IL-15 in T-Cell Responses and Immunopathogenesis

Interleukin-enhanced CAR-engineered immune cells in tumor immunotherapy: current insights and future perspectives

Despite the remarkable clinical success of chimeric antigen receptor (CAR)-T cell therapy in hematologic malignancies, the therapeutic efficacy of conventional second-generation CAR-T cells in treating solid tumors remains suboptimal, primarily due to three major biological barriers: (1) the immunosuppressive tumor microenvironment (TME), (2) inadequate tumor infiltration capacity, and (3) T cell exhaustion mechanisms. To overcome these limitations, innovative fourth-generation "armored" CAR-T cell platforms have been engineered with integrated cytokine-secreting modules designed to potentiate anti-tumor responses through localized immunomodulation. These advanced cellular therapeutics achieve targeted delivery of various immunostimulatory cytokines directly within the TME, thereby orchestrating three critical therapeutic effects: (I) remodeling of the immunosuppressive niche, (II) enhancement of immune cell persistence, and (III) neutralization of immunosuppressive signaling networks. This comprehensive review systematically examines the translational applications of cytokine-secreting CAR-engineered immune cells, including CAR-T, CAR-NK, and CAR-iNKT cell platforms, in solid tumor immunotherapy, with particular emphasis on multiple classes of immunomodulatory cytokines that enhance cytotoxic potential, promote immune cell survival, and counteract TME-mediated immunosuppression. We critically evaluate preclinical and clinical evidence demonstrating the therapeutic efficacy of cytokine-armed CAR-engineered cells across various tumor models, including hematological malignancies, glioblastoma, and neuroblastoma. Furthermore, this review addresses current translational challenges, particularly cytokine-associated toxicity profiles and innovative strategies for achieving spatiotemporal control of cytokine release, while discussing their potential implications for advancing clinical outcomes in solid tumor immunotherapy.

Engineered Mycobacterium smegmatis expressing anti-PD-L1/IL-15 immunocytokine induces and activates specific antitumor immunity

BACKGROUND

Immune checkpoint inhibitors and cytokines have revolutionized tumor treatment but are still limited by dose-dependent toxicity and efficacy. In situ vaccine platforms based on intelligent microbes are promising therapeutic strategies that sustainably deliver drugs locally without causing severe systemic risks.

METHODS

In this study, we have innovatively engineered a non-pathogenic, adjuvant-acting Mycobacterium smegmatis (M. smegmatis) that co-expresses a programmed cell death-ligand 1 (PD-L1) inhibitor and an interleukin-15 (IL-15) cytokine complex containing the interleukin-15 receptor alpha (IL-15Rα) sushi domain (Ms-PDL1scfv-IL15).

RESULTS

We demonstrate that the fusion protein of PD-L1 inhibitor and IL-15 cytokine systemically binds mouse or human PD-L1 and maintains IL-15 stimulatory activity. The bifunctional Ms-PDL1scfv-IL15 overcomes resistance to PD-L1 blockade, recruits numerous immune cells in situ, induces dendritic cells (DCs) maturation, initiates the M1 antitumor polarization of macrophages, increases the proliferation and activation of natural killer cells and tumor-infiltrating CD8+ T cells, inhibits regulatory T cells, elicits abscopal effects, stimulates rapid tumor regression, prevents metastasis, and leads to long-term survival in several syngeneic tumor mouse models. We also found that the combination of Ms-PDL1scfv-IL15 with granulocyte-macrophage colony-stimulating factor (GM-CSF) synergistically stunted the tumor progress and stasis. Moreover, intratumoral administration of Ms-PDL1scfv-IL15 can capture tumor antigen fragments, and boost DCs presentation of antigens, which remarkably initiates tumor antigen-specific immune response, leading to durable tumor regression and specific antitumor immunity.

CONCLUSION

In summary, the engineered M. smegmatis can recruit and activate innate and adaptive antitumor immune responses, offering a potent cancer immunotherapy strategy to treat patients with cold tumors or resistance to checkpoint blockade.

Controversies and insights into cytokine regulation of neurogenesis and behavior in adult rodents

Adult learning, memory, and social interaction partially depend on neurogenesis in two regions: the hippocampus and the subventricular zone. There is evidence that the immune system is important for these processes in pathological situations, but there is no review of its role in non-pathological or near-physiological conditions. Although further research is warranted in this area, some conclusions can be drawn. Intrusive LyC6hi monocytes and autoreactive CD4+ T cells have a positive impact on neurogenesis and behavior, but the latter are deleterious if specific to external antigens. Mildly activated microglia play a crucial role in promoting these processes, by eliminating apoptotic neuronal progenitors and producing low levels of interleukins, which increase if the cells are activated, leading to inhibition of neurogenesis. Chemokines are poorly studied, but progenitor cells and neurons express their receptors, which appear important for migration and maturation. The few works that jointly analyzed neurogenesis and behavior showed congruent effects of immune cells and cytokines. In conclusion, the immune system components -mostly local- seem of utmost importance for the control of behavior under non-pathological conditions.

γδT cells, a key subset of T cell for cancer immunotherapy

γδT cells represent a unique and versatile subset of T cells characterized by the expression of T-cell receptors (TCRs) composed of γ and δ chains. Unlike conventional αβT cells, γδT cells do not require major histocompatibility complex (MHC)-dependent antigen presentation for activation, enabling them to recognize and respond to a wide array of antigens, including phosphoantigens, stress-induced ligands, and tumor-associated antigens. While γδT cells are relatively rare in peripheral blood, they are enriched in peripheral tissues such as the skin, intestine, and lung. These cells play a crucial role in tumor immunotherapy by exerting direct cytotoxicity through the production of inflammatory cytokines (e.g., interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), and interleukin-17 (IL-17)) and cytotoxic molecules (e.g., perforin and granzyme). Recent advances in γδT cell research have elucidated their mechanisms of tumor recognition, including the detection of phosphoantigens and stress-induced ligands like MICA (MHC class I polypeptide-related sequence A), MICB (MHC class I polypeptide-related sequence B), and ULBP (UL16-binding protein). Furthermore, various strategies to enhance γδT cell-based tumor immunotherapy have been developed, such as in vitro expansion using phosphoantigen-based therapies, cytokine stimulation, and chimeric antigen receptor (CAR)-γδT cell engineering. These advancements have shown promising results in both preclinical and clinical settings, paving the way for γδT cells to become a powerful tool in cancer immunotherapy. This review highlights the key mechanisms, functions, and strategies to harness the potential of γδT cells for effective tumor immunotherapy.

Metabolic Signaling as a Driver of T Cell Aging

Aging significantly diminishes T cell immunity, increasing susceptibility to infections and reducing vaccine efficacy in older individuals. Metabolism plays a key role in T cell function, shaping their energy requirements, activation, and differentiation. Recent studies highlight altered metabolic signaling as a pivotal factor in T cell aging, influencing the ability of T cells to maintain quiescence, respond to activation, and differentiate into functional subsets. Aberrant metabolic pathways disrupt the quiescence of aged T cells and skew their differentiation toward short-lived, pro-inflammatory effector T cells while hindering the generation of long-lived memory and T follicular helper cells. These changes contribute to a hyper-inflammatory state, exacerbate chronic low-grade inflammation, and compromise immune homeostasis. In this review, we explore how metabolic signaling is altered during T cell aging and the resulting functional impacts. We also discuss therapeutic approaches aimed at restoring proper T cell differentiation, improving vaccine responses, and rejuvenating immune function in older populations.

Sensory neuroimmune signaling in the pathogenesis of Stevens-Johnson syndrome and toxic epidermal necrolysis

BACKGROUND

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening cutaneous reactions often triggered by medications. While the involvement of CD8+ T cells causing keratinocyte death is well recognized, the contribution of neural elements to the persistent skin inflammation has been largely overlooked.

OBJECTIVE

We investigated the potential neuroimmune regulation in SJS/TEN.

METHODS

Unbiased single-cell RNA sequencing and flow cytometry were performed using circulating CD8+ T cells from healthy controls and patients with SJS/TEN. ELISA and LEGENDplex assays were respectively used to detect neuropeptides and inflammatory mediators. Skin tissues were examined by immunofluorescence staining for neuropeptide-associated nerves and cytokine receptors. Calcium imaging, Smart-seq, and a 3-D skin model were used for cultured human CD8+ T cells.

RESULTS

Unbiased RNA sequencing revealed an upregulation of the receptor for neuropeptide calcitonin gene-related peptide (CGRP), known as RAMP1, in effector CD8+ T cells in SJS/TEN. Increased CGRP+ nerve fibers and CGRP levels, along with upregulated IL-15R and IL-18R on CD8+ T cells, were displayed in the affected skin of SJS/TEN. The CGRP-RAMP1 axis was necessary and sufficient to enhance receptors for IL-15 and IL-18 and cytotoxic activities in CD8+ T cells, ultimately resulting in keratinocyte apoptosis. Calcium influx was detected in CGRP-stimulated CD8+ T cells. HCN2, a hyperpolarization-activated cation channel, was required for this process and the subsequent cytotoxic effects.

CONCLUSIONS

Our study highlights the role of neural elements in regulating CD8+ T-cell-mediated inflammatory responses and provides new potential translational targets to improve the outcomes of severe cutaneous drug reactions.

Age influences the circulating immune profile in pediatric sepsis

Background

The immune response changes as patients age, yet studies on the immune dysregulation of sepsis often do not consider age as a key variable.

Objective

We hypothesized that age would influence the immune response in septic children and that there would be a distinct variation in the immune profile in healthy children and children with either sepsis, uncomplicated infection, or acute organ dysfunction without infection. We characterized the circulating immune profile of children presenting to our tertiary care children's hospital.

Methods

This investigation was a prospective, observational cohort study that enrolled patients from July 2020 - September 2022. Patients were included if they were < 21 years, admitted to the PICU, and received fluid resuscitation and antibiotics. Peripheral blood mononuclear cells were isolated from samples collected on PICU day 1.

Results

Eighty patients were enrolled. Children with sepsis had more regulatory CD4+ T cells and memory CD4+ T cells and less CD4+IL-10+ and CD8+T-bet+ T cells than healthy children. After ex vivo stimulation, sepsis samples had less of a reduction in CD4+ T cells producing IL-10 than healthy controls. Memory CD4+ T cells and regulatory CD4+ T cells were positively associated with age in sepsis alone.

Conclusion

A regulatory T cell failure may contribute to pediatric sepsis pathogenesis. Age is an important variable affecting sepsis-associated immune dysregulation and memory T cells in peripheral circulation correlate with age in sepsis alone.

Anti-CD8/IL-15 (N72D)/sushi fusion protein: A promising strategy for improvement of cancer immunotherapy

BACKGROUND

To overcome the limitations of IL-15 and to improve the efficacy of IL-15 in immunotherapy, several strategies have been introduced.

OBJECTIVE

The objective of this study was to generate and evaluate a novel anti-CD8/IL-15 (N72D)/Sushi fusion protein with the potential to target CD8+ T cells and enhance functionality of CD8+ T cells against tumor cells.

METHODS

In this connection, a novel fusokine that contains IL-15(N72D), a Sushi domain, and anti-CD8 single-chain fragment variable (scFv) was designed. The size accuracy and binding potency of the isolated protein were assessed using western blotting and indirect surface staining. Following purification, the potential function of the anti-CD8/IL-15(N72D)/Sushi fusion protein in the induction of proliferation and cytotoxicity of CD8+ T cells was evaluated.

RESULTS

In-silico analysis revealed that fusokine is structurally stable, correctly folded and can interact with the CD8 co-receptor. Both fusokine and IL-15(N72D)/Sushi were produced in CHO-S cell line with a final concentration of 18.43 mg/l and 12.64 mg/l respectively. Fusokine bound to 97.6 % of CD8+ T cells and significantly induced T cell proliferation and cytotoxic potential in peripheral blood mononuclear cells (PBMCs) in a time dependent manner. Compared to both the control and the IL-15 (N72D)/sushi treated groups, fusokine showed superior potential in CD8+ T cell functionality.

CONCLUSION

Anti-CD8/IL-15(N72D)/Sushi has the ability to effectively target CD8+ T cells, promote lymphocyte proliferation and induce cytotoxicity against tumor cells. Due to its promising properties, it could be considered as a new potential immunotherapy approach.

Specific plasma biomarker signatures associated with patients undergoing surgery for back pain

BACKGROUND CONTEXT

Intervertebral disc degeneration (IDD) affects numerous people worldwide. The role of inflammation is increasingly recognized but remains incompletely resolved. Peripheral molecules could access neovascularized degenerated discs and contribute to the ongoing pathology.

PURPOSE

To assess a large array of plasma molecules in patients with IDD to identify biomarkers associated with specific spinal pathologies and prognostic biomarkers for the surgery outcome.

DESIGN

Prospective observational study combining clinical data and plasma measures.

PATIENT SAMPLE

Plasma samples were collected just before surgery. Extensive clinical data (age, sex, smoking status, Modic score, glomerular filtration rate, etc.) were extracted from clinical files from 83 patients with IDD undergoing spine surgery.

OUTCOME MEASURES

Recovery 2 months postsurgery as assessed by the treating neurosurgeon.

METHODS

Over 40 biological molecules were measured in patients' plasma using multiplex assays. Statistical analyses were performed to identify associations between biological and clinical characteristics (age, sex, Body Mass Index (BMI), smoking status, herniated disc, radiculopathy, myelopathy, stenosis, MODIC score, etc.) and plasma levels of biological molecules.

RESULTS

Plasma levels of Neurofilament Light chain (NfL) were significantly elevated in patients with myelopathy and spinal stenosis compared to herniated disc. Plasma levels of C- reactive protein (CRP), Neurofilament Light chain (NfL), and Serum Amyloid A (SAA) were negatively associated, while CCL22 levels were positively associated with an efficient recovery 2 months postsurgery.

CONCLUSIONS

Our results show that CRP and CCL22 plasma levels combined with the age of the IDD patient can predict the 2-month postsurgery recovery (Area Under the Curve [AUC]=0.883). Moreover, NfL could become a valuable monitoring tool for patients with spinal cord injuries.

Lung cancer organoid-based drug evaluation models and new drug development application trends

Lung cancer is a malignant tumor with high incidence and mortality rates in both men and women worldwide. Although anticancer drugs are prescribed to treat lung cancer patients, individual responses to these drugs vary, making it crucial to identify the most suitable treatment for each patient. Therefore, it is necessary to develop an anticancer drug efficacy prediction model that can analyze drug efficacy before patient treatment and establish personalized treatment strategies. Unlike two-dimensional (2D) cultured lung cancer cells, lung cancer organoid (LCO) models have a three-dimensional (3D) structure that effectively mimics the characteristics and heterogeneity of lung cancer cells. Lung cancer patient-derived organoids (PDOs) also have the advantage of recapitulating histological and genetic characteristics similar to those of patient tissues under in vitro conditions. Due to these advantages, LCO models are utilized in various fields, including cancer research, and precision medicine, and are especially employed in various new drug development processes, such as targeted therapies and immunotherapy. LCO models demonstrate potential applications in precision medicine and new drug development research. This review discusses the various methods for implementing LCO models, LCO-based anticancer drug efficacy analysis models, and new trends in lung cancer-targeted drug development.

Mapping enhancer-gene regulatory interactions from single-cell data

Mapping enhancers and their target genes in specific cell types is crucial for understanding gene regulation and human disease genetics. However, accurately predicting enhancer-gene regulatory interactions from single-cell datasets has been challenging. Here, we introduce a new family of classification models, scE2G, to predict enhancer-gene regulation. These models use features from single-cell ATAC-seq or multiomic RNA and ATAC-seq data and are trained on a CRISPR perturbation dataset including >10,000 evaluated element-gene pairs. We benchmark scE2G models against CRISPR perturbations, fine-mapped eQTLs, and GWAS variant-gene associations and demonstrate state-of-the-art performance at prediction tasks across multiple cell types and categories of perturbations. We apply scE2G to build maps of enhancer-gene regulatory interactions in heterogeneous tissues and interpret noncoding variants associated with complex traits, nominating regulatory interactions linking INPP4B and IL15 to lymphocyte counts. The scE2G models will enable accurate mapping of enhancer-gene regulatory interactions across thousands of diverse human cell types.

Racial Disparities in Plasma Cytokine and Microbiome Profiles

BACKGROUND

Many health issues prevalent in African American (AA) populations are associated with chronic inflammation and related health conditions, including autoimmune diseases, infectious diseases, neurologic disorders, metabolic syndromes, and others. The current study aims to understand plasma microbiome translocation as a potential trigger for chronic inflammation.

METHODS

In this study, 16 Caucasian American (CA) and 22 African American (AA) healthy individuals were recruited. Microbial DNA was isolated from the plasma samples and sequenced via microbial 16S rRNA V3-4 sequencing. The plasma levels of 33 cytokines and chemokines were evaluated. The proinflammatory microbiomes were verified using human THP-1 cells in vitro.

RESULTS

The plasma levels of IL-6, IL-15, MIP-1α, MIP-1β, and MIP-3α were higher in the AA people, whereas IL-1α and IL-27 were elevated in the CA people. The plasma microbiomes exhibited eight bacterial genera/phyla differentially enriched in the CA and AA people. Given the critical role of IL-6 in chronic inflammation and associated diseases, we identified five bacteria genera significantly associated with IL-6. The abundance of Actinomyces was positively correlated with the plasma IL-6 level (r = 0.41, p = 0.01), while the abundance of Kurthia (r = -0.34, p = 0.04), Noviherbaspirillum (r = -0.34, p = 0.04), Candidatus Protochlamydia (r = -0.36, p = 0.03), and Reyranella (r = -0.39, p = 0.02) was negatively correlated with this. Finally, the THP-1 cells treated with heat-killed bacteria produced higher levels of IL-6 in vitro in response to the Actinomyces species compared to the species in the genus either uncorrelated or negatively correlated with IL-6.

CONCLUSIONS

This is the first study to report potential blood microbiome translocation as a driver for persistently elevated IL-6 levels in the periphery in healthy AA versus CA people. Understanding the plasma microbiome linked to the IL-6 levels in people with different racial backgrounds is essential to unraveling the therapeutic approaches to improve precision medicine.