Bi-Specific Killer Cell Engager Enhances NK Cell Activity against Interleukin-13 Receptor Alpha-2 Positive Gliomas

NK Cell and Monocyte Dysfunction in Multisystem Inflammatory Syndrome in Children

Multisystem inflammatory syndrome in children (MIS-C) is a severe complication of SARS-CoV-2 infection characterized by multiorgan involvement and inflammation. Testing of cellular function ex vivo to understand the aberrant immune response in MIS-C is limited. Despite strong Ab production in MIS-C, SARS-CoV-2 nucleic acid testing can remain positive for 4-6 wk postinfection. Therefore, we hypothesized that dysfunctional cell-mediated Ab responses downstream of Ab production may be responsible for delayed clearance of viral products in MIS-C. In MIS-C, monocytes were hyperfunctional for phagocytosis and cytokine production, whereas NK cells were hypofunctional for both killing and cytokine production. The decreased NK cell cytotoxicity correlated with an NK exhaustion marker signature and systemic IL-6 levels. Potentially providing a therapeutic option, cellular engagers of CD16 and SARS-CoV-2 proteins were found to rescue NK cell function in vitro. Taken together, our results reveal dysregulation in Ab-mediated cellular responses of myeloid and NK cells that likely contribute to the immune pathology of this disease.

Current Developments in NK Cell Engagers for Cancer Immunotherapy: Focus on CD16A and NKp46

NK cells are specialized immune effector cells crucial for triggering immune responses against aberrant cells. Although recent advancements have concentrated on creating or releasing T-cell responses specific to tumor Ags, the clinical advantages of this approach have been limited to certain groups of patients and tumor types. This emphasizes the need for alternative strategies. One pioneering approach involves broadening and enhancing anti-tumor immune responses by targeting innate immunity. Consequently, the advent of bi-, tri-, and multi-specific Abs has facilitated the advancement of targeted cancer immunotherapies by redirecting immune effector cells to eradicate tumor cells. These Abs enable the simultaneous binding of surface Ags on tumor cells and the activation of receptors on innate immune cells, such as NK cells, with the ability to facilitate Ab-dependent cellular cytotoxicity to enhance their immunotherapeutic effectiveness in patients with solid tumors. Here, we review the recent advances in NK cell engagers (NKCEs) focusing on NK cell-activating receptors CD16A and NKp46. In addition, we provide an overview of the ongoing clinical trials investigating the safety, efficacy, and potential of NKCEs.

Prospective Molecular Targets for Natural Killer Cell Immunotherapy against Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most common type of primary malignant brain tumor and has a dismal overall survival rate. To date, no GBM therapy has yielded successful results in survival for patients beyond baseline surgical resection, radiation, and chemotherapy. Immunotherapy has taken the oncology world by storm in recent years and there has been movement from researchers to implement the immunotherapy revolution into GBM treatment. Natural killer (NK) cell-based immunotherapies are a rising candidate to treat GBM from multiple therapeutic vantage points: monoclonal antibody therapy targeting tumor-associated antigens (TAAs), immune checkpoint inhibitors, CAR-NK cell therapy, Bi-specific killer cell engagers (BiKEs), and more. NK therapies often focus on tumor antigens for targeting. Here, we reviewed some common targets analyzed in the fight for GBM immunotherapy relevant to NK cells: EGFR, HER2, CD155, and IL-13Rα2. We further propose investigating the Lectin-like Transcript 1 (LLT1) and cell surface proliferating cell nuclear antigen (csPCNA) as targets for NK cell-based immunotherapy.

Glioblastoma stem cell metabolism and immunity

Despite enormous efforts being invested in the development of novel therapies for brain malignancies, there remains a dire need for effective treatments, particularly for pediatric glioblastomas. Their poor prognosis has been attributed to the fact that conventional therapies target tumoral cells, but not glioblastoma stem cells (GSCs). GSCs are characterized by self-renewal, tumorigenicity, poor differentiation, and resistance to therapy. These characteristics represent the fundamental tools needed to recapitulate the tumor and result in a relapse. The mechanisms by which GSCs alter metabolic cues and escape elimination by immune cells are discussed in this article, along with potential strategies to harness effector immune cells against GSCs. As cellular immunotherapy is making significant advances in a variety of cancers, leveraging this underexplored reservoir may result in significant improvements in the treatment options for brain malignancies.

Harnessing immune cells to eliminate HIV reservoirs

PURPOSE OF REVIEW

Despite decades of insights about how CD8 + T cells and natural killer (NK) cells contribute to natural control of infection, additional hurdles (mutational escape from cellular immunity, sequence diversity, and hard-to-access tissue reservoirs) will need to be overcome to develop a cure. In this review, we highlight recent findings of novel mechanisms of antiviral cellular immunity and discuss current strategies for therapeutic deisgn.

RECENT FINDINGS

Of note are the apparent converging roles of viral antigen-specific MHC-E-restricted CD8 + T cells and NK cells, interleukin (IL)-15 biologics to boost cytotoxicity, and broadly neutralizing antibodies in their native form or as anitbody fragments to neutralize virus and engage cellular immunity, respectively. Finally, renewed interest in myeloid cells as relevant viral reservoirs is an encouraging sign for designing inclusive therapeutic strategies.

SUMMARY

Several studies have shown promise in many preclinical models of disease, including simian immunodeficiency virus (SIV)/SHIV infection in nonhuman primates and HIV infection in humanized mice. However, each model comes with its own limitations and may not fully predict human responses. We eagerly await the results of clinical trails assessing the efficacy of these strategies to achieve reductions in viral reservoirs, delay viral rebound, or ultimately elicit immune based control of infection without combination antiretroviral therapy (cART).

Expression of Interleukin-13 Receptor Alpha 2 in Brainstem Gliomas

The objective of this study was to investigate IL13Ra2 expression in brainstem glioma (BSG) and its correlation with key markers, functions, and prognostic implications, evaluating its therapeutic potential. A total of 80 tumor samples from BSG patients were analyzed. Multiplex immunofluorescence was used to examine six markers-IL13Ra2, H3.3K27M, CD133, Ki67, HLA-1, and CD4-establishing relationships between IL13Ra2 and these markers. Survival analysis, employing Kaplan-Meier and Cox proportional hazard regression models, encompassed 66 patients with complete follow-up. RNA-Seq data from a previously published study involving 98 patients were analyzed using the DESeq2 library to determine differential gene expression between groups. Gene Ontology (GO) enrichment and single-sample gene set enrichment analysis (ssGSEA) via the clusterProfiler library were used to delineate the gene functions of differentially expressed genes (DEGs). Nearly all the BSG patients displayed varying IL13Ra2 expression, with 45.0% (36/80) exhibiting over a 20% increase. Elevated IL13Ra2 levels were notably observed in pontine gliomas, diffuse intrinsic pontine gliomas (DIPGs), H3F3A-mutant gliomas, and WHO IV gliomas. IL13Ra2 expression was strongly correlated with H3.3K27M mutant protein, Ki67, and CD133. Patients with IL13Ra2 expression >20% showed shorter overall survival compared to those with ≤20% IL13Ra2 expression. The Cox proportional hazard regression model identified H3F3A mutations, rather than IL13Ra2 expression, as an independent prognostic factor. Analysis of RNA-Seq data from our prior cohort confirmed IL13Ra2's correlation with H3.3, CD133, and Ki67 levels. Widespread IL13Ra2 expression in BSG, particularly elevated in the H3F3A mutant group, was strongly correlated with H3F3A mutations, increased proliferation, and heightened tumor stemness. IL13Ra2 represents a promising therapeutic target for BSGs, potentially benefiting patients with H3K27M mutations, DIPGs, WHO Grade IV, and pontine location-specific BSGs, particularly those with H3K27M mutations.