Interleukin-2 signals converge in a lymphoid-dendritic cell pathway that promotes anticancer immunity

Current landscape and future prospects of interleukin-2 receptor (IL-2R) agonists in cancer immunotherapy

Immune checkpoint blockade (ICB) has significantly improved the survival for many patients with advanced malignancy. However, fewer than 50% of patients benefit from ICB, highlighting the need for more effective immunotherapy options. High-dose interleukin-2 (HD IL-2) immunotherapy, which is approved for patients with metastatic melanoma and renal cell carcinoma, stimulates CD8+ T cells and NK cells and can generate durable responses in a subset of patients. Moreover, HD IL-2 may have potential efficacy in patients whose disease has progressed following ICB and plays a vital role in expanding tumor-infiltrating lymphocyte (TIL) in TIL therapy. Despite its potential, the use of HD IL-2 is limited by severe toxicities such as hypotension and vascular leak syndrome. Additionally, only a few patients achieve a good outcome after HD IL-2 therapy. To address these challenges, numerous next-generation IL-2 receptor (IL-2 R) agonists have been developed to exhibit treatment effects while minimizing adverse events. This review will explore IL-2 biology, the clinical application of HD IL-2 therapy, and the development of novel IL-2 R agonists for cancer immunotherapy.

The role of interleukin (IL)-2 cytokine family in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder, which primarily impacts the nervous system, marked by its immune and inflammatory characteristics. The interleukin-2 (IL-2) cytokine family has a crucial role in regulating both neuroinflammation and immune activity, positioning it as one of the critical immune pathways in PD. Balancing pro-inflammatory and anti-inflammatory signals in PD heavily depends on the IL-2 cytokine family, that includes IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21. This balance is vital for neuron survival and resistance to degeneration. Disruptions in IL-2 signaling can upset the equilibrium among regulatory T cells (Tregs) and pro-inflammatory T cells, such as Th1 and Th17, further aggravating the chronic neuroinflammation typical of PD. In PD, a decline in IL-2 or receptor dysfunction can hinder Treg activity, leading to increased inflammation and neurodegeneration. Similarly, IL-15 and IL-21 supports cytotoxic immune cell function, including natural killer (NK) cells and CD8+ T cells, which may exacerbate neuronal damage by sustaining pro-inflammatory processes. Moreover, IL-4 and IL-7 have anti-inflammatory roles in maintaining T cell homeostasis, and their dysregulation can contribute to interruption of the blood-brain barrier and increased infiltration of immune cells into the central nervous system. Targeting the IL-2 cytokine family in Parkinson's disease has shown therapeutic potential by expanding Tregs, which reduce neuroinflammation and promote dopaminergic neuron survival. Recombinant IL-2 and IL-2/anti-IL-2 complexes have demonstrated efficacy in animal models, enhancing Treg function and leading to improved neuroprotection. Additionally, IL-4-based therapies have been explored for their ability to shift microglia toward a neuroprotective phenotype, further enhancing neuronal survival by modulating inflammatory responses and cellular metabolism. Current research is exploring how to optimize cytokine delivery while minimizing immune side effects, with the goal of developing more targeted therapies for PD.

A glimpse into the application of the immunomodulatory effect of IL-2 in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease, which is mainly caused by the imbalance of immune cells. Current treatment regimens predominately rely on corticosteroids and immunosuppressive agents, accompanied by various side effects. Interleukin-2 (IL-2) is deemed an important cytokine for innate immune cells and adaptive immune cells, especially for the promotion of Treg cells. By combining IL-2/IL-2R system with engineered T cell-based immunotherapies to enhance the therapeutic efficacy of engineered T cells shows its potential in autoimmune diseases. But the pleiotropy of IL-2 may cause simultaneous stimulation and systemic toxicity, limiting its therapeutic use. There is a growing focus on using IL-2 in combination strategies for synergistic immune enhancement. In this article, we review the IL-2/IL-2R signaling, including IL-2 dependent signaling and IL-2 independent signaling, and discuss its functions in regulation of different immune cells. In addition, we summarize major clinical application of low-dose IL-2 treatment in SLE with or without other agents, such as rapamycin, tocilizumab and rituximab, present the IL-2 variants and fusion proteins designed for SLE, and highlight the future trends for research on these cytokine-based immunotherapies. It will help to design further optimized IL-2-based therapy for SLE.

Based on the immune system: the role of the IL-2 family in pancreatic disease

The IL-2 family, consisting of IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21, is a key regulator of the immune response. As an important endocrine and digestive organ, the function of the pancreas is regulated by the immune system. Studies have shown that each cytokine of the IL-2 family influences the occurrence and development of pancreatic diseases by participating in the regulation of the immune system. In this paper, we review the structural and functional characteristics of IL-2 family members, focus on their molecular mechanisms in pancreatic diseases including acute pancreatitis, chronic pancreatitis and pancreatic cancer, and highlight the importance of the related proteins in the regulation of immune response and disease progression, which will provide valuable insights for new biomarkers in pancreatic diseases, early diagnosis of the diseases, assessment of the disease severity, and development of new therapeutic regimens. The insights of the study are summarized in the following sections.

Antibody-based delivery of interleukin-2 modulates the immunosuppressive tumor microenvironment and achieves cure in pancreatic ductal adenocarcinoma syngeneic mice

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and deadly type of cancer, with an extremely low five-year overall survival rate. To date, current treatment options primarily involve various chemotherapies, which often prove ineffective and are associated with substantial toxicity. Furthermore, immunotherapies utilizing checkpoint inhibitors have shown limited efficacy in this context, highlighting an urgent need for novel therapeutic strategies. This study investigates the preclinical efficacy of an innovative targeted therapy based on antibody-cytokine fusion proteins, specifically interleukin-2 (IL-2), a pivotal driver of cell-mediated immunity, fused to L19 antibody, which selectively binds to extra domain B of fibronectin (EDB-FN1) expressed in the tumor microenvironment.

METHODS

We tested the effectiveness of different immunocytokines through in vivo characterization in syngeneic C57BL/6J orthotopic mouse models of PDAC. Based on these results, we decided to focus on L19-IL2. To assess the efficacy of this immunocytokine we developed an ex-vivo immune-spheroid interaction platform derived from murine 3D pancreatic cultures, and telomerase reverse transcriptase (TERT) specific T-lymphocytes. Moreover, we evaluated the anti-cancer effect of L19-IL2 in combination with standard therapy in vivo experiments in PDAC mouse models. Tumor samples collected after the treatments were characterized for tumor infiltrating immune cell components by bulk RNA sequencing (RNA-seq) and spatial transcriptomics (Stereo-seq) analysis.

RESULTS

The tumor-targeted L19-IL2 fusion protein demonstrated potent, dose-dependent anti-tumor activity in mice with pancreatic tumors resistant to standard chemotherapy. Spatial Transcriptomics (ST) and RNA-seq analyses indicated that L19-IL2 treatment induced a significant influx of immune cells into the tumor microenvironment, with these cells expressing activation markers like granzymes, perforins, and the IL-2 receptors.

CONCLUSIONS

Our results demonstrated that L19-IL2 enhances immune infiltration and cytotoxicity, remodeling the "cold" tumor microenvironment (TME) in PDAC. This innovative antibody-cytokine fusion protein improves therapeutic outcomes, paving the way for novel targeted treatment strategies in PDAC.

An IL-2 mutein increases regulatory T cell suppression of dendritic cells via IL-10 and CTLA-4 to promote T cell anergy

Interleukin-2 (IL-2) variants with increased CD25 dependence that selectively expand Foxp3+ regulatory T (TR) cells are in clinical trials for treating inflammatory diseases. Using an Fc-fused IL-2 mutein (Fc.IL-2 mutein) we developed that prevents diabetes in non-obese diabetic (NOD) mice, we show that Fc.IL-2 mutein induced an activated TR population with elevated proliferation, a transcriptional program associated with Stat5- and T cell receptor-dependent gene modules, and high IL-10 and CTLA-4 expression. Increased IL-10 signaling limited surface major histocompatibility complex class II upregulation during conventional dendritic cell (cDC) maturation, while increased CTLA-4-dependent transendocytosis led to the transfer of CD80 and CD86 co-stimulatory ligands from maturing cDCs to TR cells. In NOD mice, Fc.IL-2 mutein treatment promoted the suppression of cDCs in the inflamed pancreas and pancreatic lymph nodes, resulting in T cell anergy. Thus, IL-2 mutein-expanded TR cells have enhanced functional properties and restrict cDC function, offering promise for targeted immunotherapy use in autoimmune disease.

IL-2/anti-IL-2 antibody complexes augment immune responses to therapeutic cancer vaccines

One driver of the high failure rates of clinical trials for therapeutic cancer vaccines is likely the inability to sufficiently engage conventional dendritic cells (cDCs), the antigen-presenting cell (APC) subset that is specialized in priming antitumor T cells. Here, we demonstrate that, relative to vaccination with an injectable mesoporous silica rod (MPS) vaccine alone (Vax), combining MPS vaccines with CD122-biased IL-2/anti-IL-2 antibody complexes (IL-2cx) drives ~3-fold expansion of cDCs at the vaccination sites, vaccine-draining lymph nodes, and spleens of treated mice. Furthermore, relative to Vax alone, Vax+IL-2cx led to a ~3-fold increase in the numbers of CD8+ T cells and ~15-fold increase in the numbers of NK cells at the vaccination site. Notably, with both the model protein antigen OVA as well as various peptide neoantigens, Vax+IL-2cx induced ~5 to 30-fold greater numbers of circulating antigen-specific CD8+ T cells relative to Vax alone. We further demonstrate that Vax+IL-2cx leads to significantly improved efficacy in the MC38 colon carcinoma model relative to either monotherapy alone, driving complete regressions in 50% of mice in a cDC-dependent manner. Relative to vaccine alone, Vax+IL-2cx led to comparable numbers of CD8+ T cells, but markedly greater numbers of NK cells and activated cDCs in the B16F10 melanoma tumor microenvironment post-therapy. Taken together, these findings suggest that the administration of factors that engage both the cDC-CD8+ T cell and cDC-NK cell axes can boost the potency of therapeutic cancer vaccines.

Interleukin-2 immunotherapy reveals human regulatory T cell subsets with distinct functional and tissue-homing characteristics

Due to its stimulatory potential for immunomodulatory CD4+ regulatory T (Treg) cells, low-dose interleukin-2 (IL-2) immunotherapy has gained considerable attention for the treatment of autoimmune diseases. In this investigator-initiated single-arm non-placebo-controlled phase-2 clinical trial of low-dose IL-2 immunotherapy in systemic lupus erythematosus (SLE) patients, we generated a comprehensive atlas of in vivo human immune responses to low-dose IL-2. We performed an in-depth study of circulating and cutaneous immune cells by imaging mass cytometry, high-parameter flow cytometry, transcriptomics, and targeted serum proteomics. Low-dose IL-2 stimulated various circulating immune cells, including Treg cells with a skin-homing phenotype that appeared in the skin of SLE patients in close interaction with endothelial cells. Analysis of surface proteins and transcriptomes revealed different IL-2-driven Treg cell activation programs, including gut-homing CD38+, skin-homing HLA-DR+, and highly proliferative inflammation-homing CD38+ HLA-DR+ Treg cells. Collectively, these data define the distinct human Treg cell subsets that are responsive to IL-2 immunotherapy.

Harnessing IL-2 for immunotherapy against cancer and chronic infection: a historical perspective and emerging trends

IL-2 therapy, which enhances the function of CD8 + T cells, was initially employed as the cornerstone of immunotherapy against cancer. However, the impact of this therapy extends beyond CD8 + T cells to cells expressing IL-2R, such as endothelial cells and regulatory T cells (Tregs), resulting in various side effects. Consequently, IL-2 therapy has taken a step back from the forefront of treatment. Immune checkpoint inhibitors (ICIs), such as anti-PD-1/PD-L1 antibodies and CTLA-4 antibodies, are used because of their durable therapeutic responses and the reduced incidence of side effects. Nevertheless, only a small fraction of cancer patients respond to ICIs, and research on IL-2 as a combination treatment to improve the efficacy of these ICIs is ongoing. To mitigate side effects, efforts have focused on developing IL-2 variants that do not strongly bind to cells expressing IL-2Rα and favor signaling through IL-2Rβγ. However, recent studies have suggested that, in the context of persistent antigen stimulation models, effective stimulation of antigen-specific exhausted CD8 + T cells in combination with PD-1 inhibitors requires either 1) binding to IL-2Rα or 2) delivery via a fusion with PD-1. This review explores the historical context of IL-2 as an immunotherapeutic agent and discusses future directions for its use in cancer immunotherapy.

Crucial role of dendritic cells in the generation of anti-tumor T-cell responses and immunogenic tumor microenvironment to suppress tumor development

Dendritic cells (DCs) are known as unique professional antigen (Ag)-presenting cells (APCs) to prime naïve T cells for the initiation of adaptive immunity. While DCs are believed to play a pivotal role in generating anti-tumor T-cell responses, the importance of DCs in the protection from the progression of tumors remains elusive. Here, we show how the constitutive deficiency of CD11chi DCs influences the progression of tumors with the use of binary transgenic mice with constitutive loss of CD11chi DCs. Constitutive loss of CD11chi DCs not only enhances the progression of tumors but also reduces the responses of Ag-specific T cells. Furthermore, the congenital deficiency of CD11chi DCs generates the immunosuppressive tumor microenvironment (TME) that correlates with the marked accumulation of myeloid-derived suppressor cells (MDSCs) and the prominent productions of immunosuppressive mediators. Thus, our findings suggest that CD11chi DCs are crucial for generating anti-tumor T-cell responses and immunogenic TME to suppress the development of tumors.

CD8-Targeted IL2 Unleashes Tumor-Specific Immunity in Human Cancer Tissue by Reviving the Dysfunctional T-cell Pool

Tumor-specific CD8+ T cells are key effectors of antitumor immunity but are often rendered dysfunctional in the tumor microenvironment. Immune-checkpoint blockade can restore antitumor T-cell function in some patients; however, most do not respond to this therapy, often despite T-cell infiltration in their tumors. We here explored a CD8-targeted IL2 fusion molecule (CD8-IL2) to selectively reactivate intratumoral CD8+ T cells in patient-derived tumor fragments. Treatment with CD8-IL2 broadly armed intratumoral CD8+ T cells with enhanced effector capacity, thereby specifically enabling reinvigoration of the dysfunctional T-cell pool to elicit potent immune activity. Notably, the revival of dysfunctional T cells to mediate effector activity by CD8-IL2 depended on simultaneous antigen recognition and was quantitatively and qualitatively superior to that achieved by PD-1 blockade. Finally, CD8-IL2 was able to functionally reinvigorate T cells in tumors resistant to anti-PD-1, underscoring its potential as a novel treatment strategy for patients with cancer. Significance: Reinvigorating T cells is crucial for response to checkpoint blockade therapy. However, emerging evidence suggests that the PD-1/PD-L1 axis is not the sole impediment for activating T cells within tumors. Selectively targeting cytokines toward specific T-cell subsets might overcome these barriers and stimulate T cells within resistant tumors. See related article by Moynihan et al., p. 1206 (32).

Delayed tumor-draining lymph node irradiation preserves the efficacy of combined radiotherapy and immune checkpoint blockade in models of metastatic disease

Cancer resistance to immune checkpoint inhibitors motivated investigations into leveraging the immunostimulatory properties of radiotherapy to overcome immune evasion and to improve treatment response. However, clinical benefits of radiotherapy-immunotherapy combinations have been modest. Routine concomitant tumor-draining lymph node irradiation (DLN IR) might be the culprit. As crucial sites for generating anti-tumor immunity, DLNs are indispensable for the in situ vaccination effect of radiotherapy. Simultaneously, DLN sparing is often not feasible due to metastatic spread. Using murine models of metastatic disease in female mice, here we demonstrate that delayed (adjuvant), but not neoadjuvant, DLN IR overcomes the detrimental effect of concomitant DLN IR on the efficacy of radio-immunotherapy. Moreover, we identify IR-induced disruption of the CCR7-CCL19/CCL21 homing axis as a key mechanism for the detrimental effect of DLN IR. Our study proposes delayed DLN IR as a strategy to maximize the efficacy of radio-immunotherapy across different tumor types and disease stages.

PD-1: A critical player and target for immune normalization

Immune system imbalances contribute to the pathogenesis of several different diseases, and immunotherapy shows great therapeutic efficacy against tumours and infectious diseases with immune-mediated derivations. In recent years, molecules targeting the programmed cell death protein 1 (PD-1) immune checkpoint have attracted much attention, and related signalling pathways have been studied clearly. At present, several inhibitors and antibodies targeting PD-1 have been utilized as anti-tumour therapies. However, increasing evidence indicates that PD-1 blockade also has different degrees of adverse side effects, and these new explorations into the therapeutic safety of PD-1 inhibitors contribute to the emerging concept that immune normalization, rather than immune enhancement, is the ultimate goal of disease treatment. In this review, we summarize recent advancements in PD-1 research with regard to immune normalization and targeted therapy.

Colorectal cancer subtyping and prognostic model construction based on interleukin-related genes

Members of the interleukin (IL) family are closely linked to cancer development and progression. However, research on the prognosis of colorectal cancer (CRC) related to IL is still lacking. This study investigated new CRC prognostic markers and offered new insights for CRC prognosis and treatment. CRC-related data and IL gene data were collected from public databases. Sample clustering was done with the NMF package to divide samples into different subtypes. Differential, enrichment, survival, and immune analyses were conducted on subtypes. A prognostic model was constructed using regression analysis. Drug sensitivity analysis was performed using GDSC database. Western blot analysis was performed to assess the effect of IL-7 on the JAK/STAT signaling pathway. Flow cytometry was used to examine the impact of IL-7 on CD8+ T cell apoptosis. Two CRC subtypes based on IL-associated genes were obtained. Cluster 1 had a higher survival rate than cluster 2, and they showed differences in some immune levels. The two clusters were mainly enriched in the JAK-STAT signaling pathway, T helper 17 cell differentiation, and the IL-17 signaling pathway. An 11-gene signature was built, and risk score was an independent prognosticator for CRC. The low-risk group showed a higher sensitivity to nine common targeted anticancer drugs. Western blot and flow cytometry results demonstrated that IL-7 could phosphorylate STAT5 and promote survival of CD8+ T cells. In conclusion, this study divided CRC samples into two IL-associated subtypes and obtained an 11-gene signature. In addition, targeted drugs that may improve the prognosis of patients with CRC were identified. These findings are of paramount importance for patient prognosis and CRC treatment.NEW & NOTEWORTHY We identified two clusters with significant survival differences in colorectal cancer (CRC) based on interleukin-related genes, constructed an 11-gene risk score model that can independently predict the prognosis of CRC, and explored some targeted drugs that may improve the prognosis of patients with CRC. The results of this study have important implications for the prognosis and treatment of CRC.

IL-2 promotes expansion and intratumoral accumulation of tumor infiltrating dendritic cells in pancreatic cancer

This study aims to investigate the diagnostic potential of IL-2 for PDAC and develop a method to improve the dendritic cell (DC) based vaccine against PDAC. The gene expression data and clinical characteristics information for 178 patients with PDAC were obtained from The Cancer Genome Atlas (TCGA). DCs were isolated from Human peripheral blood mononuclear cells (PBMCs) and were cultured in 4 different conditions. DCs were pulsed by tumor cell lysates or KRAS G12D1 - 23 peptide, and then used to activate T cells. The mixture of DCs and T cells were administered to xenograft mouse model through the tail vein. The infiltration of DCs and T cells were detected by immunohistochemistry. The generation of KRAS G12D mutation specific cytotoxic T cells was determined by in vitro killing assay. We observed that PDAC patients with higher IL-2 mRNA levels exhibited improved overall survival and increased infiltration of CD8 + T cells, NK cells, naïve B cells, and resting myeloid DCs in the tumor microenvironment. IL-2 alone did not enhance DC proliferation, antigen uptake, or apoptosis inhibition unless co-cultured with PBMCs. DCs co-cultured with PBMCs in IL-2-containing medium demonstrated the strongest tumor repression effect in vitro and in vivo. Compared to DCs obtained through the traditional method (cultured in medium containing GM-CSF and IL-4), DCs cultured with PBMCs, and IL-2 exhibited increased tumor infiltration capacity, potentially facilitating sustained T cell immunity. DCs cultured in the PBMCs-IL-2 condition could promote the generation of cytotoxic T cells targeting tumor cells carrying KRAS G12D mutation.

Fine tuning of the innate and adaptive immune responses by Interleukin-2

Novel immunotherapies for cancer and other diseases aim to trigger the immune system to produce durable responses, while overcoming the immunosuppression that may contribute to disease severity, and in parallel considering immunosafety aspects. Interleukin-2 (IL-2) was one of the first cytokines that the FDA approved as a cancer-targeting immunotherapy. However, in the past years, IL-2 immunotherapy is not actively offered to patients, due to limited efficacy, when compared to other novel immunotherapies, and the associated severe adverse events. In order to design improved in vitro and in vivo models, able to predict the efficacy and safety of novel IL-2 alternatives, it is important to delineate the mechanistic immunological events triggered by IL-2. Particularly, in this review we will discuss the effects IL-2 has with the bridging cell type of the innate and adaptive immune responses, dendritic cells. The pathways involved in the regulation of IL-2 by dendritic cells and T-cells in cancer and autoimmune disease will also be explored.

Is There a Current Role for Combination Chemotherapy or High-Dose Interleukin 2 in Melanoma?

ABSTRACT

Immune checkpoint inhibition and targeted therapies have revolutionized the treatment of melanoma. However, chemotherapy and interleukin 2 (IL-2) therapy may still have a role in the later-line treatment of patients who do not have durable responses to other treatments. Chemotherapy can work transiently in patients whose disease has progressed on immune checkpoint inhibitors and for whom there are no appropriate targeted therapy options. High-dose IL-2 therapy can still be effective for a very small number of patients following progression on other therapies. In addition, modified IL-2 agents and IL-2 in combination with tumor-infiltrating lymphocyte therapy may play a role in future treatments for melanoma.

Heating tumors with tumor cell-derived nanoparticles to enhance chemoimmunotherapy for colorectal cancer

Aim: To investigate the mechanism of doxorubicin (DOX)-induced immunogenic cell death (ICD) and to improve immunotherapy efficacy. Materials & methods: In this study, hybrid vesicles containing DOX (HV-DOX) were prepared by thin-film hydration with extrusion, and the formulated nanoparticles were characterized physically. Furthermore, in vitro experiments and animal models were used to investigate the efficacy and new mechanisms of chemotherapy combined with immunotherapy. Results: DOX improved tumor immunogenicity by alkalinizing lysosomes, inhibiting tumor cell autophagy and inducing ICD. HVs could activate dendritic cell maturation, synergistically enhancing chemotherapeutic immunity. Conclusion: The mechanism of DOX-induced ICD was explored, and antitumor immunity was synergistically activated by HV-DOX to improve chemotherapeutic drug loading and provide relevant antigenic information.

A Review of Current and Pipeline Drugs for Treatment of Melanoma

Malignant melanoma is the most aggressive form of skin cancer. Standard treatment options include surgery, radiation therapy, systemic chemotherapy, targeted therapy, and immunotherapy. Combining these modalities often yields better responses. Surgery is suitable for localized cases, sometimes involving lymph node dissection and biopsy, to assess the spread of the disease. Radiation therapy may be sometimes used as a standalone treatment or following surgical excision. Systemic chemotherapy, while having low response rates, is utilized as part of combination treatments or when other methods fail. The development of resistance to systemic chemotherapies and associated side effects have prompted further research and clinical trials for novel approaches. In the case of advanced-stage melanoma, a comprehensive approach may be necessary, incorporating targeted therapies and immunotherapies that demonstrate significant antitumor activity. Targeted therapies, including inhibitors targeting BRAF, MEK, c-KIT, and NRAS, are designed to block the specific molecules responsible for tumor growth. These therapies show promise, particularly in patients with corresponding mutations. Combination therapy, including BRAF and MEK inhibitors, has been evidenced to improve progression-free survival; however, concerns about resistance and cutaneous toxicities highlight the need for close monitoring. Immunotherapies, leveraging tumor-infiltrating lymphocytes and CAR T cells, enhance immune responses. Lifileucel, an FDA-approved tumor-infiltrating lymphocyte therapy, has demonstrated improved response rates in advanced-stage melanoma. Ongoing trials continue to explore the efficacy of CAR T-cell therapy for advanced melanoma. Checkpoint inhibitors targeting CTLA-4 and PD-1 have enhanced outcomes. Emerging IL-2 therapies boost dendritic cells, enhancing anticancer immunity. Oncolytic virus therapy, approved for advanced melanoma, augments treatment efficacy in combination approaches. While immunotherapy has significantly advanced melanoma treatment, its success varies, prompting research into new drugs and factors influencing outcomes. This review provides insights into current melanoma treatments and recent therapeutic advances.

Optimising IL-2 for Cancer Immunotherapy

The key role of T cells in cancer immunotherapy is well established and is highlighted by the remarkable capacity of Ab-mediated checkpoint blockade to overcome T-cell exhaustion and amplify anti-tumor responses. However, total or partial tumor remission following checkpoint blockade is still limited to only a few types of tumors. Hence, concerted attempts are being made to devise new methods for improving tumor immunity. Currently, much attention is being focused on therapy with IL-2. This cytokine is a powerful growth factor for T cells and optimises their effector functions. When used at therapeutic doses for cancer treatment, however, IL-2 is highly toxic. Nevertheless, recent work has shown that modifying the structure or presentation of IL-2 can reduce toxicity and lead to effective anti-tumor responses in synergy with checkpoint blockade. Here, we review the complex interaction of IL-2 with T cells: first during normal homeostasis, then during responses to pathogens, and finally in anti-tumor responses.

CD8 cis-targeted IL-2 drives potent antiviral activity against hepatitis B virus

CD8+ T cells are key antiviral effectors against hepatitis B virus (HBV), yet their number and function can be compromised in chronic infections. Preclinical HBV models displaying CD8+ T cell dysfunction showed that interleukin-2 (IL-2)-based treatment, unlike programmed cell death ligand 1 (PD-L1) checkpoint blockade, could reverse this defect, suggesting its therapeutic potential against HBV. However, IL-2's effectiveness is hindered by its pleiotropic nature, because its receptor is found on various immune cells, including regulatory T (Treg) cells and natural killer (NK) cells, which can counteract antiviral responses or contribute to toxicity, respectively. To address this, we developed a cis-targeted CD8-IL2 fusion protein, aiming to selectively stimulate dysfunctional CD8+ T cells in chronic HBV. In a mouse model, CD8-IL2 boosted the number of HBV-reactive CD8+ T cells in the liver without substantially altering Treg or NK cell counts. These expanded CD8+ T cells exhibited increased interferon-γ and granzyme B production, demonstrating enhanced functionality. CD8-IL2 treatment resulted in substantial antiviral effects, evidenced by marked reductions in viremia and antigenemia and HBV core antigen-positive hepatocytes. In contrast, an untargeted CTRL-IL2 led to predominant NK cell expansion, minimal CD8+ T cell expansion, negligible changes in effector molecules, and minimal antiviral activity. Human CD8-IL2 trials in cynomolgus monkeys mirrored these results, achieving a roughly 20-fold increase in peripheral blood CD8+ T cells without affecting NK or Treg cell numbers. These data support the development of CD8-IL2 as a therapy for chronic HBV infection.

FLT3L-dependent dendritic cells control tumor immunity by modulating Treg and NK cell homeostasis

FLT3-L-dependent classical dendritic cells (cDCs) recruit anti-tumor and tumor-protecting lymphocytes. We evaluate cancer growth in mice with low, normal, or high levels of cDCs. Paradoxically, both low or high numbers of cDCs improve survival in mice with melanoma. In low cDC context, tumors are restrained by the adaptive immune system through influx of effector T cells and depletion of Tregs and NK cells. High cDC numbers favor the innate anti-tumor response, with massive recruitment of activated NK cells, despite high Treg infiltration. Anti CTLA-4 but not anti PD-1 therapy synergizes with FLT3-L therapy in the cDCHi but not in the cDCLo context. A combination of cDC boost and Treg depletion dramatically improves survival of tumor-bearing mice. Transcriptomic data confirm the paradoxical effect of cDC levels on survival in several human tumor types. cDCHi-TregLo state in such patients predicts best survival. Modulating cDC numbers via FLT3 signaling may have therapeutic potential in human cancer.

An IL-2 mutein increases IL-10 and CTLA-4-dependent suppression of dendritic cells by regulatory T cells

Interleukin-2 (IL-2) variants with increased CD25 dependence that selectively expand Foxp3+ regulatory T (TR) cells are in clinical trials for treating inflammatory diseases. Using an Fc-fused IL-2 mutein (Fc.IL-2 mutein) we developed that prevents diabetes in non-obese diabetic (NOD) mice, we show that Fc.IL-2 mutein induced an activated TR population with elevated proliferation, a transcriptional program associated with Stat5- and TCR-dependent gene modules, and high IL-10 and CTLA-4 expression. Increased IL-10 signaling limited surface MHC class II upregulation during conventional dendritic cell (cDC) maturation, while increased CTLA-4-dependent transendocytosis led to the transfer of CD80 and CD86 costimulatory ligands from maturing cDCs to TR cells. In NOD mice, Fc.IL-2 mutein treatment promoted the suppression of cDCs in the inflamed pancreas and pancreatic lymph nodes resulting in T cell anergy. Thus, IL-2 mutein-expanded TR cells have enhanced functional properties and restrict cDC function, offering promise for targeted immunotherapy use in autoimmune disease.

PD-1 signaling negatively regulates the common cytokine receptor γ chain via MARCH5-mediated ubiquitination and degradation to suppress anti-tumor immunity

Combination therapy with PD-1 blockade and IL-2 substantially improves anti-tumor efficacy comparing to monotherapy. The underlying mechanisms responsible for the synergistic effects of the combination therapy remain enigmatic. Here we show that PD-1 ligation results in BATF-dependent transcriptional induction of the membrane-associated E3 ubiquitin ligase MARCH5, which mediates K27-linked polyubiquitination and lysosomal degradation of the common cytokine receptor γ chain (γc). PD-1 ligation also activates SHP2, which dephosphorylates γcY357, leading to impairment of γc family cytokine-triggered signaling. Conversely, PD-1 blockade restores γc level and activity, thereby sensitizing CD8+ T cells to IL-2. We also identified Pitavastatin Calcium as an inhibitor of MARCH5, which combined with PD-1 blockade and IL-2 significantly improves the efficacy of anti-tumor immunotherapy in mice. Our findings uncover the mechanisms by which PD-1 signaling antagonizes γc family cytokine-triggered immune activation and demonstrate that the underlying mechanisms can be exploited for increased efficacy of combination immunotherapy of cancer.

Immune microenvironment of cervical cancer and the role of IL-2 in tumor promotion

The tumor microenvironment (TME) is a heterogeneous mixture of resident and tumor cells that maintain close communication through their secretion products. The composition of the TME is dynamic and complex among the different types of cancer, where the immune cells play a relevant role in the elimination of tumor cells, however, under certain circumstances they contribute to tumor development. In cervical cancer (CC) the human papilloma virus (HPV) shapes the microenvironment in order to mediate persistent infections that favors transformation and tumor development. Interleukin-2 (IL-2) is an important TME cytokine that induces CD8+ effector T cells and NKs to eliminate tumor cells, however, IL-2 can also suppress the immune response through Treg cells. Recent studies have shown that CC cells express the IL-2 receptor (IL-2R), that are induced to proliferate at low concentrations of exogenous IL-2 through alterations in the JAK/STAT pathway. This review provides an overview of the main immune cells that make up the TME in CC, as well as the participation of IL-2 in the tumor promotion. Finally, it is proposed that the low density of IL-2 produced by immunocompetent cells is used by tumor cells through its IL-2R as a mechanism to proliferate simultaneously depleting this molecule in order to evade immune response.

Modified Rice Bran Arabinoxylan by Lentinus edodes Mycelial Enzyme as an Immunoceutical for Health and Aging-A Comprehensive Literature Review

Rice bran arabinoxylan compound (RBAC) is derived from defatted rice bran enzymatically treated with Lentinus edodes mycelium. This review explores biologically active compounds and mechanisms of action that support RBAC as an immunomodulating nutraceutical in generally healthy and/or aging individuals. Thirty-seven (n = 37) primary research articles fulfilled the selection criteria for review. Most research is based on Biobran MGN-3, which consists of complex heteropolysaccharides with arabinoxylan as its primary structure while also containing galactan and glucan. RBAC was found to invoke immunological activities through direct absorption via the digestive tract and interaction with immune cells at the Peyer's patches. RBAC was shown to promote innate defence by upregulating macrophage phagocytosis and enhancing natural killer cell activity while lowering oxidative stress. Through induction of dendritic cell maturation, RBAC also augments adaptive immunity by promoting T and B lymphocyte proliferation. RBAC acts as an immunomodulator by inhibiting mast cell degranulation during allergic reactions, attenuating inflammation, and downregulating angiogenesis by modulating cytokines and growth factors. RBAC has been shown to be a safe and effective nutraceutical for improving immune health, notably in aging individuals with reduced immune function. Human clinical trials with geriatric participants have demonstrated RBAC to have prophylactic benefits against viral infection and may improve their quality of life. Further research should explore RBAC's bioavailability, pharmacodynamics, and pharmacokinetics of the complex heteropolysaccharides within. Translational research to assess RBAC as a nutraceutical for the aging population is still required, particularly in human studies with larger sample sizes and cohort studies with long follow-up periods.

Engineered anti-PDL1 with IFNα targets both immunoinhibitory and activating signals in the liver to break HBV immune tolerance

OBJECTIVE

The purpose of this study is to develop an anti-PDL1-based interferon (IFN) fusion protein to overcome the chronic hepatitis B virus (HBV)-induced immune tolerance, and combine this immunotherapy with a HBV vaccine to achieve the functional cure of chronic hepatitis B (CHB) infection.

DESIGN

We designed an anti-PDL1-IFNα heterodimeric fusion protein, in which one arm was derived from anti-PDL1 antibody and the other arm was IFNα, to allow targeted delivery of IFNα into the liver by anti-PDL1 antibody. The effect of the anti-PDL1-IFNα heterodimer on overcoming hepatitis B surface antigen (HBsAg) vaccine resistance was evaluated in chronic HBV carrier mice.

RESULTS

The anti-PDL1-IFNα heterodimer preferentially targeted the liver and resulted in viral suppression, the PD1/PDL1 immune checkpoint blockade and dendritic cell activation/antigen presentation to activate HBsAg-specific T cells, thus breaking immune tolerance in chronic HBV carrier mice. When an HBsAg vaccine was administered soon after anti-PDL1-IFNα heterodimer treatment, we observed strong anti-HBsAg antibody and HBsAg-specific T cell responses for efficient HBsAg clearance in chronic HBV carrier mice that received the combination treatment but not in those that received either single treatment.

CONCLUSIONS

Targeting the liver with an engineered anti-PDL1-IFNα heterodimer can break HBV-induced immune tolerance to an HBsAg vaccine, offering a promising translatable therapeutic strategy for the functional cure of CHB.

Robust IL-2-dependent antitumor immunotherapy requires targeting the high-affinity IL-2R on tumor-specific CD8+ T cells

BACKGROUND

Development of interleukin (IL)-2-dependent antitumor responses focus on targeting the intermediate affinity IL-2R to stimulate memory-phenotypic CD8+ T and natural killer (NK) cells while minimizing regulatory T cell (Treg) expansion. However, this approach may not effectively engage tumor-specific T effector cells. Since tumor-antigen specific T cells upregulate the high-affinity IL-2R, we tested an IL-2 biologic, mouse IL-2/CD25, with selectivity toward the high-affinity IL-2R to support antitumor responses to tumors that vary in their immunogenicity.

METHODS

Mice were first implanted with either CT26, MC38, B16.F10, or 4T1 and after a tumor mass developed, they were treated with high-dose (HD) mouse (m)IL-2/CD25 alone or in combination with anti-programmed cell death protein-1 (PD-1) checkpoint blockade. Tumor growth was monitored and in parallel the immune signature in the tumor microenvironment (TME) was determined by a combination of multiparameter flow cytometry, functional assays, and enumeration of tumor-reactive T cells.

RESULTS

We show that HD mIL-2/CD25, which preferentially stimulates the high-affinity IL-2R, but not IL-2/anti-IL-2 complexes with preferential activity toward the intermediate-affinity IL-2R, supports vigorous antitumor responses to immunogenic tumors as a monotherapy that were enhanced when combined with anti-PD-1. Treatment of CT26-bearing mice with HD mIL-2/CD25 led to a high CD8+:Treg ratio in the TME, increased frequency and function of tumor-specific CD8+ T effector cells with a less exhausted phenotype, and antitumor memory responses.

CONCLUSIONS

Targeting the high-affinity IL-2R on tumor-specific T cells with HD mIL-2/CD25 alone or with PD-1 blockade supports antitumor responses, where the resulting memory response may afford long-term protection against tumor re-emergence.

A systematic review of interleukin-2-based immunotherapies in clinical trials for cancer and autoimmune diseases

BACKGROUND

The cytokine interleukin-2 (IL-2) can stimulate both effector immune cells and regulatory T (Treg) cells. The ability of selectively engaging either of these effects has spurred interest in using IL-2 for immunotherapy of cancer and autoimmune diseases. Thus, numerous IL-2-based biologic agents with improved bias or delivery towards effector immune cells or Treg cells have been developed. This study systematically reviews clinical results of improved IL-2-based compounds.

METHODS

We searched the ClinicalTrials.gov database for registered trials using improved IL-2-based agents and different databases for available results of these studies.

FINDINGS

From 576 registered clinical trials we extracted 36 studies on different improved IL-2-based compounds. Adding another nine agents reported in recent literature reviews and based on our knowledge totalled in 45 compounds. A secondary search for registered clinical trials of each of these 45 compounds resulted in 141 clinical trials included in this review, with 41 trials reporting results.

INTERPRETATION

So far, none of the improved IL-2-based compounds has gained regulatory approval for the treatment of cancer or autoimmune diseases. NKTR-214 is the only compound completing phase 3 studies. The PIVOT IO-001 trial testing the combination of NKTR-214 plus Pembrolizumab compared to Pembrolizumab monotherapy in metastatic melanoma missed its primary endpoints. Also the PIVOT-09 study, combining NKTR-214 with Nivolumab compared to Sunitinib or Cabozantinib in advanced renal cell carcinoma, missed its primary endpoint. Trials in autoimmune diseases are currently in early stages, thus not allowing definite conclusions on efficacy.

FUNDING

This work was supported by public funding agencies.

Integrative analysis of a novel super-enhancer-associated lncRNA prognostic signature and identifying LINC00945 in aggravating glioma progression

BACKGROUND

Super-enhancers (SEs), driving high-level expression of genes with tumor-promoting functions, have been investigated recently. However, the roles of super-enhancer-associated lncRNAs (SE-lncRNAs) in tumors remain undetermined, especially in gliomas. We here established a SE-lncRNAs expression-based prognostic signature to choose the effective treatment of glioma and identify a novel therapeutic target.

METHODS

Combined analysis of RNA sequencing (RNA-seq) data and ChIP sequencing (ChIP-seq) data of glioma patient-derived glioma stem cells (GSCs) screened SE-lncRNAs. Chinese Glioma Genome Atlas (CGGA) and The Cancer Genome Atlas (TCGA) datasets served to construct and validate SE-lncRNA prognostic signature. The immune profiles and potential immuno- and chemotherapies response prediction value of the signature were also explored. Moreover, we verified the epigenetic activation mechanism of LINC00945 via the ChIP assay, and its effect on glioma was determined by performing the functional assay and a mouse xenograft model.

RESULTS

6 SE-lncRNAs were obtained and identified three subgroups of glioma patients with different prognostic and clinical features. A risk signature was further constructed and demonstrated to be an independent prognostic factor. The high-risk group exhibited an immunosuppressive microenvironment and was higher enrichment of M2 macrophage, regulatory T cells (Tregs), and Cancer-associated fibroblasts (CAFs). Patients in the high-risk group were better candidates for immunotherapy and chemotherapeutics. The SE of LINC00945 was further verified via ChIP assay. Mechanistically, BRD4 may mediate epigenetic activation of LINC00945. Additionally, overexpression of LINC00945 promoted glioma cell proliferation, EMT, migration, and invasion in vitro and xenograft tumor formation in vivo.

CONCLUSION

Our study constructed the first prognostic SE-lncRNA signature with the ability to optimize the choice of patients receiving immuno- and chemotherapies and provided a potential therapeutic target for glioma.

Biased IL-2 signals induce Foxp3-rich pulmonary lymphoid structures and facilitate long-term lung allograft acceptance in mice

Transplantation of solid organs can be life-saving in patients with end-stage organ failure, however, graft rejection remains a major challenge. In this study, by pre-conditioning with interleukin-2 (IL-2)/anti-IL-2 antibody complex treatment biased toward IL-2 receptor α, we achieved acceptance of fully mismatched orthotopic lung allografts that remained morphologically and functionally intact for more than 90 days in immunocompetent mice. These allografts are tolerated by the actions of forkhead box p3 (Foxp3)⁺ regulatory T (Treg) cells that home to the lung allografts. Although counts of circulating Treg cells rapidly return to baseline following cessation of IL-2 treatment, Foxp3⁺ Treg cells persist in peribronchial and peribronchiolar areas of the grafted lungs, forming organized clusters reminiscent of inducible tertiary lymphoid structures (iTLS). These iTLS in lung allografts are made of Foxp3⁺ Treg cells, conventional T cells, and B cells, as evidenced by using microscopy-based distribution and neighborhood analyses. Foxp3-transgenic mice with inducible and selective deletion of Foxp3⁺ cells are unable to form iTLS in lung allografts, and these mice acutely reject lung allografts. Collectively, we report that short-term, high-intensity and biased IL-2 pre-conditioning facilitates acceptance of vascularized and ventilated lung allografts without the need of immunosuppression, by inducing Foxp3-controlled iTLS formation within allografts.

Interleukin-2–based therapies in cancer

Molecular insights into the mechanism of beneficial and adverse effects of interleukin-2 (IL-2) have resulted in the development of improved IL-2 formulations with IL-2 receptor bias and tissue-targeting properties. Several of these compounds are currently in clinical development and are ushering IL-2 therapy into the current era of cancer immunotherapy.

Engineering IL-2 for immunotherapy of autoimmunity and cancer

Preclinical studies of the T cell growth factor activity of IL-2 resulted in this cytokine becoming the first immunotherapy to be approved nearly 30 years ago by the US Food and Drug Administration for the treatment of cancer. Since then, we have learnt the important role of IL-2 in regulating tolerance through regulatory T cells (Treg cells) besides promoting immunity through its action on effector T cells and memory T cells. Another pivotal event in the history of IL-2 research was solving the crystal structure of IL-2 bound to its tripartite receptor, which spurred the development of cell type-selective engineered IL-2 products. These new IL-2 analogues target Treg cells to counteract the dysregulated immune system in the context of autoimmunity and inflammatory disorders or target effector T cells, memory T cells and natural killer cells to enhance their antitumour responses. IL-2 biologics have proven to be effective in preclinical studies and clinical assessment of some is now underway. These studies will soon reveal whether engineered IL-2 biologics are truly capable of harnessing the IL-2-IL-2 receptor pathway as effective monotherapies or combination therapies for autoimmunity and cancer.

Natural products exert anti-tumor effects by regulating exosomal ncRNA

Currently, more than 60% of the approved anti-cancer drugs come from or are related to natural products. Natural products and exosomal non-coding RNAs (ncRNAs) exert anti-cancer effects through various regulatory mechanisms, which are of great research significance. Exosomes are a form of intercellular communication and contain ncRNAs that can act as intercellular signaling molecules involved in the metabolism of tumor cells. This review exemplifies some examples of natural products whose active ingredients can play a role in cancer prevention and treatment by regulating exosomal ncRNAs, with the aim of illustrating the mechanism of action of exosomal ncRNAs in cancer prevention and treatment. Meanwhile, the application of exosomes as natural drug delivery systems and predictive disease biomarkers in cancer prevention and treatment is introduced, providing research ideas for the development of novel anti-tumor drugs.

Developing a translational murine-to-canine pathway for an IL-2/agonist anti-CD40 antibody cancer immunotherapy

Human and canine sarcomas are difficult to treat soft tissue malignancies with an urgent need for new improved therapeutic options. Local recurrence rates for humans are between 10%-30%, and 30%-40% develop metastases. Outcomes for dogs with sarcoma vary with grade but can be similar. Pet dogs share the human environment and represent human cancer with genetic variation in hosts and tumours. We asked if our murine studies using genetically identical mice and cloned tumour cells were translatable to larger, genetically diverse domestic dogs with naturally occurring tumours, to (i) develop a canine cancer therapeutic, and (ii) to use as a translational pathway to humans. Our murine studies showed that intra-tumoral delivery of interleukin-2 (IL-2) plus an agonist anti-CD40 antibody (Ab) induces long-term curative responses ranging from 30% to 100%, depending on tumour type. We developed an agonist anti-canine-CD40 Ab and conducted a phase I dose finding/toxicology 3 + 3 clinical trial in dogs (n = 27) with soft tissue sarcomas on account of suitability for intratumoral injection and straightforward monitoring. Dogs were treated with IL-2 plus anti-CD40 antibody for 2 weeks. Three dose levels induced tumour regression with minimal side effects, measured by monitoring, haematological and biochemical assays. Importantly, our mouse and canine studies provide encouraging fundamental proof-of-concept data upon which we can develop veterinary and human immunotherapeutic strategies.

LAG-3xPD-L1 bispecific antibody potentiates antitumor responses of T cells through dendritic cell activation

Several preclinical studies demonstrate that antitumor efficacy of programmed cell death-1 (PD-1)/programmed death-ligand 1 (PD-L1) blockade can be improved by combination with other checkpoint inhibitors. Lymphocyte-activation gene 3 (LAG-3) is an inhibitory checkpoint receptor involved in T cell exhaustion and tumor immune escape. Here, we describe ABL501, a bispecific antibody targeting LAG-3 and PD-L1 in modulating immune cell responses against tumors. ABL501 that efficiently inhibits both LAG-3 and PD-L1 pathways enhances the activation of effector CD4+ and CD8+ T cells with a higher degree than a combination of single anti-LAG-3 and anti-PD-L1. The augmented effector T cell responses by ABL501 resulted in mitigating regulatory-T-cell-mediated immunosuppression. Mechanistically, the simultaneous binding of ABL501 to LAG-3 and PD-L1 promotes dendritic cell (DC) activation and tumor cell conjugation with T cells that subsequently mounts effective CD8+ T cell responses. ABL501 demonstrates its potent in vivo antitumor efficacy in a humanized xenograft model and with knockin mice expressing human orthologs. The immune profiling analysis of peripheral blood reveals an increased abundance of LAG-3hiPD-1hi memory CD4+ T cell subset in relapsed cholangiocarcinoma patients after gemcitabine plus cisplatin therapy, which are more responsive to ABL501. This study supports the clinical evaluation of ABL501 as a novel cancer immunotherapeutic, and a first-in-human trial has started (NCT05101109).

Type 2 immune predisposition results in accelerated neutrophil aging causing susceptibility to bacterial infection

Atopic individuals show enhanced type 2 immune cell responses and a susceptibility to infections with certain bacteria and viruses. Although patients with allergic diseases harbor normal counts of circulating neutrophils, these cells exert deficient effector functions. However, the underlying mechanism of this dysregulation of neutrophils remains ill defined. Here, we find that development, aging, and elimination of neutrophils are accelerated in mice with a predisposition to type 2 immunity, which, in turn, causes susceptibility to infection with several bacteria. Neutrophil-mediated immunity to bacterial infection was greatly decreased in mice with a genetic or induced bias to type 2 immunity. Abrogation of interleukin-4 (IL-4) receptor signaling in these animals fully restored their antibacterial defense, which largely depended on Ly6G⁺ neutrophils. IL-4 signals accelerated the maturation of neutrophils in the bone marrow and caused their rapid release to the circulation and periphery. IL-4-stimulated neutrophils aged more rapidly in the periphery, as evidenced by their phenotypic and functional changes, including their decreased phagocytosis of bacterial particles. Moreover, neutrophils from type 2 immune predisposed mice were eliminated at a higher rate by apoptosis and phagocytosis by macrophages and dendritic cells. Collectively, IL-4 signaling-mediated neutrophil aging constitutes an important adaptive deficiency in type 2 inflammation, contributing to recurrent bacterial infections.

Roles for macrophage-polarizing interleukins in cancer immunity and immunotherapy

Macrophages are the most abundant and one of the most critical cells of tumor immunity. They provide a bridge between innate and adaptive immunity through releasing cytokines into the tumor microenvironment (TME). A number of interleukin (IL) cytokine family members is involved in shaping the final phenotype of macrophages toward either a classically-activated pro-inflammatory M1 state with anti-tumor activity or an alternatively-activated anti-inflammatory M2 state with pro-tumor activity. Shaping TME macrophages toward the M1 phenotype or recovering this phenotypic state may offer a promising therapeutic approach in patients with cancer. Here, we focus on the impact of macrophage-polarizing ILs on immune cells and IL-mediated cellular cross-interactions within the TME. The key aim of this review is to define therapeutic schedules for addressing ILs in cancer immunotherapy based on their multi-directional impacts in such a milieu. Gathering more knowledge on this area is also important for defining adverse effects related to cytokine therapy and addressing them for reinforcing the efficacy of immunotherapy against cancer.

Addition of interleukin-2 overcomes resistance to neoadjuvant CTLA4 and PD1 blockade in ex vivo patient tumors

Neoadjuvant immunotherapy with anti-cytotoxic T lymphocyte-associated protein 4 (CTLA4) + anti-programmed cell death protein 1 (PD1) monoclonal antibodies has demonstrated remarkable pathological responses and relapse-free survival in ~80% of patients with clinically detectable stage III melanoma. However, about 20% of the treated patients do not respond. In pretreatment biopsies of patients with melanoma, we found that resistance to neoadjuvant CTLA4 + PD1 blockade was associated with a low CD4/interleukin-2 (IL-2) gene signature. Ex vivo, addition of IL-2 to CTLA4 + PD1 blockade induced T cell activation and deep immunological responses in anti-CTLA4 + anti-PD1-resistant human tumor specimens. In the 4T1.2 breast cancer mouse model of neoadjuvant immunotherapy, triple combination of anti-CTLA4 + anti-PD1 + IL-2 cured almost twice as many mice as compared with dual checkpoint inhibitor therapy. This improved efficacy was due to the expansion of tumor-specific CD8⁺ T cells and improved proinflammatory cytokine polyfunctionality of both CD4⁺ and CD8⁺ T effector cells and regulatory T cells. Depletion studies suggested that CD4⁺ T cells were critical for priming of CD8⁺ T cell immunity against 4T1.2 and helped in the expansion of tumor-specific CD8⁺ T cells early after neoadjuvant triple immunotherapy. Our results suggest that the addition of IL-2 can overcome resistance to neoadjuvant anti-CTLA4 + anti-PD1, providing the rationale for testing this combination as a neoadjuvant therapy in patients with early-stage cancer.

Combining bempegaldesleukin (CD122-preferential IL-2 pathway agonist) and NKTR-262 (TLR7/8 agonist) improves systemic antitumor CD8+ T cell cytotoxicity over BEMPEG+RT

Background

Tumor cell death caused by radiation therapy (RT) triggers antitumor immunity in part because dying cells release adjuvant factors that amplify and sustain dendritic cell and T cell responses. We previously demonstrated that bempegaldesleukin (BEMPEG: NKTR-214, an immunostimulatory IL-2 cytokine prodrug) significantly enhanced the antitumor efficacy of RT through a T cell-dependent mechanism. Because RT can induce either immunogenic or tolerogenic cell death, depending on various factors (radiation dose, cell cycle phase), we hypothesized that providing a specific immunogenic adjuvant, like intratumoral therapy with a novel toll-like receptor (TLR) 7/8 agonist, NKTR-262, would improve systemic tumor-specific responses through the activation of local innate immunity. Therefore, we evaluated whether intratumoral NKTR-262 combined with systemic BEMPEG treatment would elicit improved tumor-specific immunity and survival compared with RT combined with BEMPEG.

Methods

Tumor-bearing mice (CT26; EMT6) received BEMPEG (0.8 mg/kg; intravenously), RT (12 Gy × 1), and/or intratumoral NKTR-262 (0.5 mg/kg). Flow cytometry was used to evaluate CD4⁺ and CD8⁺ T cell responses in the blood and tumor 7 days post-treatment. The contribution of specific immune subsets was determined by depletion of CD4⁺, CD8⁺, or NK cells. CD8⁺ T cell cytolytic activity was determined by an in vitro CTL assay. Data are representative of 1–2 independent experiments (n=5–14/group) and statistical significance was determined by 1-way analysis of variance (ANOVA) or repeated measures ANOVA (p value cut-off of 0.05).

Results

BEMPEG+NKTR-262 significantly improved survival compared with BEMPEG+RT in a CD8⁺ T cell-dependent manner. Response to BEMPEG+NKTR-262 was characterized by a significant expansion of activated CD8⁺ T cells (GzmA⁺; Ki-67⁺; ICOS⁺; PD-1⁺) in the blood, which correlated with reduced tumor size (p<0.05). In the tumor, BEMPEG+NKTR-262 induced higher frequencies of GzmA⁺ CD8⁺ T cells exhibiting reduced expression of suppressive molecules (PD-1⁺), compared with BEMPEG+RT (p<0.05). Further, BEMPEG+NKTR-262 treatment induced greater tumor-specific CD8⁺ T cell cytolytic function than BEMPEG+RT.

Conclusions

BEMPEG+NKTR-262 therapy elicited more robust expansion of activated CD8⁺ T cells compared with BEMPEG+RT, suggesting that intratumoral TLR stimulation provides superior antigen presentation and costimulatory activity compared with RT. A clinical trial of BEMPEG+NKTR-262 for patients with metastatic solid tumors is in progress (NCT03435640).

Patients with systemic sclerosis show phenotypic and functional defects in neutrophils

BACKGROUND

Systemic sclerosis (SSc) is a multiorgan autoimmune disease characterized by inflammation, vascular modification, and progressive fibrosis of the skin and several visceral organs. Innate and adaptive immune cells, including myeloid, B and T cells, are believed to be central to the pathogenesis of SSc. However, the role and functional state of neutrophil granulocytes (neutrophils) are ill-defined in SSc.

METHODS

We performed a prospective study of neutrophils freshly isolated from SSc patients and healthy donors (HD) by measuring in these neutrophils (i) functional cell surface markers, including CD16, CD62L, CD66b, CD66c, CXCR1, CXCR2, and CXCR4; (ii) cytokine-activated intracellular signal transducer and activator of transcription (STAT) pathways, such as phosphorylated STAT3 (pSTAT3), pSTAT5, and pSTAT6; (iii) production of neutrophil extracellular traps (NET) and intracellular myeloperoxidase (MPO); and (iv) phagocytosis of bacteria by the neutrophils.

RESULTS

Neutrophils of SSc patients expressed lower CD16 and CD62L and higher pSTAT3 and pSTAT6 compared to HD. Moreover, neutrophils of SSc patients lacked CXCR1 and CXCR2, the receptors responding to the potent neutrophil chemoattractant CXCL8. Neutrophils of SSc patients were also deficient in MPO levels, NET formation, and phagocytosis of bacteria.

CONCLUSIONS

Neutrophils of patients with SSc display several functional defects affecting cell migration, NET formation, and phagocytosis of bacteria.

Coupling programmed cell death 1-positive tumor-infiltrating T cells with anti-programmed cell death 1 antibody improves the efficacy of adoptive T-cell therapy

BACKGROUND AIMS

Adoptive cell therapy (ACT) with tumor-infiltrating lymphocytes (TILs) has shown great success in clinical trials. Programmed cell death 1 (PD-1)-expressing TILs show high specificity to autologous tumor cells. However, limited therapeutic efficiency is observed as a result of the tumor immune microenvironment (TIME).

METHODS

Coupling PD-1+ex vivo-derived TILs with a monoclonal antibody against anti-PD-1 (aPD-1) reinvigorated the anti-tumor response of TILs against solid tumor without altering their high tumor targeting ability.

RESULTS

Using a melanoma-bearing mouse model, PD-1+ TILs blocked with aPD-1 (PD-1+ TILs-aPD-1) exhibited a high capability for tumor targeting as well as improved anti-tumor response in TIME. Tumor growth was substantially delayed in the mice treated with PD-1+ TILs-aPD-1.

CONCLUSIONS

The strategy utilizing TIL therapy coupled with immune checkpoint antibodies may extend to other therapeutic targets of ACT.

Engineering a safe monoclonal anti-human IL-2 that is effective in a murine model of food allergy and asthma

BACKGROUND

Regulatory T cells (Tregs) are known to protect against allergies. Moreover, the decrease in the frequency and efficiency of Tregs amplifies allergic symptoms.

AIM

This study investigated whether expanding Tregs in vivo with an IL-2/IL-2 antibody complex could be safe, well tolerated and efficient in a therapeutic setting in allergies.

METHODS

We produced an anti-IL-2 antibody (1C6) and demonstrated that when it is complexed to human IL-2, it increases IL-2 efficiency to induce Tregs in vivo without any detectable side effects. Furthermore, the IL-2/1C6 complex induces an increase in Helios expression by Tregs, suggesting that it not only elevated Treg numbers but also boosted their functions. Using mouse models of house-dust-mite-induced airway inflammation and wheat-gliadin-induced food allergies, we investigated the therapeutic potential of the IL-2/1C6 complex in allergies.

RESULTS

IL-2/1C6 treatment significantly reduced allergic symptoms, specific IgE production, the adaptive immune response and tissue damage. Interestingly, IL-2/1C6 treatment modulated innate lymphoid cells by increasing ILC2s in asthma and decreasing ILC3s in food allergies.

CONCLUSION

In conclusion,complexed IL-2/anti-IL-2 may restore Treg numbers and function in respiratory and food allergies, thereby improving allergic markers and symptoms. Our IL-2/anti-IL-2 complex offers new hope for reestablishing immune tolerance in patients with allergies.

CCR7-guided neutrophil redirection to skin-draining lymph nodes regulates cutaneous inflammation and infection

Neutrophils are the first nonresident effector immune cells that migrate to a site of infection or inflammation; however, improper control of neutrophil responses can cause considerable tissue damage. Here, we found that neutrophil responses in inflamed or infected skin were regulated by CCR7-dependent migration and phagocytosis of neutrophils in draining lymph nodes (dLNs). In mouse models of Toll-like receptor-induced skin inflammation and cutaneous Staphylococcus aureus infection, neutrophils migrated from the skin to the dLNs via lymphatic vessels in a CCR7-mediated manner. In the dLNs, these neutrophils were phagocytosed by lymph node-resident type 1 and type 2 conventional dendritic cells. CCR7 up-regulation on neutrophils was a conserved mechanism across different tissues and was induced by a broad range of microbial stimuli. In the context of cutaneous immune responses, disruption of CCR7 interactions by selective CCR7 deficiency of neutrophils resulted in increased antistaphylococcal immunity and aggravated skin inflammation. Thus, neutrophil homing to and clearance in skin-dLNs affects cutaneous immunity versus pathology.

Uncovering the Depths of the Human Proteome: Antibody-based Technologies for Ultrasensitive Multiplexed Protein Detection and Quantification

Probing the human proteome in tissues and biofluids such as plasma is attractive for biomarker and drug target discovery. Recent breakthroughs in multiplex, antibody-based, proteomics technologies now enable the simultaneous quantification of thousands of proteins at as low as sub fg/ml concentrations with remarkable dynamic ranges of up to 10-log. We herein provide a comprehensive guide to the methodologies, performance, technical comparisons, advantages, and disadvantages of established and emerging technologies for the multiplexed ultrasensitive measurement of proteins. Gaining holistic knowledge on these innovations is crucial for choosing the right multiplexed proteomics tool for applications at hand to critically complement traditional proteomics methods. This can bring researchers closer than ever before to elucidating the intricate inner workings and cross talk that spans multitude of proteins in disease mechanisms.

Identification of a Kupffer cell subset capable of reverting the T cell dysfunction induced by hepatocellular priming

Kupffer cells (KCs) are highly abundant, intravascular, liver-resident macrophages known for their scavenger and phagocytic functions. KCs can also present antigens to CD8⁺ T cells and promote either tolerance or effector differentiation, but the mechanisms underlying these discrepant outcomes are poorly understood. Here, we used a mouse model of hepatitis B virus (HBV) infection, in which HBV-specific naive CD8⁺ T cells recognizing hepatocellular antigens are driven into a state of immune dysfunction, to identify a subset of KCs (referred to as KC2) that cross-presents hepatocellular antigens upon interleukin-2 (IL-2) administration, thus improving the antiviral function of T cells. Removing MHC-I from all KCs, including KC2, or selectively depleting KC2 impaired the capacity of IL-2 to revert the T cell dysfunction induced by intrahepatic priming. In summary, by sensing IL-2 and cross-presenting hepatocellular antigens, KC2 overcome the tolerogenic potential of the hepatic microenvironment, suggesting new strategies for boosting hepatic T cell immunity.

Profound dysregulation of T cell homeostasis and function in patients with severe COVID-19

BACKGROUND

Coronavirus disease 2019 (COVID-19) is caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and shows a broad clinical presentation ranging from asymptomatic infection to fatal disease. A very prominent feature associated with severe COVID-19 is T cell lymphopenia. However, homeostatic and functional properties of T cells are ill-defined in COVID-19.

METHODS

We prospectively enrolled individuals with mild and severe COVID-19 into our multicenter cohort and performed a cross-sectional analysis of phenotypic and functional characteristics of T cells using 40-parameter mass cytometry, flow cytometry, targeted proteomics, and functional assays.

RESULTS

Compared with mild disease, we observed strong perturbations of peripheral T cell homeostasis and function in severe COVID-19. Individuals with severe COVID-19 showed T cell lymphopenia and redistribution of T cell populations, including loss of naïve T cells, skewing toward CD4+ T follicular helper cells and cytotoxic CD4+ T cells, and expansion of activated and exhausted T cells. Extensive T cell apoptosis was particularly evident with severe disease and T cell lymphopenia, which in turn was accompanied by impaired T cell responses to several common viral antigens. Patients with severe disease showed elevated interleukin-7 and increased T cell proliferation. Furthermore, patients sampled at late time points after symptom onset had higher T cell counts and improved antiviral T cell responses.

CONCLUSION

Our study suggests that severe COVID-19 is characterized by extensive T cell dysfunction and T cell apoptosis, which is associated with signs of homeostatic T cell proliferation and T cell recovery.