Anti-cancer pro-inflammatory effects of an IgE antibody targeting the melanoma-associated antigen chondroitin sulfate proteoglycan 4

Physiochemical and functional evaluation of the first-in-class anti-cancer IgE antibody drug, MOv18, through process development and good manufacturing practice production

Antibodies used for cancer therapy are monoclonal IgGs, but tumor-targeting IgE antibodies have shown enhanced effector cell potency against cancer in preclinical models. Research-grade recombinant IgE antibodies have been generated and studied for several decades. The recent Phase 1 clinical trial of the first-in-class MOv18 IgE, however, necessitated the inaugural process development and scaled manufacture of a recombinant IgE to clinical quality standards. During the process development and scaled Good Manufacturing Practice production, we demonstrate the retention of glycosylation state, biophysical profile, and functional characteristics of MOv18 IgE, including Fc-mediated mast cell degranulation and tumor cell killing. Assessment of manufacturing parameters shows expected pH, purity, concentration, and stability properties, as well as below threshold levels of known biological manufacturing contaminants. We confirm the suitability of the pipeline described for generating intact, functionally active, clinical-grade material for this novel therapeutic class as an Investigational Medicinal Product (IMP), with comparable characteristics to the original research-grade antibody. Furthermore, we screened patient blood ex vivo for potential type I hypersensitivity reaction to MOv18 IgE, using the basophil activation test, to identify patients not predicted to be hypersensitive to MOv18 IgE administration. This study supports the production of functionally active clinical grade (IMP) recombinant IgE and paves the way for the development of a new therapeutic antibody class for a range of antigenic specificities and disease settings.

Clinical evaluation of HuDo-CSPG4 DNA electroporation as adjuvant treatment for canine oral malignant melanoma: comparison of two vaccination protocols

Canine oral malignant melanoma (OMM) is an aggressive, spontaneously occurring tumor carrying a poor to guarded prognosis and relatively limited therapeutic strategies. In this landscape, chondroitin sulfate proteoglycan (CSPG)4 represents a promising immunotherapeutic target. The objective of this bi-center prospective study was to examine the clinical outcome of OMM-bearing dogs treated with surgery and adjuvant electroporation using a DNA vaccine (HuDo-CSPG4) encoding both human (Hu) and canine (Do) portions of CSPG4 through two different vaccination protocols. Dogs with stage I-III surgically resected CSPG4-positive OMM underwent HuDo-CSPG4 plasmid electroporation starting at the 3rd-4th post-operative week; electrovaccination was repeated after 2 weeks. In protocol 1, electrovaccination was then delivered monthly while in protocol 2, electrovaccination was performed monthly four additional times followed by semestral boosters. The survival rates of HuDo-CSPG4-vaccinated dogs were estimated and compared with a control group treated with surgery alone. Significantly longer overall survival times were observed in HuDo-CSPG4 vaccinated dogs as compared with non-vaccinated controls. Dogs receiving protocol 2 showed similar outcomes to those of dogs undergoing protocol 1, despite fewer vaccinations. The comparable humoral response against CSPG4 resulting from the administration of protocol 1 and 2 appears to have similar clinical relevance, highlighting protocol 2 as the optimal vaccination schedule.

Hybrid IgE-IgG1 antibodies (IgEG): a new antibody class that combines IgE and IgG functionality

IgG-based anti-cancer therapies have achieved promising clinical outcomes, but, especially for patients with solid tumors, response rates vary. IgE antibodies promote distinct immune responses compared to IgG and have shown anti-tumoral pre-clinical activity and preliminary efficacy and safety profile in clinical testing. To improve potency further, we engineered a hybrid IgE-IgG1 antibody (IgEG), to combine the functions of both isotypes. Two IgEGs were generated with variable regions taken from trastuzumab (Tras IgEG) and from a novel anti-HER2 IgE (26 IgEG). Both IgEGs expressed well in mammalian cells and demonstrated IgE-like stability. IgEGs demonstrated both IgE and IgG1 functionality in vitro. A lack of type I hypersensitivity associated with IgEG incubation with human blood is suggestive of acceptable safety. In vivo, IgEGs exhibited distinct pharmacokinetic profiles and produced anti-tumoral efficacy comparable to IgE. These findings highlight the potential of IgEG as a new therapeutic modality in oncology.

Circulating immunoregulatory B cell and autoreactive antibody profiles predict lack of toxicity to anti-PD-1 checkpoint inhibitor treatment in advanced melanoma

BACKGROUND

The majority of patients with melanoma develop immune-related adverse events (irAEs), and over half do not respond to anti-PD-1 (Programmed cell death protein 1) checkpoint inhibitor (CPI) immunotherapy. Accurate predictive biomarkers for both response to therapy and development of irAEs are currently lacking in clinical practice. Here, we conduct deep immunophenotyping of circulating regulatory and class-switched B cell and antibody immune states in patients with advanced stage III/IV melanoma prior to and longitudinally during CPI.

METHODS

Mass cytometry, serum antibody isotyping and immuno-mass spectrometry proteome-wide screening evaluations to identify autoreactive antibodies were undertaken to profile circulating humoral immunity features in patients and healthy subjects and interrogate pretreatment B cell and antibody signatures that predict toxicity and response to anti-PD-1 therapy. In paired blood samples pretreatment and post-treatment, these humoral immune response profiles were monitored and correlated with the onset of toxicity.

RESULTS

We found increased circulating IL-10+ (Interleukin-10+) plasmablasts and double-negative (DN) B cell frequencies, higher PD-L1 (programmed death ligand 1), TGFβ (Transforming Growth Factorβ) and CD95 expression by B cells, alongside higher IgG4 and IgE serum levels in patients with stage III/IV melanoma. This suggests enhanced B regulatory and Th2 (Thelper2)-driven responses in advanced disease. Increased baseline frequency of DN2 B cells, plasmablasts, and serum IgE, IgA and antibody autoreactivity were observed in patients who did not develop irAE. During treatment, higher IL-10+class-switched memory B cell, plasmablast and IgG1, IgG3 and IgE, alongside reduced IgG2, IgG4, IgA and IgM levels, were observed. A reduction in autoantibodies targeting tubulins was observed during treatment. Increased frequency of class-switched memory B cells predicted improved survival, while reduced transitional and PD-L1+TGFβ+ naive B cell frequencies and higher IgG4 and IgE levels predicted lower survival, on anti-PD-1 therapy.

CONCLUSIONS

Distinct B cell and antibody reactivities in patients with advanced melanoma share features with extrafollicular B cell responses in autoimmune diseases, may be protective from irAE and help predict outcomes to anti-PD-1.

Tertiary Lymphoid Structures Are Associated with Enhanced Macrophage Activation and Immune Checkpoint Expression and Predict Outcome in Cervical Cancer

Cervical tumors are usually treated using surgery, chemotherapy, and radiotherapy and would benefit from immunotherapies. However, the immune microenvironment in cervical cancer remains poorly described. Tertiary lymphoid structures (TLS) were recently described as markers for better immunotherapy response and overall better prognosis in patients with cancer. We evaluated the cervical tumor immune microenvironment, specifically focusing on TLS, using combined high-throughput phenotyping, soluble factor concentration dosage in the tumor microenvironment, and spatial interaction analyses. We found that TLS presence was associated with a more inflammatory soluble microenvironment, with the presence of B cells as well as more activated macrophages and dendritic cells (DC). Furthermore, this myeloid cell activation was associated with the expression of immune checkpoints, such as PD-L1 and CD40, and the proximity of activated conventional type 2 DCs to CD8+ T cells, indicating better immune interactions and tumor control. Finally, we associated TLS presence, greater B-cell density, and activated DC density with improved progression-free survival, substantiating TLS presence as a potential prognostic marker. Our results provide evidence that TLS presence denotes cell activation and immunotherapy target expression.

Total IgE levels in patients with hematologic malignancies

Background

Immune system compartments have a crucial role in the progression or suppression of cancer. Hematologic malignancies are among the most common cancers, and there is conflicting research regarding the role of their relationship with allergies and IgE levels. This study aimed to compare total IgE levels in patients with hematologic malignancies to those in non-cancer controls.

Methods

In this cross-sectional study in 2023, sixty patients with hematological malignancies and 90 non-cancer patients attending Sari Imam Hospital were evaluated for total IgE levels along with demographic data. The convenience sampling method was used for the selection of both patients and controls. IgE levels were measured in both groups ELISA method. The analysis was performed using SPSS 20.

Results

The most common types of malignancy were ALL (23.3%) and multiple myeloma (23.3%). The median IgE level in patients (7.08, IQR:2.07-19.07) was significantly lower than the control group (42.41, IQR:11.99-145.57). The odds ratio for hematological malignancy associated with low total IgE was 6.79 (CI 95%: 2.90-15.92). After adjusting for age and sex, the adjusted odds ratio increased to 15.89 (CI 95%: 4.14-60.95).

Conclusion

Patients with hematological cancers have significantly lower IgE levels compared with individuals with no cancer.

Hyperinflammatory repolarisation of ovarian cancer patient macrophages by anti-tumour IgE antibody, MOv18, restricts an immunosuppressive macrophage:Treg cell interaction

Ovarian cancer is the most lethal gynaecological cancer and treatment options remain limited. In a recent first-in-class Phase I trial, the monoclonal IgE antibody MOv18, specific for the tumour-associated antigen Folate Receptor-α, was well-tolerated and preliminary anti-tumoural activity observed. Pre-clinical studies identified macrophages as mediators of tumour restriction and pro-inflammatory activation by IgE. However, the mechanisms of IgE-mediated modulation of macrophages and downstream tumour immunity in human cancer remain unclear. Here we study macrophages from patients with epithelial ovarian cancers naive to IgE therapy. High-dimensional flow cytometry and RNA-seq demonstrate immunosuppressive, FcεR-expressing macrophage phenotypes. Ex vivo co-cultures and RNA-seq interaction analyses reveal immunosuppressive associations between patient-derived macrophages and regulatory T (Treg) cells. MOv18 IgE-engaged patient-derived macrophages undergo pro-inflammatory repolarisation ex vivo and display induction of a hyperinflammatory, T cell-stimulatory subset. IgE reverses macrophage-promoted Treg cell induction to increase CD8+ T cell expansion, a signature associated with improved patient prognosis. On-treatment tumours from the MOv18 IgE Phase I trial show evidence of this IgE-driven immune signature, with increased CD68+ and CD3+ cell infiltration. We demonstrate that IgE induces hyperinflammatory repolarised states of patient-derived macrophages to inhibit Treg cell immunosuppression. These processes may collectively promote immune activation in ovarian cancer patients receiving IgE therapy.

A review on polysaccharide-based tumor targeted drug nanodelivery systems

The tumor-targeted drug delivery system (TTDNS) uses nanocarriers to transport chemotherapeutic agents to target tumor cells or tissues precisely. This innovative approach considerably increases the effective concentration of these drugs at the tumor site, thereby enhancing their therapeutic efficacy. Many chemotherapeutic agents face challenges, such as low bioavailability, high cytotoxicity, and inadequate drug resistance. To address these obstacles, TTDNS comprising natural polysaccharides have gained increasing popularity in the field of nanotechnology owing to their ability to improve safety, bioavailability, and biocompatibility while reducing toxicity. In addition, it enhances permeability and allows for controlled drug delivery and release. This review focuses on the sources of natural polysaccharides and their direct and indirect mechanisms of anti-tumor activity. We also explored the preparation of various polysaccharide-based nanocarriers, including nanoparticles, nanoemulsions, nanohydrogels, nanoliposomes, nanocapsules, nanomicelles, nanocrystals, and nanofibers. Furthermore, this review delves into the versatile applications of polysaccharide-based nanocarriers, elucidating their capabilities for in vivo targeting, controlled release, and responsiveness to endogenous and exogenous stimuli, such as pH, reactive oxygen species, glutathione, light, ultrasound, and magnetic fields. This sophisticated design substantially enhances the chemotherapeutic efficacy of the encapsulated drugs at tumor sites and provides a basis for preclinical and clinical research. However, the in vivo stability, drug loading, and permeability of these preparations into tumor tissues still need to be improved. Most of the currently developed biomarker-sensitive polysaccharide nanocarriers are still in the laboratory stage, more innovative delivery mechanisms and clinical studies are needed to develop commercial nanocarriers for medical use.

Fc-mediated immune stimulating, pro-inflammatory and antitumor effects of anti-HER2 IgE against HER2-expressing and trastuzumab-resistant tumors

BACKGROUND

Anti-human epidermal growth factor receptor 2 (HER2) IgG1-based antibody therapies significantly improve cancer prognosis, yet intrinsic or acquired resistance to fragment antigen-binding (Fab)-mediated direct effects commonly occurs. Most resistant tumors retain antigen expression and therefore remain potentially targetable with anti-HER2 therapies that promote immune-mediated responses. Tumor-antigen-specific IgE class antibodies can mediate powerful immune cell-mediated effects against different cancers and have been shown to activate IgE Fc receptor-expressing monocytes. We previously reported the engineering of a trastuzumab-equivalent anti-HER2 IgE antibody and showed early evidence of Fc-mediated cancer cell-targeting effects. In the present study, we evaluated the anti-tumoral functions of two anti-HER2 IgEs, trastuzumab and pertuzumab IgE.

METHODS

In vitro functionality of the two anti-HER2 antibodies was assessed by HER2 phosphorylation and ligand-independent viability assays, as well as basophil (RBL-SX38) degranulation, antibody-dependent cellular cytotoxicity/antibody-dependent cellular phagocytosis(ADCC/ADCP) assays and primary monocyte stimulation assays. The potential to trigger a hypersensitivity type I reaction was investigated using the basophil activation test (BAT). anti-tumoral efficacy was assessed in two humanized HER2+, trastuzumab-resistant models in vivo. Changes in the tumor microenvironment were assessed by flow cytometry or bulk RNA sequencing.

RESULTS

We demonstrate the anti-tumoral and immunostimulatory functions of two anti-HER2 IgEs derived from variable region sequences of the clinically available trastuzumab and pertuzumab IgG1 antibodies. IgE engagement of monocytes via the Fc region induced tumor cell cytotoxicity and a pro-inflammatory shift with upregulation of immune-stimulatory CD40, CD80 and CD86, and downregulation of scavenger CD163, cell surface molecules. This was accompanied by enhanced pro-inflammatory tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β cytokine production. The absence of basophil activation by anti-HER2 IgEs ex vivo in whole blood points to potentially safe administration in humans. In two trastuzumab-resistant HER2+ tumor xenograft models in immunodeficient mice reconstituted with human immune cells, the trastuzumab-equivalent anti-HER2 IgE restricted tumor growth. Treatment was associated with enriched classical (CD14+CD16-) monocyte and lower alternatively-activated (CD163+CD206+) macrophage infiltration, and higher densities of activated CD4+ (CD127loCD25hi) T cells and favorable effector T cell(Teff) to regulatory T cell (Treg) ratios in tumors.

CONCLUSION

Collectively, anti-HER2 IgE maintains Fab-mediated antitumor activity, induces Fc-mediated effects against HER2-expressing tumor cells, and stimulates remodeling of the immune microenvironment in tumors to promote pro-inflammatory cell phenotypes which could translate to improved outcomes for patients.

Type 2 immunity in allergic diseases

Significant advancements have been made in understanding the cellular and molecular mechanisms of type 2 immunity in allergic diseases such as asthma, allergic rhinitis, chronic rhinosinusitis, eosinophilic esophagitis (EoE), food and drug allergies, and atopic dermatitis (AD). Type 2 immunity has evolved to protect against parasitic diseases and toxins, plays a role in the expulsion of parasites and larvae from inner tissues to the lumen and outside the body, maintains microbe-rich skin and mucosal epithelial barriers and counterbalances the type 1 immune response and its destructive effects. During the development of a type 2 immune response, an innate immune response initiates starting from epithelial cells and innate lymphoid cells (ILCs), including dendritic cells and macrophages, and translates to adaptive T and B-cell immunity, particularly IgE antibody production. Eosinophils, mast cells and basophils have effects on effector functions. Cytokines from ILC2s and CD4+ helper type 2 (Th2) cells, CD8 + T cells, and NK-T cells, along with myeloid cells, including IL-4, IL-5, IL-9, and IL-13, initiate and sustain allergic inflammation via T cell cells, eosinophils, and ILC2s; promote IgE class switching; and open the epithelial barrier. Epithelial cell activation, alarmin release and barrier dysfunction are key in the development of not only allergic diseases but also many other systemic diseases. Recent biologics targeting the pathways and effector functions of IL4/IL13, IL-5, and IgE have shown promising results for almost all ages, although some patients with severe allergic diseases do not respond to these therapies, highlighting the unmet need for a more detailed and personalized approach.

An IgE antibody targeting HER2 identified by clonal selection restricts breast cancer growth via immune-stimulating activities

BACKGROUND

Tumor-targeting IgE antibodies have elicited potent tumor-restricting effects by recruiting immune effector mechanisms. However, a dedicated platform for the generation, selection and evaluation of novel IgEs based on target antigen recognition and functional profiles has not been reported.

METHODS

By establishing an IgE class antibody therapeutic design platform to allow selection of lead candidates, we generated a panel of IgEs recognising the human epidermal growth factor receptor 2 (HER2), overexpressed in 15-20% of breast cancers. From 1840 phage display-generated variable region sequences panned against HER2, we engineered 30 full length IgE antibodies. We selected three clones based on biophysical properties, reactivity to HER2 + cancer cells, epitope reactivity and Fc-mediated anti-tumor profiles in vitro. Clones with cross-reactivity to rat HER2 were selected to allow functional evaluations in a fully immunocompetent syngeneic HER2 + rat breast cancer model.

RESULTS

IgE antibodies induced degranulation and antibody-dependent cellular cytotoxicity against human and rat HER2-expressing tumor cells in vitro. IgE antibody 26 demonstrated anti-tumor activity in a syngeneic HER2 + rat model, and a human HER2 + breast cancer xenograft model in mice reconstituted with human immune cells. Treatment was associated with enhanced immune cell infiltration and pro-inflammatory immune signatures, and downregulated cancer progression signaling pathways, in the tumor microenvironment.

CONCLUSIONS

This study pioneers the design and generation of anti-HER2 IgE lead antibody candidates with immune-stimulating and tumor-restricting effects. The present work may pave the way for antibody engineering therapeutic opportunities for challenging-to-treat HER2-expressing cancers.

A reappraisal of IL-9 in inflammation and cancer

While much is known about the functional effects of type 2 cytokines interleukin (IL)-4, IL-5 and IL-13 in homeostasis and disease, we still poorly understand the functions of IL-9. Chronic inflammation seen in allergic diseases, autoimmunity and cancer is however frequently accompanied by overproduction of this elusive type 2 cytokine. Initially identified as a T cell and mast cell growth factor, and later as the hallmark cytokine defining TH9 cells, we now know that IL-9 is produced by multiple innate and adaptive immune cells. Recent evidence suggests that IL-9 controls discrete aspects of the allergic cascade, cellular responses of immune and stromal cells, cancer progression, tolerance and immune escape. Despite functioning as a pleiotropic cytokine in mucosal environments, like the lungs, the direct and indirect cellular targets of IL-9 are still not well characterized. Here, we discuss IL-9's cellular senders and receivers, focusing on asthma and cancer. Moreover, we review current research directions and the outlook of targeted therapy centered around the biology of IL-9.

Chondroitin sulfate proteoglycan 4 increases invasion of recessive dystrophic epidermolysis bullosa-associated cutaneous squamous cell carcinoma by modifying transforming growth factor-β signalling

BACKGROUND

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare genetic skin-blistering disorder that often progresses to metastatic cutaneous squamous cell carcinoma (cSCC) at chronic wound sites. Chondroitin sulfate proteoglycan 4 (CSPG4) is a cell-surface proteoglycan that is an oncoantigen in multiple malignancies, where it modulates oncogenic signalling, drives epithelial-to-mesenchymal transition (EMT) and enables cell motility.

OBJECTIVES

To evaluate CSPG4 expression and function in RDEB cSCC.

METHODS

RDEB cSCC cell lines were used to assess CSPG4-dependent changes in invasive potential, transforming growth factor (TGF)-β1-stimulated signal activation and clinically relevant cytopathology metrics in an in vitro full-thickness tumour model. CSPG4 expression in RDEB cSCC and non-RDEB cSCC tumours was analysed via immunohistochemistry and single-cell RNA sequencing (scRNA-Seq), respectively.

RESULTS

Inhibiting CSPG4 expression reduced invasive potential in multiple RDEB cSCC cell lines and altered membrane-proximal TGF-β signal activation via changes in SMAD3 phosphorylation. CSPG4 expression was uniformly localized to basal layer keratinocytes in fibrotic RDEB skin and tumour cells at the tumour-stroma interface at the invasive front in RDEB cSCC tumours in vivo. Analysis of published scRNA-Seq data revealed that CSPG4 expression was correlated with an enhanced EMT transcriptomic signature in cells at the tumour-stroma interface of non-RDEB cSCC tumours. Cytopathological metrics, for example nucleus : cell area ratio, were influenced by CSPG4 expression in in vitro tumour models.

CONCLUSIONS

We determined that CSPG4 expression in RDEB cSCC cell lines enhanced the invasive potential of tumours. Mechanistically, CSPG4 was found to enhance membrane-proximal TGF-β-stimulated signalling via SMAD3, which is a key mediator of EMT in RDEB cSCC. The implication of these studies is that CSPG4 may represent a therapeutic target that can be leveraged for the clinical management of patients with RDEB cSCC.

Expression of mast cell tryptase and immunoglobulin E is increased in cutaneous photodamage: implications for carcinogenesis

Purpose: Mast cells, their serine proteinase tryptase, and immunoglobulin E (IgE) can be involved in cutaneous carcinogenesis.Materials and methods: To study the association of tryptase+ and IgE+ cells with photodamage and skin cancers 385 adult patients (201 males, 184 females, 75 with immunosuppression) at risk of any type of skin cancer were examined. Skin biopsies were taken from the sun-protected medial arm and from the photodamaged dorsal forearm skin followed by immunohistochemical staining for tryptase and IgE.Results: The results show that tryptase+ and IgE+ cells are significantly higher in number in the photodamaged than sun-protected skin, both in immunocompetent and -compromised subjects, and there is a strong correlation between tryptase+ and IgE+ cells. The numbers of forearm tryptase+ and especially IgE+ cells associated significantly with the forearm photodamage severity. In the logistic regression analysis, the forearm to upper arm ratio of IgE+ cells produced a univariate odds ratio of 1.521 (p = .010) and a multivariate one of 3.875 (p = .047) for the history of squamous cell carcinoma. The serum level of total IgE correlated significantly to the IgE to tryptase ratio in both skin sites.Conclusions: Therefore, IgE+ mast cells participate in photodamage and carcinogenesis, though it is unclear whether they are tumor-protective or -causative.

Systematic mutational analysis reveals an essential role of N275 in IgE stability

Therapeutic antibodies have predominantly been IgG-based. However, the ongoing clinical trial of MOv18 IgE has highlighted the potential of using IgE antibodies in cancer therapy. While extensive studies targeting IgG glycosylation resulted in a rational basis for the development of enhanced biotherapeutics, IgE glycosylation remains an area with limited analyses. Previous studies on the role of IgE glycosylation present conflicting data with one study emphasizing the importance of N275 and T277 residues for FcεRI binding whereas another asserts the nonsignificance of IgE glycosylation in receptor interaction. While existing literature underscores the significance of glycans at the N275 position for binding to FcεR1 receptor and initiation of anaphylaxis, the role of other IgE glycosylation sites in folding or receptor binding remains elusive. This study systematically investigates the functional significance of N-linked glycosylation sites in the heavy chain of IgE which validates the pivotal role of N275 residue in IgE secretion and stability. Replacement of this asparagine to non-amine group moieties does not affect IgE function in vitro, yet substitution with aspartic acid compromises antibody yield. The deglycosylated IgE variant exhibits superior efficacy, challenging the conventional importance of glycosylation for effector function. In summary, our study unveils an intricate relationship between N-glycosylation sites and the structural-functional dynamics of IgE antibodies. Furthermore, it offers novel insights into the IgE scaffold, paving the way for the development of more effective and stable IgE-based therapeutics.

Secretory Nogo-B regulates Th2 differentiation in the lung cancer microenvironment

Nogo-B, a ubiquitously expressed member of the reticulon family, plays an important role in maintaining endoplasmic reticulum (ER) structure, regulating protein folding, and calcium homeostasis. In this study, we demonstrate that Nogo-B expression and secretion are upregulated in lung cancer and correlate to overall survival. Nogo-B is secreted by various cells, particularly lung cancer cells. ER stress and phosphorylation at serine 107 can induce Nogo-B secretion. Secretory Nogo-B suppresses the differentiation of Th2 cells and the release of type 2 cytokines, thus influencing the anti-tumor effects of Th2-related immune cells, including IgE+B cell class switching and eosinophil activation.

Pathophysiology of Congenital High Production of IgE and Its Consequences: A Narrative Review Uncovering a Neglected Setting of Disorders

Elevated serum IgE levels serve as a critical marker for uncovering hidden immunological disorders, particularly inborn errors of immunity (IEIs), which are often misdiagnosed as common allergic conditions. IgE, while typically associated with allergic diseases, plays a significant role in immune defense, especially against parasitic infections. However, extremely high levels of IgE can indicate more severe conditions, such as Hyper-IgE syndromes (HIES) and disorders with similar features, including Omenn syndrome, Wiskott-Aldrich syndrome, and IPEX syndrome. Novel insights into the genetic mutations responsible for these conditions highlight their impact on immune regulation and the resulting clinical features, including recurrent infections, eczema, and elevated IgE. This narrative review uniquely integrates recent advances in the genetic understanding of IEIs and discusses how these findings impact both diagnosis and treatment. Additionally, emerging therapeutic strategies, such as hematopoietic stem cell transplantation (HSCT) and gene therapies, are explored, underscoring the potential for personalized treatment approaches. Emphasizing the need for precise diagnosis and tailored interventions aims to enhance patient outcomes and improve the quality of care for those with elevated IgE levels and associated immunological disorders.

IgE glycosylation and impact on structure and function: A systematic review

The impact of human IgE glycosylation on structure, function and disease mechanisms is not fully elucidated, and heterogeneity in different studies renders drawing conclusions challenging. Previous reviews discussed IgE glycosylation focusing on specific topics such as health versus disease, FcεR binding or impact on function. We present the first systematic review of human IgE glycosylation conducted utilizing the PRISMA guidelines. We sought to define the current consensus concerning the roles of glycosylation on structure, biology and disease. Despite diverse analytical methodologies, source, expression systems and the sparsity of data on IgE antibodies from non-allergic individuals, collectively evidence suggests differential glycosylation profiles, particularly in allergic diseases compared with healthy states, and indicates functional impact, and contributions to IgE-mediated hypersensitivities and atopic diseases. Beyond allergic diseases, dysregulated terminal glycan structures, including sialic acid, may regulate IgE metabolism. Glycan sites such as N394 may contribute to stabilizing IgE structure, with alterations in these glycans likely influencing both structure and IgE-FcεR interactions. This systematic review therefore highlights critical IgE glycosylation attributes in health and disease that may be exploitable for therapeutic intervention, and the need for novel analytics to explore pertinent research avenues.

Chondroitin Sulfate Proteoglycan 4 (CSPG4) as an Emerging Target for Immunotherapy to Treat Melanoma

Immunotherapies, including checkpoint inhibitor antibodies, have precipitated significant improvements in clinical outcomes for melanoma. However, approximately half of patients do not benefit from approved treatments. Additionally, apart from Tebentafusp, which is approved for the treatment of uveal melanoma, there is a lack of immunotherapies directly focused on melanoma cells. This is partly due to few available targets, especially those expressed on the cancer cell surface. Chondroitin sulfate proteoglycan 4 (CSPG4) is a cell surface molecule overexpressed in human melanoma, with restricted distribution and low expression in non-malignant tissues and involved in several cancer-promoting and dissemination pathways. Here, we summarize the current understanding of the expression and functional significance of CSPG4 in health and melanoma, and we outline immunotherapeutic strategies. These include monoclonal antibodies, antibody-drug conjugates (ADCs), chimeric-antigen receptor (CAR) T cells, and other strategies such as anti-idiotypic and mimotope vaccines to raise immune responses against CSPG4-expressing melanomas. Several showed promising functions in preclinical models of melanoma, yet few have reached clinical testing, and none are approved for therapeutic use. Obstacles preventing that progress include limited knowledge of CSPG4 function in human cancer and a lack of in vivo models that adequately represent patient immune responses and human melanoma biology. Despite several challenges, immunotherapy directed to CSPG4-expressing melanoma harbors significant potential to transform the treatment landscape.

Tumor associated macrophages as key contributors and targets in current and future therapies for melanoma

INTRODUCTION

Despite the success of immunotherapies for melanoma in recent years, there remains a significant proportion of patients who do not yet derive benefit from available treatments. Immunotherapies currently licensed for clinical use target the adaptive immune system, focussing on Tcell interactions and functions. However, the most prevalent immune cells within the tumor microenvironment (TME) of melanoma are macrophages, a diverse immune cell subset displaying high plasticity, to which no current therapies are yet directly targeted. Macrophages have been shown not only to activate the adaptive immune response, and enhance cancer cell killing, but, when influenced by factors within the TME of melanoma, these cells also promote melanoma tumorigenesis and metastasis.

AREAS COVERED

We present a review of the most up-to-date literatureavailable on PubMed, focussing on studies from within the last 10 years. We also include data from ongoing and recent clinical trials targeting macrophages in melanoma listed on clinicaltrials.gov.

EXPERT OPINION

Understanding the multifaceted role of macrophages in melanoma, including their interactions with immune and cancer cells, the influence of current therapies on macrophage phenotype and functions and how macrophages could be targeted with novel treatment approaches, are all critical for improving outcomes for patients with melanoma.

A Comparison of Natural and Therapeutic Anti-IgE Antibodies

Immunoglobulin E (IgE) plays a critical role for the immune system, fighting against parasites, toxins, and cancer. However, when it reacts to allergens without proper regulation, it can cause allergic reactions, including anaphylaxis, through a process initiated by effector cells such as basophils and mast cells. These cells display IgE on their surface, bound to the high-affinity IgE receptor FcεRI. A cross-linking antigen then triggers degranulation and the release of inflammatory mediators from the cells. Therapeutic monoclonal anti-IgE antibodies such as omalizumab, disrupt this process and are used to manage IgE-related conditions such as severe allergic asthma and chronic spontaneous urticaria. Interestingly, naturally occurring anti-IgE autoantibodies circulate at surprisingly high levels in healthy humans and mice and may thus be instrumental in regulating IgE activity. Although many open questions remain, recent studies have shed new light on their role as IgE regulators and their mechanism of action. Here, we summarize the latest insights on natural anti-IgE autoantibodies, and we compare their functional features to therapeutic monoclonal anti-IgE autoantibodies.

JAK1/JAK2 degraders based on PROTAC for topical treatment of atopic dermatitis

Atopic dermatitis (AD) is a prevalent chronic inflammatory skin disease. The Janus kinase (JAK) has been identified as a target in AD, as it regulates specific inflammatory genes and adaptive immune responses. However, the efficacy of topically applied JAK inhibitors in AD is limited due to the unique structure of skin. We synthesized JAK1/JAK2 degraders (JAPT) based on protein degradation targeting chimeras (PROTACs) and prepared them into topical preparations. JAPT exploited the E3 ligase to mediate ubiquitination and degradation of JAK1/JAK2, offering a promising AD therapeutic approach with low frequency and dosage. In vitro investigations demonstrated that JAPT effectively inhibited the release of pro-inflammatory cytokines and reduced inflammation by promoting the degradation of JAK. In vivo studies further confirmed the efficacy of JAPT in degrading JAK1/JAK2, leading to a significant suppression of type I, II, and III adaptive immunity. Additionally, JAPT demonstrated a remarkable reduction in AD severity, as evidenced by improved skin lesion clearance and AD severity scores (SCORAD). Our study revealed the therapeutic potential of JAPT, surpassing conventional JAK inhibitors in the treatment of AD, which suggested that JAPT could be a promising topically applied anti-AD drug targeting the JAK-STAT signaling pathway.

Exogenous recombinant N-acetylgalactosamine-4-sulfatase (Arylsulfatase B; ARSB) inhibits progression of B16F10 cutaneous melanomas and modulates cell signaling

In the syngeneic, subcutaneous B16F10 mouse model of malignant melanoma, treatment with exogenous ARSB markedly reduced tumor size and extended survival. In vivo experiments showed that local treatment with exogenous N-acetylgalactosamine-4-sulfatase (Arylsulfatase B; ARSB) led to reduced tumor growth over time (p < 0.0001) and improved the probability of survival up to 21 days (p = 0.0391). Tumor tissue from the treated mice had lower chondroitin 4-sulfate (C4S) content and lower sulfotransferase activity. The free galectin-3 declined, and the SHP2 activity increased, due to altered binding with chondroitin 4-sulfate. These changes induced effects on transcription, which were mediated by Sp1, phospho-ERK1/2, and phospho-p38 MAPK. Reduced mRNA expression of chondroitin sulfate proteoglycan 4 (CSPG4), carbohydrate sulfotransferase 15 (N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase), and matrix metalloproteinases 2 and 9 resulted. Experiments in the human melanoma cell line A375 demonstrated similar responses to exogenous ARSB as in the tumors, and inverse effects followed ARSB siRNA. ARSB, which removes the 4-sulfate group at the non-reducing end of C4S, acts as a tumor suppressor, and treatment with exogenous ARSB impacts on vital cell signaling and reduces the expression of critical genes associated with melanoma progression.

Chondroitin sulfate proteoglycan 4: An attractive target for antibody-based immunotherapy

Multifunctional molecules involved in tumor progression and metastasis have been identified as valuable targets for immunotherapy. Among these, chondroitin sulfate proteoglycan 4 (CSPG4), a significant tumor cell membrane-bound proteoglycan, has emerged as a promising target, especially in light of advances in chimeric antigen receptor (CAR) T-cell therapy. The profound bioactivity of CSPG4 and its role in pivotal processes such as tumor proliferation, migration, and neoangiogenesis underline its therapeutic potential. We reviewed the molecular intricacies of CSPG4, its functional attributes within tumor cells, and the latest clinical-translational advances targeting it. Strategies such as blocking monoclonal antibodies, conjugate therapies, bispecific antibodies, small-molecule inhibitors, CAR T-cell therapies, trispecific killer engagers, and ribonucleic acid vaccines against CSPG4 were assessed. CSPG4 overexpression in diverse tumors and its correlation with adverse prognostic outcomes emphasize its significance in cancer biology. These findings suggest that targeting CSPG4 offers a promising avenue for future cancer therapy, with potential synergistic effects when combined with existing treatments.

Fcγ receptors and immunomodulatory antibodies in cancer

The discovery of both cytotoxic T lymphocyte-associated antigen 4 (CTLA4) and programmed cell death protein 1 (PD1) as negative regulators of antitumour immunity led to the development of numerous immunomodulatory antibodies as cancer treatments. Preclinical studies have demonstrated that the efficacy of immunoglobulin G (IgG)-based therapies depends not only on their ability to block or engage their targets but also on the antibody's constant region (Fc) and its interactions with Fcγ receptors (FcγRs). Fc-FcγR interactions are essential for the activity of tumour-targeting antibodies, such as rituximab, trastuzumab and cetuximab, where the killing of tumour cells occurs at least in part due to these mechanisms. However, our understanding of these interactions in the context of immunomodulatory antibodies designed to boost antitumour immunity remains less explored. In this Review, we discuss our current understanding of the contribution of FcγRs to the in vivo activity of immunomodulatory antibodies and the challenges of translating results from preclinical models into the clinic. In addition, we review the impact of genetic variability of human FcγRs on the activity of therapeutic antibodies and how antibody engineering is being utilized to develop the next generation of cancer immunotherapies.

Therapeutic Monoclonal Antibodies against Cancer: Present and Future

A series of monoclonal antibodies with therapeutic potential against cancer have been generated and developed. Ninety-one are currently used in the clinics, either alone or in combination with chemotherapeutic agents or other antibodies, including immune checkpoint antibodies. These advances helped to coin the term personalized medicine or precision medicine. However, it seems evident that in addition to the current work on the analysis of mechanisms to overcome drug resistance, the use of different classes of antibodies (IgA, IgE, or IgM) instead of IgG, the engineering of the Ig molecules to increase their half-life, the acquisition of additional effector functions, or the advantages associated with the use of agonistic antibodies, to allow a broad prospective usage of precision medicine successfully, a strategy change is required. Here, we discuss our view on how these strategic changes should be implemented and consider their pros and cons using therapeutic antibodies against cancer as a model. The same strategy can be applied to therapeutic antibodies against other diseases, such as infectious or autoimmune diseases.