Glycosylation profiles determine extravasation and disease-targeting properties of armed antibodies

Targeted Cytokine Delivery for Cancer Treatment: Engineering and Biological Effects

Anti-tumor properties of several cytokines have already been investigated in multiple experiments and clinical trials. However, those studies evidenced substantial toxicities, even at low cytokine doses, and the lack of tumor specificity. These factors significantly limit clinical applications. Due to their high specificity and affinity, tumor-specific monoclonal antibodies or their antigen-binding fragments are capable of delivering fused cytokines to tumors and, therefore, of decreasing the number and severity of side effects, as well as of enhancing the therapeutic index. The present review surveys the actual antibody-cytokine fusion protein (immunocytokine) formats, their targets, mechanisms of action, and anti-tumor and other biological effects. Special attention is paid to the formats designed to prevent the off-target cytokine-receptor interactions, potentially inducing side effects. Here, we describe preclinical and clinical data and the efficacy of the antibody-mediated cytokine delivery approach, either as a single therapy or in combination with other agents.

Integrated Multi-Omics Data Analysis Reveals Associations Between Glycosylation and Stemness in Hepatocellular Carcinoma

Background

Glycosylation plays an essential role in driving the progression and treatment resistance of hepatocellular carcinoma (HCC). However, its function in regulating the acquisition and maintenance of the cancer stemness-like phenotype in HCC remains largely unknown. There is also very little known about how CAD and other potential glycosylation regulators may influence stemness. This study explores the relationship between glycosylation and stemness in HCC.

Methods

Gene set variance analysis (GSVA) was used to assess the TCGA pan-cancer enrichment in glycosylation-related pathways. Univariate, LASSO, and multivariate COX regression were then used to identify prognostic genes in the TCGA-LIHC and construct a prognostic signature. HCC patients were classified into high- and low-risk subgroups based on the signature. The relationship between gene expression profiles and stemness was confirmed using bulk and single-cell RNA-sequencing data. The role of CAD and other genes in regulating the stemness of HCC was also validated by RT-qPCR, CCK-8, and colony formation assay. Copy number variation (CNV), immune infiltration, and clinical features were further analyzed in different subgroups and subsequent gene expression profiles. Sensitive drugs were also screened.

Results

In the pan-cancer analysis, HCC was shown to have specific glycosylation alterations. Five genes, CAD, SLC51B, LGALS3, B3GAT3, and MT3, identified from 572 glycosylation-related genes, were used to construct a gene signature and predict HCC patient survival in the TCGA cohort. The results demonstrated a significant positive correlation between patients in the high-risk group and both elevated gene expression and HCC dedifferentiation status. A significant reduction in the stemness-related markers, CD24, CD44, CD20, FOXM1, and EpCAM, was found after the knockdown of CAD and other genes in HepG2 and Huh7 cells. Frequent mutations increased CNVs, immune-suppressive responses, and poor prognosis were also associated with the high-risk profile. The ICGC-LIRI-JP cohort confirmed a similar relationship between glycosylation-related subtypes and stemness. Finally, 84 sensitive drugs were screened for abnormal glycosylation of HCC, and carfilzomib was most highly correlated with CAD.

Conclusions

Glycosylation-related molecular subtypes are associated with HCC stemness and disease prognosis. These results provide new directions for further research on the relationship between glycosylation and stemness phenotypes.

ANALYSIS OF CARBOHYDRATES AND GLYCOCONJUGATES BY MATRIX-ASSISTED LASER DESORPTION/IONIZATION MASS SPECTROMETRY: AN UPDATE FOR 2015-2016

This review is the ninth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2016. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented over 30 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show no sign of deminishing. © 2020 Wiley Periodicals, Inc.

Antibody-based delivery of interleukin-9 to neovascular structures: Therapeutic evaluation in cancer and arthritis

Interleukin-9 is a cytokine with multiple functions, including the ability to activate group 2 innate lymphoid cells, which has been postulated to be therapeutically active in mouse models of arthritis. Similarly, interleukin-9 has been suggested to play an important role in tumor immunity. Here, we describe the cloning, expression, and characterization of three fusion proteins based on murine interleukin-9 and the F8 antibody, specific to the alternatively spliced EDA domain of fibronectin. EDA is strongly expressed in cancer and in various arthritic conditions, while being undetectable in the majority of healthy organs. Interleukin-9-based fusion proteins with an irrelevant antibody specific to hen egg lysozyme served as negative control in our study. The fusion proteins were characterized by quantitative biodistribution analysis in tumor-bearing mice using radioiodinated protein preparations. The highest tumor uptake and best tumor:organ ratios were observed for a format, in which the interleukin-9 moiety was flanked by two units of the F8 antibody in single-chain Fv format. Biological activity of interleukin-9 was retained when the payload was fused to antibodies. However, the targeted delivery of interleukin-9 to the disease site resulted in a modest anti-tumor activity in three different murine models of cancer (K1735M2, CT26, and F9), while no therapeutic benefit was observed in a collagen induced model of arthritis. Collectively, these results confirm the possibility to deliver interleukin-9 to the site of disease but cast doubts about the alleged therapeutic activity of this cytokine in cancer and arthritis, which has been postulated in previous publications.

Antibody-mediated delivery of LIGHT to the tumor boosts natural killer cells and delays tumor progression

LIGHT is a member of the tumor necrosis factor superfamily, which has been claimed to mediate anti-tumor activity on the basis of cancer cures observed in immunocompetent mice bearing transgenic LIGHT-expressing tumors. The preclinical development of a LIGHT-based therapeutic has been hindered by the lack of functional stability exhibited by this protein. Here, we describe the cloning, expression, and characterization of five antibody-LIGHT fusion proteins, directed against the alternatively spliced extra domain A of fibronectin, a conserved tumor-associated antigen. Among the five tested formats, only the sequential fusion of the F8 antibody in single-chain diabody format, followed by the LIGHT homotrimer expressed as a single polypeptide, yielded a protein (termed "F8-LIGHT") that was not prone to aggregation. A quantitative biodistribution analysis in tumor-bearing mice, using radio-iodinated protein preparations, confirmed that F8-LIGHT was able to preferentially accumulate at the tumor site, with a tumor-to-blood ratio of ca. five to one 24 hours after intravenous administration. Tumor therapy experiments, performed in two murine tumor models (CT26 and WEHI-164), featuring different levels of lymphocyte infiltration into the neoplastic mass, revealed that F8-LIGHT could significantly reduce tumor-cell growth and was more potent than a similar fusion protein (KSF-LIGHT), directed against hen egg lysozyme and serving as negative control of irrelevant specificity in the mouse. At a mechanistic level, the activity of F8-LIGHT was mainly due to an intratumoral expansion of natural killer cells, whereas there was no evidence of expansion of CD8 + T cells, neither in the tumor, nor in draining lymph nodes. Abbreviations: CTLA-4: Cytotoxic T-lymphocytes-associated protein 4; EGFR: Epidermal growth factor receptor; HVEM: Herpesvirus entry mediator; IFNγ: Interferon-gamma; LIGHT: Lymphotoxin, exhibits inducible expression and competes with HSV glycoprotein D for binding to herpesvirus entry mediator, a receptor expressed on T lymphocytes; LTβR: Lymphotoxin beta receptor; NF-κB: Nuclear factor "kappa-light-chain-enhancer" of activated B cells; NK: Natural killer cells; PD-1: Programmed cell death protein 1; PD-L1: Programmed death-ligand 1; TNF: Tumor necrosis factor.

Targeting an engineered cytokine with interleukin-2 and interleukin-15 activity to the neovasculature of solid tumors

There is a growing interest in the antibody-based delivery of cytokines to the tumor environment as a means to boost the anti-cancer activity of tumor-resident T cells and NK cells. Here, we describe the expression and characterization of fusion proteins, featuring the L19 antibody (specific to the alternatively-spliced EDB domain of fibronectin) and an engineered cytokine with interleukin-2 and interleukin-15 properties. The cytokine moiety was fused either at the N-terminal or at the C-terminal extremity and both fusion proteins showed a selective tumor accumulation in a quantitative biodistribution experiment. The N-terminal fusion inhibited tumor growth in immunocompetent mice bearing F9 carcinomas or WEHI-164 sarcomas when used as single agent. The anticancer activity was compared to the one of the same cytokine payload used as recombinant protein or fused to an anti-hen egg lysozyme antibody, serving as negative control of irrelevant specificity in the mouse. These results indicate that the antibody-based delivery of engineered cytokines to the tumor neovasculature may mediate a potent anticancer activity.

Antibody-Cytokine Fusions: Versatile Products for the Modulation of Anticancer Immunity

The remarkable clinical success of immune-checkpoint inhibitors for the treatment of a growing number of cancer types has sparked interest in the discovery of novel forms of immunotherapy, which may be used alone or in combination. In this context, cytokine-based therapeutics are well poised to play a role in modern cancer therapy. This article focuses on antibody-cytokine fusion proteins (also called "immunocytokines") as one class of biopharmaceuticals that can substantially improve the therapeutic index and, thus, the applicability of cytokine products. In many preclinical settings, antibodies can be used to preferentially deliver many (but not all) types of cytokines to primary and metastatic tumor lesions. The antibody-based delivery of certain proinflammatory payloads (such as IL2, IL12, and TNF) to the tumor microenvironment can lead to a dramatic potentiation of their anticancer activity. However, although some fusion proteins have advanced to late-stage clinical trials, much work remains to be done in order to fully characterize the mechanism of action and the pharmaceutical potential of immunocytokines in the clinical setting. Various factors contribute to in vivo performance, including the target antigen, the antibody properties, the nature of the payload, the format of the fusion protein, the dose, and schedule, as well as their use in combination with other therapeutic modalities. Protein engineering opportunities and insights in cancer immunology are contributing to the development of next-generation immunocytokine products and of novel therapeutic concepts, with the goal to increase antitumor activity and reduce systemic toxicity (a common problem for cytokine-based biopharmaceuticals).

The biodistribution of therapeutic proteins: Mechanism, implications for pharmacokinetics, and methods of evaluation

Therapeutic proteins (TPs) are a diverse drug class that include monoclonal antibodies (mAbs), recombinantly expressed enzymes, hormones and growth factors, cytokines (e.g. chemokines, interleukins, interferons), as well as a wide range of engineered fusion scaffolds containing IgG1 Fc domain for half-life extension. As the pharmaceutical industry advances more potent and selective protein-based medicines through discovery and into the clinical stages of development, it has become widely appreciated that a comprehensive understanding of the mechanisms of TP biodistribution can aid this endeavor. This review aims to highlight the literature that has advanced our understanding of the determinants of TP biodistribution. A particular emphasis is placed on the multi-faceted role of the neonatal Fc receptor (FcRn) in mAb and Fc-fusion protein disposition. In addition, characterization of the TP-target interaction at the cell-level is discussed as an essential strategy to establish pharmacokinetic-pharmacodynamic (PK/PD) relationships that may lead to more informed human dose projections during clinical development. Methods for incorporation of tissue and cell-level parameters defining these characteristics into higher-order mechanistic and semi-mechanistic PK models will also be presented.

Safety Profile of a Virus-Like Particle-Based Vaccine Targeting Self-Protein Interleukin-5 in Horses

Background: Insect bite hypersensitivity (IBH) is an eosinophilic allergic dermatitis of horses caused by type I/IVb reactions against mainly Culicoides bites. The vaccination of IBH-affected horses with equine IL-5 coupled to the Cucumber mosaic virus-like particle (eIL-5-CuMV_TT) induces IL-5-specific auto-antibodies, resulting in a significant reduction in eosinophil levels in blood and clinical signs. Objective: the preclinical and clinical safety of the eIL-5-CuMV_TT vaccine. Methods: The B cell responses were assessed by longitudinal measurement of IL-5- and CuMV_TT-specific IgG in the serum and plasma of vaccinated and unvaccinated horses. Further, peripheral blood mononuclear cells (PBMCs) from the same horses were re-stimulated in vitro for the proliferation and IFN-γ production of specific T cells. In addition, we evaluated longitudinal kidney and liver parameters and the general blood status. An endogenous protein challenge was performed in murine IL-5-vaccinated mice. Results: The vaccine was well tolerated as assessed by serum and cellular biomarkers and also induced reversible and neutralizing antibody titers in horses and mice. Endogenous IL-5 stimulation was unable to re-induce anti-IL-5 production. The CD4⁺ T cells of vaccinated horses produced significantly more IFN-γ and showed a stronger proliferation following stimulation with CuMV_TT as compared to the unvaccinated controls. Re-stimulation using E. coli-derived proteins induced low levels of IFNγ⁺CD4⁺ cells in vaccinated horses; however, no IFN-γ and proliferation were induced following the HEK-eIL-5 re-stimulation. Conclusions: Vaccination using eIL-5-CuMV_TT induces a strong B-cell as well as CuMV_TT-specific T cell response without the induction of IL-5-specific T cell responses. Hence, B-cell unresponsiveness against self-IL-5 can be bypassed by inducing CuMV_TT carrier-specific T cells, making the vaccine a safe therapeutic option for IBH-affected horses.

Targeted enhancement of the therapeutic window of L19-TNF by transient and selective inhibition of RIPK1-signaling cascade

Introduction

Cytokine-based products are gaining importance for cancer immunotherapy. L19-TNF is a clinical-stage antibody-cytokine fusion protein that selectively accumulates to tumors and displays potent anticancer activity in preclinical models. Here, we describe an innovative approach to transiently inhibit off-target toxicity of L19-TNF, while maintaining antitumor activity.

Methods

GSK’963, a potent small molecule inhibitor of RIPK1, was tested in tumor-bearing mice for its ability to reduce acute toxicity associated with TNF signaling. The biological effects of L19-TNF on tumor cells, lymphocytes and tumor vessels were investigated with the aim to enable the administration of TNF doses, which would otherwise be lethal.

Results

Transient inhibition of RIPK1 allowed to increase the maximal tolerated dose of L19-TNF. The protective effect of GSK’963 did not affect the selective localization of the immunocytokine to tumors as evidenced by quantitative biodistribution analysis and allowed to reach high local TNF concentrations around tumor blood vessels, causing diffused vascular shutdown and hemorrhagic necrosis within the neoplastic mass.

Conclusions

The selective inhibition of RIPK1 with small molecule inhibitors can be used as a pharmaceutical tool to transiently mask TNF activity and improve the therapeutic window of TNF-based biopharmaceuticals. Similar approaches may be applicable to other pro-inflammatory cytokines.

Glycans in drug discovery

Glycans are key players in many biological processes. They are essential for protein folding and stability and act as recognition elements in cell-cell and cell-matrix interactions. Thus, being at the heart of medically relevant biological processes, glycans have come onto the scene and are considered hot spots for biomedical intervention. The progress in biophysical techniques allowing access to an increasing molecular and structural understanding of these processes has led to the development of effective therapeutics. Indeed, strategies aimed at designing glycomimetics able to block specific lectin-carbohydrate interactions, carbohydrate-based vaccines mimicking self- and non-self-antigens as well as the exploitation of the therapeutic potential of glycosylated antibodies are being pursued. In this mini-review the most prominent contributions concerning recurrent diseases are highlighted, including bacterial and viral infections, cancer or immune-related pathologies, which certainly show the great promise of carbohydrates in drug discovery.

Novel NMR Avenues to Explore the Conformation and Interactions of Glycans

This perspective article is focused on the presentation of the latest advances in NMR methods and applications that are behind the exciting achievements in the understanding of glycan receptors in molecular recognition events. Different NMR-based methodologies are discussed along with their applications to scrutinize the conformation and dynamics of glycans as well as their interactions with protein receptors.

Antibody-cytokine fusion proteins: A novel class of biopharmaceuticals for the therapy of cancer and of chronic inflammation

Antibody-cytokine fusion proteins represent a novel class of biopharmaceuticals, with the potential to increase the therapeutic index of cytokine 'payloads' and to promote leukocyte infiltration at the site of disease. In this review, we present a survey of immunocytokines that have been used in preclinical models of cancer and in clinical trials. In particular, we highlight how antibody format, choice of target antigen and cytokine engineering, as well as combination strategies, may have a profound impact on therapeutic performance. Moreover, by using anti-inflammatory cytokines, antibody fusion strategies can conveniently be employed for the treatment of auto-immune and chronic inflammatory conditions.

Antibody-cytokine fusion proteins: Biopharmaceuticals with immunomodulatory properties for cancer therapy

Cytokines have long been used for therapeutic applications in cancer patients. Substantial side effects and unfavorable pharmacokinetics limit their application and may prevent dose escalation to therapeutically active regimens. Antibody-cytokine fusion proteins (often referred to as immunocytokines) may help localize immunomodulatory cytokine payloads to the tumor, thereby activating anticancer immune responses. A variety of formats (e.g., intact IgGs or antibody fragments), molecular targets (e.g., extracellular matrix components and cell membrane antigens) and cytokine payloads have been considered for the development of this novel class of biopharmaceuticals. This review presents the basic concepts on the design and engineering of immunocytokines, reviews their potential limitations, points out emerging opportunities and summarizes key features of preclinical and clinical-stage products.

The Mechanistic Impact of N-Glycosylation on Stability, Pharmacokinetics, and Immunogenicity of Therapeutic Proteins

N-glycosylation is one of major post-translational modifications in nature, and it is essential for protein structure and function. As hydrophilic moieties of glycoproteins, N-glycans play important roles in protein stability. They protect the proteins against proteolytic degradation, aggregation, and thermal denaturation through maintaining optimal conformations. There are extensive evidences showing the involvement of N-glycans in the pharmacodynamics and pharmacokinetics of recombinant therapeutic proteins and antibodies. Highly sialylated complex-type glycans enable the longer serum half-lives of proteins against uptake through hepatic asialoglycoprotein receptor and mannose receptor for degradation in lysosomes. Moreover, the presence of nonhuman glycans results in clearance through pre-existing antibodies from serum and induces IgE-mediated anaphylaxis. N-glycans also facilitate or reduce the adverse immune responses of the proteins through interacting with multiple glycan-binding proteins, including those specific for mannose or mannose 6-phosphate. Due to the glycan impacts, a few therapeutic proteins were glycoengineered to improve the pharmacokinetics and stability. Thus, N-glycosylation should be extensively investigated and optimized for each individual protein for better efficacy and safety.

Use of Mass Spectrometry to Screen Glycan Early Markers in Hepatocellular Carcinoma

Association between altered glycosylation patterns and poor prognosis in cancer points glycans as potential specific tumor markers. Most proteins are glycosylated and functionally arranged on cell surface and extracellular matrix, mediating interactions and cellular signaling. Thereby, aberrant glycans may be considered a pathological phenotype at least as important as changes in protein expression for cancer and other complex diseases. As most serum glycoproteins have hepatic origin, liver disease phenotypes, such as hepatocellular carcinoma (HCC), may present altered glycan profile and display important modifications. One of the prominent obstacles in HCC is the diagnostic in advanced stages when patients have several liver dysfunctions, limiting treatment options and life expectancy. The characterization of glycomic profiles in pathological conditions by means of mass spectrometry (MS) may lead to the discovery of early diagnostic markers using non-invasive approaches. MS is a powerful analytical technique capable of elucidating many glycobiological issues and overcome limitations of the serological markers currently applied in clinical practice. Therefore, MS-based glycomics of tumor biomarkers is a promising tool to increase early detection and monitoring of disease.

Evolution of the magic bullet: Single chain antibody fragments for the targeted delivery of immunomodulatory proteins

Immunocytokines are fusion proteins that combine the specific antigen binding capacities of an antibody or derivative thereof and the potent bioactivity of a cytokine partner. These novel biopharmaceuticals have been directed to various targets of oncological as well as non-oncological origin and a handful of promising constructs are currently advancing in the clinical trial pipeline. Several factors such as the choice of a disease specific antigen, the antibody format and the modulatory nature of the payload are crucial, not only for therapeutic efficacy and safety but also for the commercial success of such a product. In this review, we provide an overview of the basic principles and obstacles in immunocytokine design with a specific focus on single chain antibody fragment-based constructs that employ interleukins as the immunoactive component. Impact statement Selective activation of the immune system in a variety of malignancies represents an attractive approach when existing strategies have failed to provide adequate treatment options. Immunocytokines as a novel class of bifunctional protein therapeutics have emerged recently and generated promising results in preclinical and clinical studies. In order to harness their full potential, multiple different aspects have to be taken into consideration. Several key points of these fusion constructs are discussed here and should provide an outline for the development of novel products based on an overview of selected formats.

Navigating tissue chips from development to dissemination: A pharmaceutical industry perspective

Tissue chips are poised to deliver a paradigm shift in drug discovery. By emulating human physiology, these chips have the potential to increase the predictive power of preclinical modeling, which in turn will move the pharmaceutical industry closer to its aspiration of clinically relevant and ultimately animal-free drug discovery. Despite the tremendous science and innovation invested in these tissue chips, significant challenges remain to be addressed to enable their routine adoption into the industrial laboratory. This article describes the main steps that need to be taken and highlights key considerations in order to transform tissue chip technology from the hands of the innovators into those of the industrial scientists. Written by scientists from 13 pharmaceutical companies and partners at the National Institutes of Health, this article uniquely captures a consensus view on the progression strategy to facilitate and accelerate the adoption of this valuable technology. It concludes that success will be delivered by a partnership approach as well as a deep understanding of the context within which these chips will actually be used. Impact statement The rapid pace of scientific innovation in the tissue chip (TC) field requires a cohesive partnership between innovators and end users. Near term uptake of these human-relevant platforms will fill gaps in current capabilities for assessing important properties of disposition, efficacy and safety liabilities. Similarly, these platforms could support mechanistic studies which aim to resolve challenges later in development (e.g. assessing the human relevance of a liability identified in animal studies). Building confidence that novel capabilities of TCs can address real world challenges while they themselves are being developed will accelerate their application in the discovery and development of innovative medicines. This article outlines a strategic roadmap to unite innovators and end users thus making implementation smooth and rapid. With the collective contributions from multiple international pharmaceutical companies and partners at National Institutes of Health, this article should serve as an invaluable resource to the multi-disciplinary field of TC development.

Enhancing glycan isomer separations with metal ions and positive and negative polarity ion mobility spectrometry-mass spectrometry analyses

Glycomics has become an increasingly important field of research since glycans play critical roles in biology processes ranging from molecular recognition and signaling to cellular communication. Glycans often conjugate with other biomolecules, such as proteins and lipids, and alter their properties and functions, so glycan characterization is essential for understanding the effects they have on cellular systems. However, the analysis of glycans is extremely difficult due to their complexity and structural diversity (i.e., the number and identity of monomer units, and configuration of their glycosidic linkages and connectivities). In this work, we coupled ion mobility spectrometry with mass spectrometry (IMS-MS) to characterize glycan standards and biologically important isomers of synthetic αGal-containing O-glycans including glycotopes of the protozoan parasite Trypanosoma cruzi, which is the causative agent of Chagas disease. IMS-MS results showed significant differences for the glycan structural isomers when analyzed in positive and negative polarity and complexed with different metal cations. These results suggest that specific metal ions or ion polarities could be used to target and baseline separate glycan isomers of interest with IMS-MS. Graphical abstract Glycan isomers, such as fructose and glucose, show distinct separations in positive and negative ion mode.

Antibody-Based Targeted Delivery of Interleukin-22 Promotes Rapid Clinical Recovery in Mice With DSS-Induced Colitis

BACKGROUND

We have recently described the potential of the alternatively spliced extradomain A of fibronectin as a target for antibody-based pharmacodelivery applications in ulcerative colitis. Here, we report on the cloning and therapeutic properties of novel antibody-based fusion proteins, comprising the F8 antibody specific to extradomain A and murine interleukin (IL)-22, a globular cytokine belonging to the IL10 family. A protective function for IL22 in colitis has previously been described, as this cytokine induces antimicrobial, proliferative, and antiapoptotic pathways, preventing tissue damage and promoting epithelial repair.

METHODS

Two fusion proteins comprising IL22, fused at the N- or at the C-terminus of the F8 antibody in diabody format, were expressed in mammalian cells. The ability of radiolabeled preparations of the 2 fusion proteins to localize at sites of disease was assessed by autoradiography in a murine model of dextran sodium sulfate-induced colitis and by quantitative biodistribution analysis in a syngeneic mouse teratocarcinoma model. Therapeutic activity was assessed in mice with dextran sodium sulfate-induced colitis, which received intravenous injections of antibody-cytokine fusion proteins.

RESULTS

Both fusion proteins were able to selectively accumulate at the site of disease. The fusion protein with the cytokine moiety at the N-terminal extremity (IL22-F8) exhibited better results than the C-terminal fusion, both in terms of targeting selectivity and therapeutic efficacy. Mice treated with IL22-F8 showed a more rapid recovery from clinical symptoms compared with controls and improved macroscopic and microscopic morphology of the colon.

CONCLUSIONS

IL22-F8 is a promising biopharmaceutical drug candidate for the treatment of ulcerative colitis.

Targeted Reconstitution of Cytokine Activity upon Antigen Binding using Split Cytokine Antibody Fusion Proteins

The targeted assembly of antibody products upon antigen binding represents a novel strategy for the reconstitution of potent therapeutic activity at the site of disease, sparing healthy tissues. We demonstrate that interleukin-12, a heterodimeric pro-inflammatory cytokine consisting of the disulfide-linked p40 and p35 subunits, can be reconstituted by sequential reassembly of fusion proteins based on antibody fragments and interleukin-12 subunit mutants. Analysis of the immunostimulatory properties of interleukin-12 and its derivatives surprisingly revealed that the mutated p35 subunit partially retained the activity of the parental cytokine, whereas the p40 subunit alone was not able to stimulate T cells or natural killer cells. The concept of stepwise antibody-based reassembly of split cytokines could be useful for the development of other anticancer therapeutics with improved safety and tolerability.

Different tissue distribution properties for glycosylation variants of fusion proteins containing the p40 subunit of murine interleukin-12

Antibody-based fusion proteins are gaining increasing importance for therapeutic applications, but the impact of glycosylation on in vivo biopharmaceutical performance is not always completely understood. In this article, we have analyzed biochemical and pharmaceutical properties of fusion proteins, consisting of the F8 antibody (specific to the EDA domain of fibronectin, a marker of tissue remodeling and of angiogenesis) and of the p40 subunit of interleukin-12, an inhibitor of inflammation. The corresponding fusion protein (F8-IL12p40), which inhibits colitis development in mice, is a glycosylated protein with suboptimal disease targeting properties in vivo Since the protein was extensively glycosylated, as evidenced by PNGase F treatment and mass spectrometric analysis, we mutated four asparagine residues in various combinations. The corresponding proteins exhibited similar biochemical and antigen-binding properties, but differences in thermal stability and bioactivity. Asparagine mutations did not lead to recovery of disease targeting performance in vivo, as evidenced by quantitative biodistribution studies with radioiodinated protein preparations in tumor-bearing mice. By contrast, an almost complete recovery of targeting was achieved with an enzymatically deglycosylated protein preparation. These findings reinforce the concept that different glycostructures can have an impact on tissue distribution properties.

Comprehensive N-Glycan Profiling of Avian Immunoglobulin Y

Recent exploitation of the avian immune system has highlighted its suitability for the generation of high-quality, high-affinity antibodies to a wide range of antigens for a number of therapeutic and biotechnological applications. The glycosylation profile of potential immunoglobulin therapeutics is species specific and is heavily influenced by the cell-line/culture conditions used for production. Hence, knowledge of the carbohydrate moieties present on immunoglobulins is essential as certain glycan structures can adversely impact their physicochemical and biological properties. This study describes the detailed N-glycan profile of IgY polyclonal antibodies from the serum of leghorn chickens using a fully quantitative high-throughput N-glycan analysis approach, based on ultra-performance liquid chromatography (UPLC) separation of released glycans. Structural assignments revealed serum IgY to contain complex bi-, tri- and tetra-antennary glycans with or without core fucose and bisects, hybrid and high mannose glycans. High sialic acid content was also observed, with the presence of rare sialic acid structures, likely polysialic acids. It is concluded that IgY is heavily decorated with complex glycans; however, no known non-human or immunogenic glycans were identified. Thus, IgY is a potentially promising candidate for immunoglobulin-based therapies for the treatment of various infectious diseases.

Immunocytokines for cancer treatment: past, present and future

Immunocytokines are antibody-cytokine fusion proteins, with the potential to preferentially localize on tumor lesions and to activate anticancer immunity at the site of disease. Various tumor targets (e.g., cell membrane antigens and extracellular matrix components) and antibody formats (e.g., intact IgG and antibody fragments) have been considered for immunocytokine development and some products have advanced to clinical trials. In this review, we present relevant concepts and strategies for the design and use of anticancer immunocytokine products. In addition, we discuss emerging strategies for the pharmaceutical development and clinical application of this promising class of biopharmaceuticals.

Immunocytokines and bispecific antibodies: two complementary strategies for the selective activation of immune cells at the tumor site

The activation of the immune system for a selective removal of tumor cells represents an attractive strategy for the treatment of metastatic malignancies, which cannot be cured by existing methodologies. In this review, we examine the design and therapeutic potential of immunocytokines and bispecific antibodies, two classes of bifunctional products which can selectively activate the immune system at the tumor site. Certain protein engineering aspects, such as the choice of the antibody format, are common to both classes of therapeutic agents and can have a profound impact on tumor homing performance in vivo of individual products. However, immunocytokines and bispecific antibodies display different mechanisms of action. Future research activities will reveal whether an additive of even synergistic benefit can be obtained from the judicious combination of these two types of biopharmaceutical agents.

Immunocytokines: a novel class of products for the treatment of chronic inflammation and autoimmune conditions

Antibody-cytokine fusion proteins, often referred to as immunocytokines, represent a novel class of biopharmaceutical agents that combine the disease-homing activity of certain antibodies with the immunomodulatory properties of cytokine payloads. Originally, immunocytokines were mainly developed for cancer therapy applications. More recently, however, the use of anti-inflammatory cytokines for the treatment of chronic inflammatory conditions and to treat autoimmune diseases has been considered. This review analyzes basic principles in the design of immunocytokines and describes the most advanced products in preclinical and clinical development.

XBP1s Links the Unfolded Protein Response to the Molecular Architecture of Mature N-Glycans

The molecular architecture of the mature N-glycome is dynamic, with consequences for both normal and pathologic processes. Elucidating cellular mechanisms that modulate the N-linked glycome is, therefore, crucial. The unfolded protein response (UPR) is classically responsible for maintaining proteostasis in the secretory pathway by defining levels of chaperones and quality control proteins. Here, we employ chemical biology methods for UPR regulation to show that stress-independent activation of the UPR's XBP1s transcription factor also induces a panel of N-glycan maturation-related enzymes. The downstream consequence is a distinctive shift toward specific hybrid and complex N-glycans on N-glycoproteins produced from XBP1s-activated cells, which we characterize by mass spectrometry. Pulse-chase studies attribute this shift specifically to altered N-glycan processing, rather than to changes in degradation or secretion rates. Our findings implicate XBP1s in a new role for N-glycoprotein biosynthesis, unveiling an important link between intracellular stress responses and the molecular architecture of extracellular N-glycoproteins.