins. Among various gp96-dependent integrins, we found that only LFA-1 (αL integrin), and not αV, CD103 (αE), or β7 integrin, was required for Treg tumor homing. Loss of Treg infiltration into the TME by genetic deletion of gp96/LFA-1 potently induced rejection of tumors in multiple ICB-resistant murine cancer models in a CD8+ T cell-dependent manner, without loss of self-tolerance. Moreover, gp96 deletion impeded Treg activation primarily by suppressing IL-2/STAT5 signaling, which also contributed to tumor regression. By competing for intratumoral IL-2, Tregs prevented the activation of CD8+ tumor-infiltrating lymphocytes, drove thymocyte selection-associated high mobility group box protein (TOX) induction, and induced bona fide CD8+ T cell exhaustion. By contrast, Treg ablation led to striking CD8+ T cell activation without TOX induction, demonstrating clear uncoupling of the 2 processes. Our study reveals that the gp96/LFA-1 axis plays a fundamental role in Treg biology and suggests that Treg-specific gp96/LFA-1 targeting represents a valuable strategy for cancer immunotherapy without inflicting autoinflammatory conditions.

Placental circulating T cells: a novel, allogeneic CAR-T cell platform with preserved T-cell stemness, more favorable cytokine profile, and durable efficacy compared to adult PBMC-derived CAR-T

BACKGROUND

Chimeric antigen receptor (CAR)-T cell quality and stemness are associated with responsiveness, durability, and memory formation, which benefit clinical responses. Autologous T cell starting material across patients with cancer is variable and CAR-T expansion or potency can fail during manufacture. Thus, strategies to develop allogeneic CAR-T platforms including the identification and expansion of T cell subpopulations that correspond with CAR-T potency are an active area of investigation. Here, we compared CAR-T cells generated from healthy adult peripheral blood T cells versus placental circulating T (P-T) cells.

METHODS

CAR-T cells from healthy adult peripheral blood mononuclear cells (PBMCs) and P-T cells were generated using the same protocol. CAR-T cells were characterized in detail by a combination of multiparameter flow cytometry, functional assays, and RNA sequencing. In vivo antitumor efficacy and persistence of CAR-T cells were evaluated in a Daudi lymphoma xenograft model.

RESULTS

P-T cells possess stemness advantages compared with T cells from adult PBMCs. P-T cells are uniformly naïve prior to culture initiation, maintain longer telomeres, resist immune checkpoint upregulation, and resist further differentiation compared with PBMC T cells during CD19 CAR-T manufacture. P-T CD19 CAR-T cells are equally cytotoxic as PBMC-CD19 CAR-T cells but produce less interferon gamma in response to lymphoma. Transcriptome analysis shows P-T CD19 CAR-T cells retain a stem-like gene signature, strongly associate with naïve T cells, an early memory phenotype, and a unique CD4 T cell signature compared with PBMC-CD19 CAR-T cells, which enrich for exhaustion and stimulated memory T cell signatures. Consistent with functional data, P-T CD19 CAR-T cells exhibit attenuated inflammatory cytokine and chemokine gene signatures. In a murine in vivo model, P-T CD19 CAR-T cells eliminate lymphoma beyond 90 days. PBMC-CD19 CAR-T cells provide a non-durable benefit, which only delays disease onset.

CONCLUSION

We identified characteristics of T cell stemness enriched in P-T CD19 CAR-T which are deficient in PBMC-derived products and translate into response durability in vivo. Our findings demonstrate that placental circulating T cells are a valuable cell source for allogeneic CAR-T products. Stemness advantages inherent to P-T cells translate to in vivo persistence advantages and long-term durable activity.

Galectin-9 alleviates acute graft-versus-host disease after haplo-hematopoietic stem cell transplantation by regulating regulatory T cell/effector T cell imbalance

BACKGROUND

Acute graft-versus-host disease (aGVHD) arises from the imbalance of host T cells. Galectin-9 negatively regulates CD4 effector T cell (Th1 and Th17) function by binding to Tim-3. However, the relationship between Galectin-9/Tim-3 and CD4+ T subsets in patients with aGVHD after Haplo-HSCT (haploidentical peripheral blood hematopoietic stem cell transplantation) has not been fully elucidated. Here, we investigated the role of Galectin-9 and CD4+ T subsets in aGVHD after haplo-HSCT.

METHODS

Forty-two patients underwent Haplo-HSCT (26 without aGVHD and 16 with aGVHD), and 20 healthy controls were included. The concentrations of Galectin-9, interferon-gamma (IFN-γ), interleukin (IL)-4, transforming growth factor (TGF)-β, and IL-17 in the serum and culture supernatant were measured using enzyme-linked immunosorbent assay or cytometric bead array. The expression levels of Galectin-9, PI3K, p-PI3K, and p-mTOR protein were detected by western blot analysis. Flow cytometry was used to analyze the proportions of CD4+ T cell subsets. Bioinformatics analysis was performed.

RESULTS

In patients with aGVHD, regulatory T (Treg) cells and Galectin-9 decreased, and the Th1, Th17, and Treg cells were significantly imbalanced. Moreover, Treg and Galectin-9 were rapidly reconstituted in the early stage of patients without aGVHD after Haplo-HSCT, but Th17 cells were reconstituted slowly. Furthermore, Tim-3 upregulation on Th17 and Th1 cells was associated with excessive activation of the PI3K/AKT pathway in patients with aGVHD. Specifically, in vitro treatment with Galectin-9 reduced IFN-γ and IL-17 production while augmenting TGF-β secretion. Bioinformatics analysis suggested the potential involvement of the PI3K/AKT/mTOR pathway in aGVHD. Mechanistically, exogenous Galectin-9 was found to mitigate aGVHD by restoring the Treg/Teffs (effector T cells) balance and suppressing PI3K.

CONCLUSION

Galectin-9 may ameliorate aGVHD after haplo-HSCT by modulating Treg/Teffs balance and regulating the PI3K/AKT/mTOR pathway. Targeting Galectin-9 may hold potential value for the treatment of aGVHD.

Combinatorial blockade for cancer immunotherapy: targeting emerging immune checkpoint receptors

The differentiation, survival, and effector function of tumor-specific CD8+ cytotoxic T cells lie at the center of antitumor immunity. Due to the lack of proper costimulation and the abundant immunosuppressive mechanisms, tumor-specific T cells show a lack of persistence and exhausted and dysfunctional phenotypes. Multiple coinhibitory receptors, such as PD-1, CTLA-4, VISTA, TIGIT, TIM-3, and LAG-3, contribute to dysfunctional CTLs and failed antitumor immunity. These coinhibitory receptors are collectively called immune checkpoint receptors (ICRs). Immune checkpoint inhibitors (ICIs) targeting these ICRs have become the cornerstone for cancer immunotherapy as they have established new clinical paradigms for an expanding range of previously untreatable cancers. Given the nonredundant yet convergent molecular pathways mediated by various ICRs, combinatorial immunotherapies are being tested to bring synergistic benefits to patients. In this review, we summarize the mechanisms of several emerging ICRs, including VISTA, TIGIT, TIM-3, and LAG-3, and the preclinical and clinical data supporting combinatorial strategies to improve existing ICI therapies.

Mesothelin-targeting T cell receptor fusion construct cell therapy in refractory solid tumors: phase 1/2 trial interim results

The T cell receptor fusion construct (TRuC) gavocabtagene autoleucel (gavo-cel) consists of single-domain anti-mesothelin antibody that integrates into the endogenous T cell receptor (TCR) and engages the signaling capacity of the entire TCR upon mesothelin binding. Here we describe phase 1 results from an ongoing phase1/2 trial of gavo-cel in patients with treatment-refractory mesothelin-expressing solid tumors. The primary objectives were to evaluate safety and determine the recommended phase 2 dose (RP2D). Secondary objectives included efficacy. Thirty-two patients received gavo-cel at increasing doses either as a single agent (n = 3) or after lymphodepletion (LD, n = 29). Dose-limiting toxicities of grade 3 pneumonitis and grade 5 bronchioalveolar hemorrhage were noted. The RP2D was determined as 1 × 108 cells per m2 after LD. Grade 3 or higher pneumonitis was seen in 16% of all patients and in none at the RP2D; grade 3 or higher cytokine release syndrome occurred in 25% of all patients and in 15% at the RP2D. In 30 evaluable patients, the overall response rate and disease control rate were 20% (13% confirmed) and 77%, respectively, and the 6-month overall survival rate was 70%. Gavo-cel warrants further study in patients with mesothelin-expressing cancers given its encouraging anti-tumor activity, but it may have a narrow therapeutic window. ClinicalTrials.gov identifier: NCT03907852 .

STAT3 regulates CD8+ T cell differentiation and functions in cancer and acute infection

In cancer, persistent antigens drive CD8+ T cell differentiation into exhausted progenitor (Texprog) and terminally exhausted (Texterm) cells. However, how the extrinsic and intrinsic regulatory mechanisms cooperate during this process still remains not well understood. Here, we found that STAT3 signaling plays essential roles in promoting intratumor Texterm cell development by enhancing their effector functions and survival, which results in better tumor control. In tumor microenvironments, STAT3 is predominantly activated by IL-10 and IL-21, but not IL-6. Besides, STAT3 also plays critical roles in the development and function of terminally differentiated effector CD8+ T cells in acute infection. Mechanistically, STAT3 transcriptionally promotes the expression of effector function-related genes, while it suppresses those expressed by the progenitor Tex subset. Moreover, STAT3 functions in collaboration with BATF and IRF4 to mediate chromatin activation at the effector gene loci. Thus, we have elucidated the roles of STAT3 signaling in terminally differentiated CD8+ T cell development, especially in cancer, which benefits the development of more effective immunotherapies against tumors.

Non-viral precision T cell receptor replacement for personalized cell therapy

T cell receptors (TCRs) enable T cells to specifically recognize mutations in cancer cells1-3. Here we developed a clinical-grade approach based on CRISPR-Cas9 non-viral precision genome-editing to simultaneously knockout the two endogenous TCR genes TRAC (which encodes TCRα) and TRBC (which encodes TCRβ). We also inserted into the TRAC locus two chains of a neoantigen-specific TCR (neoTCR) isolated from circulating T cells of patients. The neoTCRs were isolated using a personalized library of soluble predicted neoantigen-HLA capture reagents. Sixteen patients with different refractory solid cancers received up to three distinct neoTCR transgenic cell products. Each product expressed a patient-specific neoTCR and was administered in a cell-dose-escalation, first-in-human phase I clinical trial ( NCT03970382 ). One patient had grade 1 cytokine release syndrome and one patient had grade 3 encephalitis. All participants had the expected side effects from the lymphodepleting chemotherapy. Five patients had stable disease and the other eleven had disease progression as the best response on the therapy. neoTCR transgenic T cells were detected in tumour biopsy samples after infusion at frequencies higher than the native TCRs before infusion. This study demonstrates the feasibility of isolating and cloning multiple TCRs that recognize mutational neoantigens. Moreover, simultaneous knockout of the endogenous TCR and knock-in of neoTCRs using single-step, non-viral precision genome-editing are achieved. The manufacture of neoTCR engineered T cells at clinical grade, the safety of infusing up to three gene-edited neoTCR T cell products and the ability of the transgenic T cells to traffic to the tumours of patients are also demonstrated.

Universal allogeneic CAR T cells engineered with Sleeping Beauty transposons and CRISPR-CAS9 for cancer immunotherapy

Allogeneic CD19-specific chimeric antigen receptor (CAR) T cells with inactivated donor T cell receptor (TCR) expression can be used as an "off-the-shelf" therapeutic modality for lymphoid malignancies, thus offering an attractive alternative to autologous, patient-derived T cells. Current approaches for T cell engineering mainly rely on the use of viral vectors. Here, we optimized and validated a non-viral genetic modification platform based on Sleeping Beauty (SB) transposons delivered with minicircles to express CD19-28z.CAR and CRISPR-Cas9 ribonucleoparticles to inactivate allogeneic TCRs. Efficient TCR gene disruption was achieved with minimal cytotoxicity and with attainment of robust and stable CD19-28z.CAR expression. The CAR T cells were responsive to CD19+ tumor cells with antitumor activities that induced complete tumor remission in NALM6 tumor-bearing mice while significantly reducing TCR alloreactivity and GvHD development. Single CAR signaling induced the similar T cell signaling signatures in TCR-disrupted CAR T cells and control CAR T cells. In contrast, TCR disruption inhibited T cell signaling/protein phosphorylation compared with the control CAR T cells during dual CAR/TCR signaling. This non-viral SB transposon-CRISPR-Cas9 combination strategy serves as an alternative for generating next-generation CD19-specific CAR T while reducing GvHD risk and easing potential manufacturing constraints intrinsic to viral vectors.

Combined PD-L1 and TIM3 blockade improves expansion of fit human CD8+ antigen-specific T cells for adoptive immunotherapy

Antigen-specific T cell expansion ex vivo followed by adoptive transfer enables targeting of a multitude of microbial and cancer antigens. However, clinical-scale T cell expansion from rare precursors requires repeated stimulation, which may lead to T cell dysfunction and limited therapeutic potential. We used a clinically compliant protocol to expand Epstein-Barr virus (EBV) and Wilms tumor 1 (WT1) antigen-specific CD8⁺ T cells, and leveraged T cell exhaustion-associated inhibitory receptor blockade to improve T cell expansion. Several inhibitory receptors were expressed early by ex vivo-expanded antigen-specific CD8⁺ T cells, including PD-1 and TIM3, with co-expression matching evidence of T cell dysfunction as the cultures progressed. Introduction of anti-PD-L1 and anti-TIM3 blockade in combination (but not individually) to the culture led to markedly improved antigen-specific T cell expansion without inducing T cell dysfunction. Single-cell RNA sequencing (RNA-seq) and T cell receptor (TCR) repertoire profiling revealed that double blockade does not impart specific transcriptional programs in T cells or alterations in TCR repertoires. However, combined blockade may affect gene expression in a minority of clonotypes in a donor-specific fashion. We conclude that antigen-specific CD8⁺ T cell manufacturing can be improved by using TIM3 and PD-L1/PD-1 axis blockade in combination. This approach is readily applicable to several adoptive immunotherapy strategies.

Antifungal immunity mediated by C-type lectin receptors may be a novel target in immunotherapy for urothelial bladder cancer

Immunotherapies, such as immune-checkpoint blockade and adoptive T-cell therapy, offer novel treatment options with good efficacy for patients with urothelial bladder cancer. However, heterogeneity and therapeutic resistance have limited the use of immunotherapy. Further research into immune-regulatory mechanisms in bladder cancer is urgently required. Emerging evidence demonstrates that the commensal microbiota and its interactions with host immunity play pivotal roles in a variety of physiological and pathological processes, including in cancer. The gut microbiota has been identified as a potentially effective target of treatment that can be synergized with immunotherapy. The urothelial tract is also a key site for multiple microbes, although the immune-regulatory role of the urinary microbiome in the process of carcinogenesis of bladder cancer remains to be elucidated. We performed a comprehensive analysis of the expression and biological functions of C-type lectin receptors (CLRs), which have been recognized as innate pathogen-associated receptors for fungal microbiota, in bladder cancer. In line with previous research on fungal colonization of the urothelial tract, we found that CLRs, including Dectin-1, Dectin-2, Dectin-3, and macrophage-inducible Ca²⁺-dependent lectin receptor (Mincle), had a significant association with immune infiltration in bladder cancer. Multiple innate and adaptive pathways are positively correlated with the upregulation of CLRs. In addition, we found a significant correlation between the expression of CLRs and a range of immune-checkpoint proteins in bladder cancer. Based on previous studies and our findings, we hypothesize that the urinary mycobiome plays a key role in the pathogenesis of bladder cancer and call for more research on CLR-mediated anti-fungal immunity against bladder cancer as a novel target for immunotherapy in urothelial bladder cancer.

Apoptotic vesicles ameliorate lupus and arthritis via phosphatidylserine-mediated modulation of T cell receptor signaling

Mesenchymal stem cells (MSCs) influence T cells in health, disease and therapy through messengers of intercellular communication including extracellular vesicles (EVs). Apoptosis is a mode of cell death that tends to promote immune tolerance, and a large number of apoptotic vesicles (apoVs) are generated from MSCs during apoptosis. In an effort to characterize these apoVs and explore their immunomodulatory potential, here we show that after replenishing them systemically, the apoV deficiency in Fas mutant mice and pathological lymphoproliferation were rescued, leading to the amelioration of inflammation and lupus activity. ApoVs directly interacted with CD4⁺ T cells and inhibited CD25 expression and IL-2 production in a dose-dependent manner. A broad range of Th1/2/17 subsets and cytokines including IFNγ, IL17A and IL-10 were suppressed while Foxp3⁺ cells were maintained. Mechanistically, exposed phosphatidylserine (PtdSer/PS) on apoVs mediated the interaction with T cells to disrupt proximal T cell receptor signaling transduction. Remarkably, administration of apoVs prevented Th17 differentiation and memory formation, and ameliorated inflammation and joint erosion in murine arthritis. Collectively, our findings unveil a previously unrecognized crosstalk between MSC apoVs and CD4⁺ T cells and suggest a promising therapeutic use of apoVs for autoimmune diseases.

Expression Level and Significance of Tim-3 in CD4+ T Lymphocytes in Peripheral Blood of Patients with Coronary Heart Disease

OBJECTIVE

To investigate the expression level and significance of T cell immunoglobulin and mucin-domain containing molecules-3 (Tim-3) and interleukin-7 (IL-7) in CD4+ T lymphocytes in peripheral blood of patients with coronary heart disease (CHD).

METHODS

75 patients with CHD treated at our hospital were selected and classified as mild group (25 cases), moderate group (25 cases) and severe group (25 cases), according to the severity of illness. Twenty-five healthy volunteers who underwent a physical examination at our hospital during the same period were selected as the control group. The expression level of Tim-3 in CD4+ T lymphocytes in peripheral blood of patients in four groups was detected by flow cytometry and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). The expression level of IL-7 in peripheral blood serum was measured by enzymelinked immunosorbent assay (ELISA). Correlation analyses of Tim-3 and IL-7, Tim-3 and disease severity and IL-7 and disease severity were performed, respectively.

RESULTS

Flow cytometry and qRT-PCR demonstrated that the expression of Tim-3 in CD4+ T lymphocytes in peripheral blood of patients with CHD increased with the aggravation of the disease. ELISA showed that the tendency of IL-7 expression in peripheral blood serum was consistent with the expression of Tim-3, and the expression of Tim-3 had a positive correlation with IL-7. The expression levels of both Tim-3 and IL-7 were positively correlated with the Gensini score.

CONCLUSION

The expression of Tim-3 and IL-7 in peripheral blood of patients with CHD was upregulated and increased with the aggravation of CHD.

Phosphatidylserine binding directly regulates TIM-3 function

Co-signaling receptors for the T cell receptor (TCR) are important therapeutic targets, with blockade of co-inhibitory receptors such as PD-1 now central in immuno-oncology. Advancing additional therapeutic immune modulation approaches requires understanding ligand regulation of other co-signaling receptors. One poorly understood potential therapeutic target is TIM-3 (T cell immunoglobulin and mucin domain containing-3). Which of TIM-3's several proposed regulatory ligands is/are relevant for signaling is unclear, and different studies have reported TIM-3 as a co-inhibitory or co-stimulatory receptor in T cells. Here, we show that TIM-3 promotes NF-κB signaling and IL-2 secretion following TCR stimulation in Jurkat cells, and that this activity is regulated by binding to phosphatidylserine (PS). TIM-3 signaling is stimulated by PS exposed constitutively in cultured Jurkat cells, and can be blocked by mutating the PS-binding site or by occluding this site with an antibody. We also find that TIM-3 signaling alters CD28 phosphorylation. Our findings clarify the importance of PS as a functional TIM-3 ligand, and may inform the future exploitation of TIM-3 as a therapeutic target.

Highly proliferative and functional PD-1+ and TIM-3+ T cells are transiently increased in multiple myeloma following autologous hematopoietic stem cell transplantation

The aim of our prospective study was to assess recovery dynamics and functional characteristics of PD-1⁺ and TIM-3⁺ T cells in multiple myeloma (MM) patients following high-dose chemotherapy (HDCT) with autologous hematopoietic stem cell transplantation (AHSCT). Peripheral blood, autograft and bone marrow samples were obtained from 46 MM patients before conditioning, at the engraftment, following six and 12 months post-transplant. Frequencies of CD4⁺ and CD8⁺ T cells expressing PD-1 and TIM-3 and intracellular expression of Ki-67 and Granzyme B were evaluated. Counts of PD-1⁺ and TIM-3⁺ T cells at the engraftment were significantly higher comparing with the levels before HDCT and 6-12 months following AHSCT. The post-transplant increase in the studied subsets was due to a temporary enhancement in proliferation activity. The cytotoxic potential of PD-1- and TIM-3-expressing CD8⁺ T cells was higher at the engraftment comparing with the pre-transplant and remained at the same level for at least 12 months. The increase in CD4⁺PD-1⁺ and CD8⁺TIM-3⁺ T cells at the engraftment was associated with higher absolute counts of their reinfused counterparts. Circulating PD-1⁺ CD8⁺ and TIM-3⁺ CD4⁺ T cells were increased in patients after post-transplant relapse comparing with the ones in remission. Homeostatic proliferation plays a key role in the upregulation of inhibitory checkpoint receptors on functional T cells under lymphopenic conditions. In this regard, it is difficult to predict both the efficacy and adverse reactions of therapy with checkpoint inhibitors on the course of MM after HDCT with AHSCT. Précis. Homeostatic proliferation plays apparently a key role in the upregulation of PD-1 and TIM-3 on functional T cells after AHSCT and appears to be a normal physiological process, contrary to relapse-associated increase in PD-1⁺ and TIM-3⁺ T cells.

An engineered IL-2 partial agonist promotes CD8+ T cell stemness

Adoptive transfer of antigen-specific T cells represents a major advance in cancer immunotherapy, with robust clinical outcomes in some patients¹. Both the number of transferred T cells and their differentiation state are critical determinants of effective responses^2,3. T cells can be expanded with T cell receptor (TCR)-mediated stimulation and interleukin-2, but this can lead to differentiation into effector T cells^4,5 and lower therapeutic efficacy⁶, whereas maintenance of a more stem-cell-like state before adoptive transfer is beneficial⁷. Here we show that H9T, an engineered interleukin-2 partial agonist, promotes the expansion of CD8⁺ T cells without driving terminal differentiation. H9T led to altered STAT5 signalling and mediated distinctive downstream transcriptional, epigenetic and metabolic programs. In addition, H9T treatment sustained the expression of T cell transcription factor 1 (TCF-1) and promoted mitochondrial fitness, thereby facilitating the maintenance of a stem-cell-like state. Moreover, TCR-transgenic and chimeric antigen receptor-modified CD8⁺ T cells that were expanded with H9T showed robust anti-tumour activity in vivo in mouse models of melanoma and acute lymphoblastic leukaemia. Thus, engineering cytokine variants with distinctive properties is a promising strategy for creating new molecules with translational potential.

Endogenous TCR promotes in vivo persistence of CD19-CAR-T cells compared to a CRISPR/Cas9-mediated TCR knockout CAR

Anti-CD19 chimeric antigen receptor (CAR) T cells showed significant antileukemic activity in B-precursor acute lymphoblastic leukemia (ALL). Allogeneic, HLA-mismatched off-the-shelf third-party donors may offer ideal fitness of the effector cells, but carry the risk of graft-versus-host disease. Knockout (KO) of the endogenous T-cell receptor (TCR) in CD19-CAR-T cells may be a promising solution. Here, we induced a CRISPR/Cas9-mediated KO of the TCRβ chain in combination with a second-generation retroviral CAR transduction including a 4-1BB costimulatory domain in primary T cells. This tandem engineering led to a highly functional population of TCR-KO-CAR-T cells with strong activation (CD25, interferon γ), proliferation, and specific killing upon CD19 target recognition. TCR-KO-CAR-T cells had a balanced phenotype of central memory and effector memory T cells. KO of the endogenous TCR in T cells strongly ablated alloreactivity in comparison with TCR-expressing T cells. In a patient-derived xenograft model of childhood ALL, TCR-KO-CAR-T cells clearly controlled CD19+ leukemia burden and improved survival in vivo. However, coexpression of endogenous TCR plus CAR led to superior persistence of T cells and significantly prolonged leukemia control in vivo, confirmed by a second in vivo model using the leukemia cell line NALM6. These results point toward an essential role of the endogenous TCR for longevity of the response at the price of alloreactivity. In conclusion, anti-CD19 CAR T cells with a CRISPR/Cas9-mediated TCR-KO are promising candidates for nonmatched third-party adoptive T-cell transfer with high antileukemic functionality in the absence of alloreactivity, but long-term persistence in vivo is better in the presence of the endogenous TCR.

IL-2 regulates tumor-reactive CD8+ T cell exhaustion by activating the aryl hydrocarbon receptor

CD8⁺ T cell exhaustion dampens antitumor immunity. Although several transcription factors have been identified that regulate T cell exhaustion, the molecular mechanisms by which CD8⁺ T cells are triggered to enter an exhausted state remain unclear. Here, we show that interleukin-2 (IL-2) acts as an environmental cue to induce CD8⁺ T cell exhaustion within tumor microenvironments. We find that a continuously high level of IL-2 leads to the persistent activation of STAT5 in CD8⁺ T cells, which in turn induces strong expression of tryptophan hydroxylase 1, thus catalyzing the conversion to tryptophan to 5-hydroxytryptophan (5-HTP). 5-HTP subsequently activates AhR nuclear translocation, causing a coordinated upregulation of inhibitory receptors and downregulation of cytokine and effector-molecule production, thereby rendering T cells dysfunctional in the tumor microenvironment. This molecular pathway is not only present in mouse tumor models but is also observed in people with cancer, identifying IL-2 as a novel inducer of T cell exhaustion.

Potential therapeutic targets in the tumor microenvironment of hepatocellular carcinoma: reversing the protumor effect of tumor-associated macrophages

In hepatocellular carcinoma patients, due to the microenvironmental specificity of liver, the tumor microenvironment exhibits high immunosuppression and drug resistance, resulting in excessive or insufficient responses to immunotherapy. The dynamic interactions between tumor cells and immune modulators in the TME significantly impact the occurrence and development of tumors, efficacy, and drug resistance, which can create a much more positive response to immunotherapy. Moreover, with the wide application of single-cell sequencing technology in the TME, increasing evidence shows an interaction network among cells. Sequencing results suggest that specific tumor-associated macrophages are a hub node, connecting different cell populations in the cell interaction network, and can could regulate tumor generation and antitumor immunity. This review focused on therapeutic targets that could be targeted to remodel the tumor microenvironment and reprogram the tumor-associated macrophage phenotype in hepatocellular carcinoma patients, thereby improving immunotherapeutic efficacy.

Evaluation of Production Protocols for the Generation of NY-ESO-1-Specific T Cells

NY-ESO-1-specific T cells have shown promising activity in the treatment of soft tissue sarcoma (STS). However, standardized protocols for their generation are limited. Particularly, cost-effectiveness considerations of cell production protocols are of importance for conducting clinical studies. In this study, two different NY-ESO-1-specific T cell production protocols were compared. Major differences between protocols 1 and 2 include culture medium, interleukin-2 and retronectin concentrations, T cell activation strategy, and the transduction process. NY-ESO-1-specific T cells generated according to the two protocols were investigated for differences in cell viability, transduction efficiency, T cell expansion, immunophenotype as well as functionality. NY-ESO-1-specific T cells showed similar viability and transduction efficiency between both protocols. Protocol 1 generated higher absolute numbers of NY-ESO-1-specific T cells. However, there was no difference in absolute numbers of NY-ESO-1-specific T cell subsets with less-differentiated phenotypes accounting for efficient in vivo expansion and engraftment. Furthermore, cells generated according to protocol 1 displayed higher capacity of TNF-α generation, but lower cytotoxic capacities. Overall, both protocols provided functional NY-ESO-1-specific T cells. However, compared to protocol 1, protocol 2 is advantageous in terms of cost-effectiveness. Cell production protocols should be designed diligently to achieve a cost-effective cellular product for further clinical evaluation.

Acute Conditioning of Antigen-Expanded CD8+ T Cells via the GSK3β-mTORC Axis Differentially Dictates Their Immediate and Distal Responses after Antigen Rechallenge

Simple Summary

Expanded, antigen-experienced CD8⁺ T cells are utilized in immunotherapy to treat infections and cancers. Antigen rechallenge of these cells leads to their re-expansion. The effector functions of re-expanded CD8⁺ T cells are critical for their therapeutic efficacy. We found that acute conditioning of the cells, before antigen rechallenge, impacts their effector function after re-expansion. Our data showed that acute pharmacological modulation of the GSK3β-mTORC axis with TWS119 or rapamycin, but not Torin1, before antigen rechallenge promotes the effector functions of re-expanded CD8⁺ T cells. These findings suggest that acute conditioning of the GSK3β-mTORC axis in expanded CD8⁺ T cells, before antigen rechallenge, can promote the therapeutic performance of re-expanded CD8⁺ T cells.

Abstract

CD8⁺ T cells protect against tumors and intracellular pathogens. The inflammatory cytokines IL-2, IL-15, and IL-7 are necessary for their expansion. However, elevated serum levels of these cytokines are often associated with cancer, poorer prognosis of cancer patients, and exhaustion of antigen-expanded CD8⁺ T cells. The impact of acute conditioning of antigen-expanded CD8⁺ T cells with these cytokines is unknown. Here, we generated antigen-expanded CD8⁺ T cells using dendritic cells and PC-3 cells. The cells were acutely (18–24 h) conditioned with IL-2 and either the GSK3β inhibitor TWS119, the mTORC1 inhibitor rapamycin, or the mTORC1/2 inhibitor Torin1, then their immediate and post-re-expansion (distal) cytokine responses after antigen rechallenge were evaluated. We found that acute IL-2 conditioning upregulated the immediate antigen-induced cytokine response of the tested cells. Following their re-expansion, however, the cells showed a decreased cytokine response. These IL-2 conditioning-mediated impacts were counteracted with TWS119 or rapamycin but not with Torin1. Our data revealed that the acute conditioning of antigen-expanded CD8⁺ T cells with IL-2 modulates the GSK3β-mTORC signaling axis. This modulation differentially affected the immediate and distal cytokine responses of the cells. The acute targeting of this signaling axis could, therefore, represent a novel strategy for the modulation of antigen-expanded CD8⁺ T cells.

Ovarian granulosa cell tumor characterization identifies FOXL2 as an immunotherapeutic target

Granulosa cell tumors (GCT) are rare ovarian malignancies. Due to the lack of effective treatment in late relapse, there is a clear unmet need for novel therapies. Forkhead Box L2 (FOXL2) is a protein mainly expressed in granulosa cells (GC) and therefore is a rational therapeutic target. Since we identified tumor infiltrating lymphocytes (TILs) as the main immune population within GCT, TILs from 11 GCT patients were expanded, and their phenotypes were interrogated to determine that T cells acquired late antigen-experienced phenotypes and lower levels of PD1 expression. Importantly, TILs maintained their functionality after ex vivo expansion as they vigorously reacted against autologous tumors (100% of patients) and against FOXL2 peptides (57.1% of patients). To validate the relevance of FOXL2 as a target for immune therapy, we developed a plasmid DNA vaccine (FoxL2–tetanus toxin; FoxL2-TT) by fusing Foxl2 cDNA with the immune-enhancing domain of TT. Mice immunization with FoxL2-TT controlled growth of FOXL2-expressing ovarian (BR5) and breast (4T1) cancers in a T cell–mediated manner. Combination of anti–PD-L1 with FoxL2-TT vaccination further reduced tumor progression and improved mouse survival without affecting the female reproductive system and pregnancy. Together, our results suggest that FOXL2 immune targeting can produce substantial long-term clinical benefits. Our study can serve as a foundation for trials testing immunotherapeutic approaches in patients with ovarian GCT.

FOXL2 may serve as a immunotherapeutic target for tumor infiltrating lymphocytes in ovarian granulosa cell tumors.

IL-15 in the Combination Immunotherapy of Cancer

We completed clinical trials of rhIL-15 by bolus, subcutaneous, and continuous intravenous infusions (CIV). IL-15 administered by CIV at 2 mcg/kg/day yielded a 38-fold increase in 10- day number of circulating NK cells, a 358-fold increase in CD56^bright NK cells and a 5.8-fold increase in CD8 T cells. However, IL-15 preparations administered as monotherapy were ineffective, due to actions of immunological checkpoints and due to the lack of tumor specific targeting by NK cells. To circumvent checkpoints, trials of IL-15 in combination with other anticancer agents were initiated. Tumor-bearing mice receiving IL-15 with antibodies to CTLA-4 and PD-L1 manifested marked prolongation of survival compared to mice receiving IL-15 with either agent alone. In translation, a phase I trial was initiated involving IL-15 (rhIL-15), nivolumab and ipilimumab in patients with malignancy (NCT03388632). In rhesus macaques CIV IL-15 at 20 μg/kg/day for 10 days led to an 80-fold increase in number of circulating effector memory CD8 T cells. However, administration of γc cytokines such as IL-15 led to paralysis/depression of CD4 T-cells that was mediated through transient expression of SOCS3 that inhibited the STAT5 signaling pathway. This lost CD4 helper role could be restored alternatively by CD40 agonists. In the TRAMP-C2 prostate tumor model the combination of IL-15 with agonistic anti-CD40 produced additive effects in terms of numbers of TRAMP-C2 tumor specific Spas/SCNC/9H tetramer positive CD8 T cells expressed and tumor responses. A clinical trial is being initiated for patients with cancer using an intralesional anti-CD40 in combination with CIV rhIL-15. To translate IL-15-mediated increases in NK cells, we investigated combination therapy of IL-15 with anticancer monoclonal antibodies including rituximab in mouse models of EL-4 lymphoma transfected with human CD20 and with alemtuzumab (CAMPATH-1H) in a xenograft model of adult T cell leukemia (ATL). IL-15 enhanced the ADCC and therapeutic efficacy of both antibodies. These results provided the scientific basis for trials of IL-15 combined with alemtuzumab (anti-CD52) for patients with ATL (NCT02689453), with obinutuzumab (anti-CD20) for patients with CLL (NCT03759184), and with avelumab (anti-PD-L1) in patients with T-cell lymphoma (NCT03905135) and renal cancer (NCT04150562). In the first trial, there was elimination of circulating ATL and CLL leukemic cells in select patients.

Human CD8+CD28- T suppressor cells expanded by common gamma chain (γc) cytokines retain steady allospecific suppressive capacity in vivo

Background

CD8⁺CD28⁻ T suppressor (Ts) cells play critical role in transplant tolerance. Our previous study has generated CD8⁺CD28⁻ Ts cells in vitro which exert robust allospecific suppressive capacity in vitro.

Results

CD8⁺CD28⁻ Ts cells were expanded by stimulating human CD8⁺ T cells with allogeneic antigen presenting cells in the presence of the common gamma chain cytokines IL-2, IL-7 and IL-15 in vitro, and were further verified in vitro through day 7 to 11 for their persistency of the allospecific suppressive capacity. When CD8⁺CD28⁻ Ts cells were adoptively transferred into NOG mice, their capacity to inhibit CD4⁺ T cell proliferation in allospecific manner remained potent on 11 days after their injection. The mechanisms for expansion of CD8⁺CD28⁻ Ts cells by the common gamma chain cytokines were investigated. These included promoting CD8⁺CD28⁻ T cells proliferation, converting CD8⁺CD28⁺ T cells to CD8⁺CD28⁻ T cells and decreasing CD8⁺CD28⁻ T cell death. Furthermore, the expanded CD8⁺CD28⁻ Ts cells showed upregulation of the co-inhibitory molecule Tim-3 and down-regulation of the cytotoxic molecule granzyme B.

Conclusions

In summary, these results demonstrated that the in vitro-expanded human CD8⁺CD28⁻ T cells retained potent allospecific suppressive capacity in vivo and depicted multiple mechanisms for the expansion of Ts cells, which might promote further bench to clinic research.

Tim-3: A co-receptor with diverse roles in T cell exhaustion and tolerance

T cell inhibitory co-receptors play a crucial role in maintaining the balance between physiologic immune responses and maladaptive ones. T cell immunoglobulin and mucin domain-containing-3 (Tim-3) is a unique inhibitory co-receptor in that its expression is chiefly restricted to interferon (IFN)γ-producing CD4⁺ and CD8⁺ T cells. Early reports firmly established its importance in maintaining peripheral tolerance in transplantation and autoimmunity. However, it has become increasingly clear that Tim-3 expression on T cells, together with other check-point molecules, in chronic infections and cancers can hinder productive immune responses. In this review, we outline what is currently known about the regulation of Tim-3 expression, its ligands and signaling. We discuss both its salutary and deleterious function in immune disorders, as well as the T cell-extrinsic and -intrinsic factors that regulate its function.

Leukemia-induced dysfunctional TIM-3+CD4+ bone marrow T cells increase risk of relapse in pediatric B-precursor ALL patients

Interaction of malignancies with tissue-specific immune cells has gained interest for prognosis and intervention of emerging immunotherapies. We analyzed bone marrow T cells (bmT) as tumor-infiltrating lymphocytes in pediatric precursor-B cell acute lymphoblastic leukemia (ALL). Based on data from 100 patients, we show that ALL is associated with late-stage CD4⁺ phenotype and loss of early CD8⁺ T cells. The inhibitory exhaustion marker TIM-3 on CD4⁺ bmT increased relapse risk (RFS = 94.6/70.3%) confirmed by multivariate analysis. The hazard ratio of TIM-3 expression nearly reached the hazard ratio of MRD (7.1 vs. 8.0) indicating that patients with a high frequency of TIM-3⁺CD4⁺ bone marrow T cells at initial diagnosis have a 7.1-fold increased risk to develop ALL relapse. Comparison of wild type primary T cells to CRISPR/Cas9-mediated TIM-3 knockout and TIM-3 overexpression confirmed the negative effect of TIM-3 on T cell responses against ALL. TIM-3⁺CD4⁺ bmT are increased in ALL overexpressing CD200, that leads to dysfunctional antileukemic T cell responses. In conclusion, TIM-3-mediated interaction between bmT and leukemia cells is shown as a strong risk factor for relapse in pediatric B-lineage ALL. CD200/TIM-3-signaling, rather than PD-1/PD-L1, is uncovered as a mechanism of T cell dysfunction in ALL with major implication for future immunotherapies.

A Pilot Trial of the Combination of Transgenic NY-ESO-1-reactive Adoptive Cellular Therapy with Dendritic Cell Vaccination with or without Ipilimumab

PURPOSE

Transgenic adoptive cell therapy (ACT) targeting the tumor antigen NY-ESO-1 can be effective for the treatment of sarcoma and melanoma. Preclinical models have shown that this therapy can be improved with the addition of dendritic cell (DC) vaccination and immune checkpoint blockade. We studied the safety, feasibility, and antitumor efficacy of transgenic ACT with DC vaccination, with and without CTLA-4 blockade with ipilimumab.

PATIENTS AND METHODS

Freshly prepared autologous NY-ESO-1-specific T-cell receptor (TCR) transgenic lymphocytes were adoptively transferred together with NY-ESO-1 peptide-pulsed DC vaccination in HLA-A2.1-positive subjects alone (ESO, NCT02070406) or with ipilimumab (INY, NCT01697527) in patients with advanced sarcoma or melanoma.

RESULTS

Six patients were enrolled in the ESO cohort, and four were enrolled in the INY cohort. Four out of six patients treated per ESO (66%), and two out of four patients treated per INY (50%) displayed evidence of tumor regression. Peripheral blood reconstitution with NY-ESO-1-specific T cells peaked within 2 weeks of ACT, indicating rapid in vivo expansion. Tracking of transgenic T cells to the tumor sites was demonstrated in on-treatment biopsies via TCR sequencing. Multiparametric mass cytometry of transgenic cells demonstrated shifting of transgenic cells from memory phenotypes to more terminally differentiated effector phenotypes over time.

CONCLUSIONS

ACT of fresh NY-ESO-1 transgenic T cells prepared via a short ex vivo protocol and given with DC vaccination, with or without ipilimumab, is feasible and results in transient antitumor activity, with no apparent clinical benefit of the addition of ipilimumab. Improvements are needed to maintain tumor responses.

Association between Interleukin-21 and Interleukin-21 receptor gene polymorphisms with susceptibility to chronic hepatitis B virus infection and HBV spontaneous clearance in Iranian population

Hepatitis B virus (HBV) infection is a major public health concern due to the infection often leads to chronic infection, liver cirrhosis and also liver cancer. The host immune response to HBV infection and also genetic background play significant role in outcome of infection. Single nucleotide polymorphisms (SNPs) are the most important kind of variation in genetic sequences that caused by point mutations. As cytokines have major roles in viral infections, it seems that cytokine gene polymorphisms are independently associated with response to viral infections. Interleukin 21 (IL-21) plays an influential role in both innate and adaptive immune responses. Its specific receptor, IL-21R, produced and located on the surface of T, B and natural killer (NK) cells and is critical for the proliferation and differentiation of these immune effector cells. Many studies confirmed that the IL-21 involved in response to viral infections. We aimed to investigate the association of G/T IL-21 (rs2055979) and C/T IL-21R (rs3093390) gene polymorphisms with chronic hepatitis B virus infection and HBV spontaneous clearance in Iranian population.

METHODS

In this study, blood samples were gathered from 320 patients with chronic HBV and 310 healthy controls and also 120 HBV spontaneous clearance individuals. Following genomic DNA extraction, genotypes of the selected SNPs determined by PCR and restriction fragment length polymorphism (RFLP) method. The results were analyzed by SPSS software using Chi-square, Logistic Regression, ANOVA and Independent Samples t-Test.

RESULTS

According to our results, in IL-21R (rs3093390 C/T) gene polymorphism, allele frequency of T is statistically different in the HBV spontaneous clearance group compared to chronic HBV cases. But there is no significant difference between G/T IL-21 (rs2055979) and C/T IL-21R (rs3093390) genotypes distribution in three groups. Also we found that higher serum aspartate transaminase (AST) level in HBV spontaneous clearance group is significantly associated with TT genotype of IL-21 (rs2055979) compared to GG genotype (P value = 0.006).

DISCUSSION

Our results showed that T allele frequency in IL-21R (rs3093390 C/T) gene polymorphism could consider as a host genetic factor for HBV spontaneous clearance. Probably we can serve it as a potential prognostic genetic marker for spontaneous clearance of HBV infection.

Regulation of TIM-3 expression in a human T cell line by tumor-conditioned media and cyclic AMP-dependent signaling

T cell immunoglobulin and mucin domain-3 (TIM-3) expression increases in exhausted T cells, which inhibits T cell function. TIM-3 expression is supposedly up-regulated in tumor-bearing individuals via chronic antigenic stimulation of T cells. Considering the immunosuppressive nature of the tumor microenvironment, we investigated whether tumor-secreted molecules might enhance TIM-3 expression in Jurkat T cells. We observed that TIM-3 expression was increased by the activation of prostaglandin (PG) E₂ and cyclic AMP (cAMP) signaling pathways. Adenylate cyclase activation led to protein kinase A (PKA)-dependent upregulation of the TIM-3 minimal promoter region and of upstream conserved non-coding sequences. TIM-3 expression in Jurkat T cells was increased by the exposure to breast tumor cell-conditioned media partially through the interaction between PGE₂ and its receptor, EP4. Our results propose that tumor-secreted molecules such as PGE₂, which activates PKA and EPAC, may regulate TIM-3 expression in T cells.

Tim-3 expression and its role in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common tumors in the world, and its mortality is still on the rise. Limited treatments and low chemotherapy sensitivity of HCC make new therapeutic strategies urgently needed. With the rise of immune checkpoint blockade, anti-CTLA-4 antibodies and anti-PD-1 antibodies have shown therapeutic effects in various tumors. T cell immunoglobulin mucin-3 (Tim-3), a newly discovered immune checkpoint molecule, plays a major role in the development of HCC. Tim-3 can be used to evaluate the prognosis and therapeutic effects in HCC, and Tim-3 intervention has shown anti-tumor effects in preclinical experiments. This review summarizes findings regarding Tim-3 and HCC in recent years and discusses the rationale of Tim-3 as a therapeutic target for HCC.

Expression of the Inhibitory Receptor TIGIT Is Up-Regulated Specifically on NK Cells With CD226 Activating Receptor From HIV-Infected Individuals

Natural killer (NK) cells are important for maintenance of innate immune system stability and serve as a first line of defense against tumors and virus infections; they can act either directly or indirectly and are regulated via co-operation between inhibitory and stimulatory surface receptors. The recently reported inhibitory receptor, TIGIT, can be expressed on the NK cell surface; however, the expression level and function of TIGIT on NK cells during HIV infection is unknown. In this study, for the first time, we investigated the expression and function of TIGIT in NK cells from HIV-infected individuals. Our data demonstrate that the level of TIGIT is higher on NK cells from patients infected with human immunodeficiency virus (HIV) compared with HIV-negative healthy controls. TIGIT expression is inversely correlated with CD4⁺ T cell counts and positively correlated with plasma viral loads. Additionally, levels of the TIGIT ligand, CD155, were higher on CD4⁺ T cells from HIV-infected individuals compared with those from healthy controls; however, there was no difference in the level of the activating receptor, CD226, which recognizes the same ligands as TIGIT. Furthermore, TIGIT was found to specifically up-regulated on CD226⁺ NK cells in HIV-infected individuals, and either rIL-10, or rIL-12 + rIL-15, could induce TIGIT expression on these cells. In addition, high TIGIT expression inhibited the production of interferon-gamma (IFN-γ) by NK cells, while TIGIT inhibition restored IFN-γ production. Overall, these results highlight the important role of TIGIT in NK cell function and suggest a potential new avenue for the development of therapeutic strategies toward a functional cure for HIV.

Ex vivo expanded tumour-infiltrating lymphocytes from ovarian cancer patients release anti-tumour cytokines in response to autologous primary ovarian cancer cells

Epithelial ovarian cancer (EOC) is the leading cause of gynaecological cancer-related death in Europe. Although most patients achieve an initial complete response with first-line treatment, recurrence occurs in more than 80% of cases. Thus, there is a clear unmet need for novel second-line treatments. EOC is frequently infiltrated with T lymphocytes, the presence of which has been shown to be associated with improved clinical outcomes. Adoptive T-cell therapy (ACT) using ex vivo-expanded tumour-infiltrating lymphocytes (TILs) has shown remarkable efficacy in other immunogenic tumours, and may represent a promising therapeutic strategy for EOC. In this preclinical study, we investigated the efficacy of using anti-CD3/anti-CD28 magnetic beads and IL-2 to expand TILs from freshly resected ovarian tumours. TILs were expanded for up to 3 weeks, and then subjected to a rapid-expansion protocol (REP) using irradiated feeder cells. Tumours were collected from 45 patients with EOC and TILs were successfully expanded from 89.7% of biopsies. Expanded CD4⁺ and CD8⁺ subsets demonstrated features associated with memory phenotypes, and had significantly higher expression of key activation and functional markers than unexpanded TILs. Expanded TILs produced anti-tumour cytokines when co-cultured with autologous tumour cells, inferring tumour cytotoxicity. Our findings demonstrate that it is possible to re-activate and expand tumour-reactive T cells from ovarian tumours. This presents a promising immunotherapy that could be used sequentially or in combination with current therapeutic strategies.

Immune checkpoint receptors: homeostatic regulators of immunity

Alcoholic liver disease (ALD) is an escalating global problem accounting for more than 3 million deaths annually. Bacterial infections are diagnosed in 25-47% of hospitalized patients with cirrhosis and represent the most important trigger for acute decompensation, multi-organ failure, septic shock and death. Current guidelines recommend intensive antibiotic therapy, but this has led to the emergence of multi-drug resistant bacteria, which are associated with increased morbidity and mortality rates. As such, there is a pressing need to explore new paradigms for anti-infective therapy and host-directed immunomodulatory therapies are a promising approach. Paradoxically, cirrhotic patients are characterised by heightened immune activity and exacerbated inflammatory processes but are unable to contend with bacterial infection, demonstrating that whilst immune effector cells are primed, their antibacterial effector functions are switched-off, reflecting a skewed homeostatic balance between anti-pathogen immunity and host-induced immunopathology. Preservation of this equilibrium physiologically is maintained by multiple immune-regulatory checkpoints and these feedback receptors serve as pivotal regulators of the host immunity. Checkpoint receptor blockade is proving to be effective at rescuing deranged/exhausted immunity in pre-clinical studies for chronic viral infection and sepsis. This approach has also obtained FDA approval for restoring anti-tumor immunity, with improved response rates and good safety profiles. To date, no clinical studies have investigated checkpoint blockade in ALD, highlighting an area for development of host-targeted immunotherapeutic strategies in ALD, for which there are no current specific treatment options. This review aims at framing current knowledge on immune checkpoints and the possibility of their therapeutic utility in ALD-associated immune dysfunctions.

Alpha-lactose reverses liver injury via blockade of Tim-3-mediated CD8 apoptosis in sepsis

In sepsis, the liver plays a crucial role in regulating immune responses and is also a target organ for immune-related injury. Despite the critical function of CD8⁺ T cells against opportunistic viral infections, the CD8 immune response in the liver during sepsis remains elusive. Here we found that Tim-3 is highly up-regulated in liver CD8⁺ T cells in a mouse cecal ligation and puncture model and in peripheral blood CD8⁺ T cells of human patients with sepsis. The expression of Tim-3 in liver CD8⁺ T cells displayed a bi-phasic pattern and deletion of Tim-3 led to reduction of CD8⁺ T cell apoptosis. Administration of α-lactose, a molecule with a similar structure to galactin-9, reduced Tim-3 expression and liver injury in sepsis. Our results demonstrate that targeting Tim-3 to boost CD8⁺ T cell immune response may offer an improved outcome in patients with sepsis.

Multiparameter comparative analysis reveals differential impacts of various cytokines on CART cell phenotype and function ex vivo and in vivo

Exogenous cytokines are widely applied to enhance the anti-tumor ability of immune cells. However, systematic comparative studies of their effects on chimeric antigen receptor (CAR)-engineered T (CART) cells are lacking. In this study, CART cells targeting folate receptor-alpha were generated and expanded ex vivo in the presence of different cytokines (IL-2, IL-7, IL-15, IL-18, and IL-21), and their expansion, phenotype and cytotoxic capacity were evaluated, in vitro and in vivo. Moreover, the effect of the administration of these cytokines along with CART cells in vivo was also studied. IL-2, IL-7, and IL-15 favored the ex vivo expansion of CART cells compared to other cytokines or no cytokine treatment. IL-7 induced the highest proportion of memory stem cell-like CART cells in the final product, and IL-21 supported the expansion of CART cells with a younger phenotype, while IL-2 induced more differentiated CART cells. IL-2 and IL-15-exposed CART cells secreted more proinflammatory cytokines and presented stronger tumor-lysis ability in vitro. However, when tested in vivo, CART cells exposed to IL-2 ex vivo showed the least anti-tumor effect. In contrast, the administration of IL-15 and IL-21 in combination with CART cells in vivo increased their tumor killing capacity. According to our results, IL-7 and IL-15 show promise to promote ex vivo expansion of CART cells, while IL-15 and IL-21 seem better suited for in vivo administration after CART cell infusion. Collectively, these results may have a profound impact on the efficacy of CART cells in both hematologic and solid cancers.

TNFα blockade overcomes resistance to anti-PD-1 in experimental melanoma

Antibodies against programmed cell death-1 (PD-1) have considerably changed the treatment for melanoma. However, many patients do not display therapeutic response or eventually relapse. Moreover, patients treated with anti-PD-1 develop immune-related adverse events that can be cured with anti-tumor necrosis factor α (TNF) antibodies. Whether anti-TNF antibodies affect the anti-cancer immune response remains unknown. Our recent work has highlighted that TNFR1-dependent TNF signalling impairs the accumulation of CD8+ tumor-infiltrating T lymphocytes (CD8+ TILs) in mouse melanoma. Herein, our results indicate that TNF or TNFR1 blockade synergizes with anti-PD-1 on anti-cancer immune responses towards solid cancers. Mechanistically, TNF blockade prevents anti-PD-1-induced TIL cell death as well as PD-L1 and TIM-3 expression. TNF expression positively correlates with expression of PD-L1 and TIM-3 in human melanoma specimens. This study provides a strong rationale to develop a combination therapy based on the use of anti-PD-1 and anti-TNF in cancer patients.

Most melanoma patients do not respond to anti-PD1 therapy. Here, the authors show that TNFα blockade synergizes with anti-PD-1 by preventing anti-PD-1-induced CD8+ T cell death and TIM-3 expression on such cells.

Comprehensive Cross-Clade Characterization of Antibody-Mediated Recognition, Complement-Mediated Lysis, and Cell-Mediated Cytotoxicity of HIV-1 Envelope-Specific Antibodies toward Eradication of the HIV-1 Reservoir

Immunotherapy with passive administration of broadly neutralizing HIV-1 envelope-specific antibodies (bnAbs) in the setting of established infection in vivo has yielded mixed results. The contribution of different antibodies toward the direct elimination of infected cells is poorly understood. In this study, we determined the ability of 12 well-characterized anti-HIV-1 neutralizing antibodies to recognize and eliminate primary CD4 T cells infected with HIV-1 belonging to clades A, B, C, and D, via antibody-dependent complement-mediated lysis (ADCML) and antibody-dependent cell-mediated cytotoxicity (ADCC), in vitro We further tested unique combinations of these antibodies to determine the optimal antibody cocktails to be tested in future clinical trials. We report that antibody binding to infected CD4 T cells is highly variable and correlates with ADCML and ADCC processes. Particularly, antibodies targeting the envelope glycan shield (2G12) and V1/V2 site (PG9, PG16, and PGT145) are best at recognizing HIV-1-infected CD4 T cells. However, only PG9 and PG16 and their combinations with other bnAbs sufficiently induced the elimination of HIV-1-infected CD4 T cells by ADCML, ADCC, or both. Notably, CD4 binding site antibodies VRC01, 3BNC117, and NIH45-46 G54W did not exhibit recognition of infected cells and were unable to induce their killing. Future trials geared toward the development of a cure for HIV/AIDS should incorporate V1/V2 antibodies for maximal clearance of infected cells. With the use of only primary immune cells, we conducted a comprehensive cross-clade physiological analysis to aid the direction of antibodies as therapeutics toward the development of a cure for HIV/AIDS.IMPORTANCE Several antibodies capable of neutralizing the majority of circulating HIV-1 strains have been identified to date and have been shown to prevent infection in animal models. However, the use of combinations of such broadly neutralizing antibodies (bnAbs) for the treatment and eradication of HIV-1 in infected humans remains uncertain. In this study, we tested the ability of bnAbs to directly recognize and eliminate primary human CD4 T cells infected with diverse HIV-1 strains representative of the global epidemic by antibody-dependent pathways. We also tested several combinations of bnAbs in our assays in order to maximize the clearance of infected cells. We show that the ability of bnAbs to identify and kill infected cells is highly variable and that only a few of them are able to exert this function. Our data will help guide the formulation of bnAbs to test in future human trials aimed at the development of a cure.

Tim-3 and its role in regulating anti-tumor immunity

Immunotherapy is being increasingly recognized as a key therapeutic modality to treat cancer and represents one of the most exciting treatments for the disease. Fighting cancer with immunotherapy has revolutionized treatment for some patients and therapies targeting the immune checkpoint molecules such as CTLA-4 and PD-1 have achieved durable responses in melanoma, renal cancer, Hodgkin's diseases and lung cancer. However, the success rate of these treatments has been low and a large number of cancers, including colorectal cancer remain largely refractory to CTLA-4 and PD-1 blockade. This has provided impetus to identify other co-inhibitory receptors that could be exploited to enhance response rates of current immunotherapeutic agents and achieve responses to the cancers that are refectory to immunotherapy. Tim-3 is a co-inhibitory receptor that is expressed on IFN-g-producing T cells, FoxP3+ Treg cells and innate immune cells (macrophages and dendritic cells) where it has been shown to suppress their responses upon interaction with their ligand(s). Tim-3 has gained prominence as a potential candidate for cancer immunotherapy, where it has been shown that in vivo blockade of Tim-3 with other check-point inhibitors enhances anti-tumor immunity and suppresses tumor growth in several preclinical tumor models. This review discusses the recent findings on Tim-3, the role it plays in regulating immune responses in different cell types and the rationale for targeting Tim-3 for effective cancer immunotherapy.

TIM-3 plays a more important role than PD-1 in the functional impairments of cytotoxic T cells of malignant Schwannomas

Cancer immunotherapy using cytotoxic T cells demonstrates dramatic survival benefits in lymphomas, but its efficacy in solid tumors is limited. Here, we investigated the possibility of using cytotoxic T cells to treat malignant Schwannoma, a rare but aggressive nerve sheath tumor, by examining the native T-cell immunity in the host. We found that compared to CD8⁺ T cells from healthy controls or benign Schwannoma patients, the CD8⁺ T cells from malignant Schwannoma patients were present at normal frequencies but were substantially enriched with PD-1^-TIM-3⁺ and PD-1⁺TIM-3⁺ cells. Compared to the PD-1^-TIM-3^- CD8⁺ T cells, the PD-1^-TIM-3⁺ and PD-1⁺TIM-3⁺ CD8⁺ T cells presented significantly lower proliferation capacity, reduced interleukin 2 and interferon gamma expression, and/or dramatically decreased perforin and granzyme B secretion, indicating a whole-spectrum immunosuppression and reduced cytotoxicity. TIM-3 expression alone was associated with lower proliferation and less perforin and granzyme B secretion, whereas PD-1 expression alone was not associated with functional impairments, suggesting that TIM-3 expression was a better marker of exhausted CD8⁺ T cells. The expression of galectin 9, a TIM-3 ligand, in CD4⁺ Th cells was significantly elevated in malignant, but not benign, Schwannoma patients and were enriched in CD25⁺ Treg cells. Both the PD-1^-TIM-3⁺ and PD-1⁺TIM-3⁺ CD8⁺ T cells responded to Treg-mediated and galectin 9-mediated suppression, whereas the PD-1⁺TIM-3^- CD8⁺ T cells only responded to Treg-mediated suppression. In resected tumors, the malignant Schwannomas had more tumor-infiltrating CD4⁺ and CD8⁺ T cells than the benign Schwannomas, but a large fraction of these tumor-infiltrating CD4⁺ and CD8⁺ T cells expressed PD-1 and/or TIM-3, which indicated that their antitumor immunity was compromised. Together, our results suggested that PD-1 and TIM-3 blockade might be necessary in developing effective immunotherapeutic strategies in malignant Schwannoma, in which TIM-3 may play a more important role.

Selective Destruction of Interleukin 23-Induced Expansion of a Major Antigen-Specific γδ T-Cell Subset in Patients With Tuberculosis

A loss of antigen-specific T-cell responses due to defective cytokine signaling during infections has not been reported. We hypothesize that tuberculosis can destroy signaling effects of selective cytokine(s) and induce exhaustion of antigen-specific T cells. To test this hypothesis, mechanistic studies were performed to examine whether and how tuberculosis blocked interleukin 23 (IL-23) and interleukin 2 (IL-2) signaling effects on a major human γδ T-cell subpopulation, phosphoantigen HMBPP-specific Vγ2Vδ2 T cells. IL-23 and IL-2 significantly expanded HMBPP-stimulated Vγ2Vδ2 T cells from subjects with latent tuberculosis infection, and IL-2 synergized the effect of IL-23. IL-23-induced expansion of Vγ2Vδ2 T cells involved STAT3. Surprisingly, patients with tuberculosis exhibited a selective destruction of IL-23-induced expansion of these cells. The tuberculosis-driven destruction of IL-23 signaling coincided with decreases of expression and phosphorylation of STAT3. Interestingly, impairing of STAT3 was linked to marked increases in the microRNAs (miRNAs) hsa-miR-337-3p and hsa-miR-125b-5p in Vγ2Vδ2 T cells from patients with tuberculosis. Downregulation of hsa-miR-337-3p and hsa-miR-125b-5p by miRNA sponges improved IL-23-mediated expansion of Vγ2Vδ2 T cells and restored the ability of these cells to produce anti-tuberculosis cytokines. These results support our hypothesis that tuberculosis can selectively impair a cytokine effect while sparing another and can induce exhaustion of T cells in response to the respective cytokine.

Modulation of Tim-3 Expression by Antigen-Dependent and -Independent Factors on T Cells from Patients with Chronic Hepatitis B Virus Infection

T-cell immunoglobulin domain and mucin domain-containing molecule-3 (Tim-3) was up-regulated on viral specific T cells and contributed to T cells exhaustion during chronic hepatitis B virus (HBV) infection. However, modulation of Tim-3 expression was still not fully elucidated. To evaluate the potential viral and inflammatory factors involved in the inductor of Tim-3 expression on T cells, 76 patients with chronic HBV infection (including 40 chronic hepatitis B [CHB] and 36 asymptomatic HBV carriers [AsC]) and 40 of normal controls (NCs) were enrolled in this study. Tim-3 expressions on CD4⁺ and CD8⁺ T cells were assessed in response to HBV-encoding antigens, HBV peptide pools, and common γ-chain (γc) cytokines stimulation by flow cytometry. HBV peptides and anti-CD3/CD28 directly induced Tim-3 expression on T cells. γc cytokines also drive Tim-3 up-regulations on both CD4⁺ and CD8⁺ T cells in patients with chronic HBV infection. However, γc cytokines did not enhance the Tim-3 inductions by either anti-CD3/CD28 or HBV peptides stimulation. Furthermore, γc cytokines-mediated Tim-3 induction could not be abrogated by γc cytokine receptor-neutralizing antibodies. The current results suggested that elevation of Tim-3 expression on T cells could be regulated by both antigen-dependent and -independent manner in patients with chronic HBV infection. The role of γc cytokines in modulation of inhibitory pathway might be evaluated as immunotherapies in humans.

A review of the importance of immune responses in luminal B breast cancer

Historically, the immune environment was not considered an important target for breast cancer treatment. However, the association of lymphocytic infiltrates in triple negative and HER-2 over-amplified breast cancer subtypes with better outcomes, has provoked interest in evaluating the role of the immune system in the luminal B subtype that accounts for 39% of breast cancers and has a poor patient prognosis. It is unknown which immunosuppressive cell types or molecules (e.g., checkpoint molecules) are relevant, or where measurement is most informative. We hypothesize that a profound immunosuppressive tumor and/or lymph node milieu is prognostic and impacts on responses to therapies.

Reversing T-cell Dysfunction and Exhaustion in Cancer

In the context of chronic antigen exposure in chronic viral infections and cancer, T cells become exhausted/dysfunctional. These exhausted T cells exhibit defective proliferative capacities and cytokine production, but are not totally inert and may exert lytic functions. Importantly, exhausted T cells upregulate multiple inhibitory receptors/immune checkpoints that bind to their ligands expressed by tumor cells and antigen-presenting cells in the tumor microenvironment (TME). Immune checkpoint blockades with anti-CTL antigen 4 (CTLA-4) and/or anti-programmed death 1 (PD-1) mAbs successfully reinvigorate tumor-infiltrating T lymphocytes and provide persistent clinical benefits to a large number of patients with advanced cancer. This great and long-awaited success for the immunotherapy of cancer has infused considerable enthusiasm in the field of oncology and fostered the development of combinatorial strategies to target the multiple mechanisms of tumor-induced T-cell dysfunction. Here, we review the critical immunoregulatory mechanisms driving T-cell exhaustion in the TME. We also discuss the development of promising combinatorial immunotherapies to counteract the mechanisms of tumor-induced T-cell dysfunction to improve the clinical efficacy of current immune checkpoint blockades. As our understanding of the mechanisms supporting tumor-induced T-cell dysfunction improves based upon preclinical and clinical studies, we expect that novel combinatorial immunotherapies will emerge to improve the clinical outcome of patients with advanced cancers.

Adaptive resistance to anti-PD1 therapy by Tim-3 upregulation is mediated by the PI3K-Akt pathway in head and neck cancer

Programmed Death 1 (PD-1) and T cell Ig and mucin domain-3 protein (Tim-3) are immune checkpoint receptors that are expressed on tumor-infiltrating lymphocytes (TIL) in tumor-bearing mice and humans. As anti-PD-1 single agent response rates are only <20% in head and neck squamous cell carcinoma (HNSCC) patients, it is important to understand how multiple inhibitory checkpoint receptors maintain suppressed cellular immunity. One such receptor, Tim-3, activates downstream proliferative pathways through Akt/S6, and is highly expressed in dysfunctional TIL. We observed that PD-1 and Tim-3 co-expression was associated with a more exhausted phenotype, with the highest PD-1 levels on TIL co-expressing Tim-3. Dampened Akt/S6 phosphorylation in these PD-1⁺Tim-3⁺ TIL, when the PD-1 pathway was ligated, suggested that signaling cross-talk could lead to escape through Tim-3 expression. Indeed, PD-1 blockade of human HNSCC TIL led to further Tim-3 upregulation, supporting a circuit of compensatory signaling and potentially permitting escape from anti-PD-1 blockade in the tumor microenvironment. Also, in a murine HNC tumor model that is partially responsive to anti-PD-1 therapy, Tim-3 was upregulated in TIL from persistently growing tumors. Significant antitumor activity was observed after sequential addition of anti-Tim-3 mAb to overcome adaptive resistance to anti-PD-1 mAb. This increased Tim-3-mediated escape of exhausted TIL from PD-1 inhibition that was mediated by phospho-inositol-3 kinase (PI3K)/Akt complex downstream of TCR signaling but not cytokine-mediated pathways. Taken together, we conclude that during PD-1 blockade, TIL upregulate Tim-3 in a PI3K/Akt-dependent manner, providing further support for dual targeting of these molecules for more effective cancer immunotherapy.