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

Tenascin-C targeting strategies in cancer

Tenascin-C (TNC) is a matricellular and multimodular glycoprotein highly expressed under pathological conditions, especially in cancer and chronic inflammatory diseases. Since a long time TNC is considered as a promising target for diagnostic and therapeutic approaches in anti-cancer treatments and was already extensively targeted in clinical trials on cancer patients. This review provides an overview of the current most advanced strategies used for TNC detection and anti-TNC theranostic approaches including some advanced clinical strategies. We also discuss novel treatment protocols, where targeting immune modulating functions of TNC could be center stage.

Anti-VEGFR2-Interferon α Promotes the Infiltration of CD8+ T Cells in Colorectal Cancer by Upregulating the Expression of CCL5

SUMMARY

Immunocytokines are a promising immunotherapeutic approach in cancer therapy. Anti-VEGFR2-interferon α (IFNα) suppressed colorectal cancer (CRC) growth and enhanced CD8+ T-cell infiltration in the tumor microenvironment, exhibiting great clinical translational potential. However, the mechanism of how the anti-VEGFR2-IFNα recruits T cells has not been elucidated. Here, we demonstrated that anti-VEGFR2-IFNα suppressed CRC metastasis and enhanced CD8+ T-cell infiltration. RNA sequencing revealed a transcriptional activation of CCL5 in metastatic CRC cells, which was correlated with T-cell infiltration. IFNα but not anti-VEGFR2 could further upregulate CCL5 in tumors. In immunocompetent mice, both IFNα and anti-VEGFR2-IFNα increased the subset of tumor-infiltrating CD8+ T cells through upregulation of CCL5. Knocking down CCL5 in tumor cells attenuated the infiltration of CD8+ T cells and dampened the antitumor efficacy of anti-VEGFR2-IFNα treatment. We, therefore, propose upregulation of CCL5 is a key to enhance infiltration of CD8+ T cells in metastatic CRC with IFNα and IFNα-based immunocytokine treatments. These findings may help the development of IFNα related immune cytokines for the treatment of less infiltrated tumors.

Obinutuzumab Pretreatment as a Novel Approach to Mitigate Formation of Anti-Drug Antibodies Against Cergutuzumab Amunaleukin in Patients with Solid Tumors

PURPOSE

The immunocytokine cergutuzumab amunaleukin (CEA-IL2v) showed manageable safety and favorable pharmacodynamics in phase I/Ib trials in patients with advanced/metastatic carcinoembryonic antigen-positive (CEA+) solid tumors, but this was accompanied by a high incidence of anti-drug antibodies (ADA). We examined B-cell depletion with obinutuzumab as a potential mitigation strategy.

EXPERIMENTAL DESIGN

Preclinical data comparing B-cell depletion with rituximab versus obinutuzumab are summarized. Substudies of phase I/Ib trials investigated the effect of obinutuzumab pretreatment on ADA development, safety, pharmacodynamics, and antitumor activity of CEA-IL2v ± atezolizumab in patients with advanced/metastatic or unresectable CEA+ solid tumors who had progressed on standard of care.

RESULTS

Preclinical data showed superior B-cell depletion with obinutuzumab versus rituximab. In clinical studies, patients received CEA-IL2v monotherapy with (n = 16) or without (n = 6) obinutuzumab pretreatment (monotherapy study), or CEA-IL2v + atezolizumab + obinutuzumab pretreatment (n = 5; combination study). In the monotherapy study, after four cycles (every 2 weeks treatment), 0/15 evaluable patients administered obinutuzumab pretreatment had ADAs versus 4/6 patients without obinutuzumab. Obinutuzumab pretreatment with CEA-IL2v monotherapy showed no new safety signals and pharmacodynamic data suggested minimal impact on T cells and natural killer cells. Conversely, increased liver toxicity was observed in the combination study (CEA-IL2v + atezolizumab + obinutuzumab pretreatment).

CONCLUSIONS

These preliminary findings suggest that obinutuzumab pretreatment before CEA-IL2v administration in patients with CEA+ solid tumors may be a feasible and potent ADA mitigation strategy, with an acceptable safety profile, supporting broader investigation of obinutuzumab pretreatment for ADA mitigation in other settings.

Nanobodies in cytokine‑mediated immunotherapy and immunoimaging (Review)

Cytokines are the main regulators of innate and adaptive immunity, mediating communications between the cells of the immune system and regulating biological functions, including cell motility, differentiation, growth and apoptosis. Cytokines and cytokine receptors have been used in the treatment of tumors and autoimmune diseases, and to intervene in cytokine storms. Indeed, the use of monoclonal antibodies to block cytokine‑receptor interactions, as well as antibody‑cytokine fusion proteins has exhibited immense potential for the treatment of tumors and autoimmune diseases. Compared with these traditional types of antibodies, nanobodies not only maintain a high affinity and specificity, but also have the advantages of high thermal stability, a high capacity for chemical manipulation, low immunogenicity, good tissue permeability, rapid clearance and economic production. Thus, nanobodies have extensive potential for use in the diagnosis and treatment of cytokine‑related diseases. The present review summarizes the application of nanobodies in cytokine‑mediated immunotherapy and immunoimaging.

Engineering Anticytokine Antibodies for Immune Modulation

The delicate balance of immune homeostasis is regulated by the interactions between cytokines and their cognate cell surface signaling receptors. There is intensive interest in harnessing cytokines as drugs for diseases such as cancer and autoimmune disorders. However, the multifarious and often contradictory activities of cytokines, coupled with their short serum half-lives, limit clinical performance and result in dangerous toxicities. There is thus growing emphasis on manipulating natural cytokines to enhance their selectivity, safety, and durability through various strategies. One strategy that has gained traction in recent years is the development of anticytokine Abs that not only extend the circulation half-life of cytokines but also specifically bias their immune activities through multilayered molecular mechanisms. Although Abs are notorious for their antagonistic activities, this review focuses on anticytokine Abs that selectively agonize the activity of the target protein. This approach has potential to help realize the clinical promise of cytokine-based therapies.

Navigating the Cytokine Seas: Targeting Cytokine Signaling Pathways in Cancer Therapy

Cancer remains one of the leading causes of morbidity and mortality worldwide, necessitating continuous efforts to develop effective therapeutic strategies. Over the years, advancements in our understanding of the complex interplay between the immune system and cancer cells have led to the development of immunotherapies that revolutionize cancer treatment. Cytokines, as key regulators of the immune response, are involved in both the initiation and progression of cancer by affecting inflammation and manipulating multiple intracellular signaling pathways that regulate cell growth, proliferation, and migration. Cytokines, as key regulators of inflammation, have emerged as promising candidates for cancer therapy. This review article aims to provide an overview of the significance of cytokines in cancer development and therapy by highlighting the importance of targeting cytokine signaling pathways as a potential therapeutic approach.

ADCdb: the database of antibody-drug conjugates

Antibody-drug conjugates (ADCs) are a class of innovative biopharmaceutical drugs, which, via their antibody (mAb) component, deliver and release their potent warhead (a.k.a. payload) at the disease site, thereby simultaneously improving the efficacy of delivered therapy and reducing its off-target toxicity. To design ADCs of promising efficacy, it is crucial to have the critical data of pharma-information and biological activities for each ADC. However, no such database has been constructed yet. In this study, a database named ADCdb focusing on providing ADC information (especially its pharma-information and biological activities) from multiple perspectives was thus developed. Particularly, a total of 6572 ADCs (359 approved by FDA or in clinical trial pipeline, 501 in preclinical test, 819 with in-vivo testing data, 1868 with cell line/target testing data, 3025 without in-vivo/cell line/target testing data) together with their explicit pharma-information was collected and provided. Moreover, a total of 9171 literature-reported activities were discovered, which were identified from diverse clinical trial pipelines, model organisms, patient/cell-derived xenograft models, etc. Due to the significance of ADCs and their relevant data, this new database was expected to attract broad interests from diverse research fields of current biopharmaceutical drug discovery. The ADCdb is now publicly accessible at: https://idrblab.org/adcdb/.

Targeting fusion proteins of the interleukin family: A promising new strategy for the treatment of autoinflammatory diseases

As a means of communication between immune cells and non-immune cells, Interleukins (ILs) has the main functions of stimulating the proliferation and activation of inflammatory immune cells such as dendritic cells and lymphocytes, promote the development of blood cells and so on. However, dysregulation of ILs expression is a major feature of autoinflammatory diseases. The drugs targeting ILs or IL-like biologics have played an important role in the clinical treatment of autoinflammatory diseases. Nevertheless, the widespread use of IL products may result in significant off-target adverse reactions. Thus, there is a clear need to develop next-generation ILs products in the biomedical field. Fusion proteins are proteins created through the joining of two or more genes that originally coded for separate proteins. Over the last 30 years, there has been increasing interest in the use of fusion protein technology for developing anti-inflammatory drugs. In comparison to single-target drugs, fusion proteins, as multiple targets drugs, have the ability to enhance the cytokine therapeutic index, resulting in improved efficacy over classical drugs. The strategy of preparing ILs or their receptors as fusion proteins is increasingly used in the treatment of autoimmune and chronic inflammation. This review focuses on the efficacy of several fusion protein drugs developed with ILs or their receptors in the treatment of autoinflammatory diseases, in order to illustrate the prospects of this new technology as an anti-inflammatory drug development protocol in the future.

Next generation of multispecific antibody engineering

Multispecific antibodies recognize two or more epitopes located on the same or distinct targets. This added capability through protein design allows these man-made molecules to address unmet medical needs that are no longer possible with single targeting such as with monoclonal antibodies or cytokines alone. However, the approach to the development of these multispecific molecules has been met with numerous road bumps, which suggests that a new workflow for multispecific molecules is required. The investigation of the molecular basis that mediates the successful assembly of the building blocks into non-native quaternary structures will lead to the writing of a playbook for multispecifics. This is a must do if we are to design workflows that we can control and in turn predict success. Here, we reflect on the current state-of-the-art of therapeutic biologics and look at the building blocks, in terms of proteins, and tools that can be used to build the foundations of such a next-generation workflow.

Therapeutic Fusion Proteins

Therapeutic fusion proteins are a class of hybrid constructs that combine distinct biomolecules into a single platform with the additive effects of the components. The ability to fuse two unrelated proteins provides a means to localize mechanisms to better treat a range of diseases. Fusion proteins can be designed to impart diverse functions, including increasing half-life, providing targeting, and enabling sustained signaling. Of these, half-life extenders, which are fused to a therapeutic protein to increase exposure, are the most established group of fusion proteins, with many clinical successes. Rapid advances in antibody and antibody-derivative technology have enabled the fusion of targeting domains with therapeutic proteins. An emerging group of therapeutic fusion proteins has two separate active functions. Although most research for therapeutic fusion proteins focuses on cancer, prior successes provide a foundation for studies into other diseases as well. The exponential emergence of biopharmaceuticals gives precedence for increased research into therapeutic fusion proteins for a multitude of diseases.

Antibody-drug conjugates come of age in oncology

Antibody-drug conjugates (ADCs) combine the specificity of monoclonal antibodies with the potency of highly cytotoxic agents, potentially reducing the severity of side effects by preferentially targeting their payload to the tumour site. ADCs are being increasingly used in combination with other agents, including as first-line cancer therapies. As the technology to produce these complex therapeutics has matured, many more ADCs have been approved or are in late-phase clinical trials. The diversification of antigenic targets as well as bioactive payloads is rapidly broadening the scope of tumour indications for ADCs. Moreover, novel vector protein formats as well as warheads targeting the tumour microenvironment are expected to improve the intratumour distribution or activation of ADCs, and consequently their anticancer activity for difficult-to-treat tumour types. However, toxicity remains a key issue in the development of these agents, and better understanding and management of ADC-related toxicities will be essential for further optimization. This Review provides a broad overview of the recent advances and challenges in ADC development for cancer treatment.

Advances in engineering and delivery strategies for cytokine immunotherapy

INTRODUCTION

Cytokine immunotherapy is a growing field for the treatment of cancer, infectious disease, autoimmunity, and other ailments. Therapeutic cytokines are a class of secreted, small proteins that play a pivotal role in regulating the innate and adaptive immune system by provoking or mitigating immune responses. In the clinic, cytokines are frequently combined with other treatments, such as small molecules and monoclonal antibodies. However, the clinical translation of cytokine therapies is hindered by their short half-life, pleiotropic nature, and off-target effects, which cause diminished efficacy and severe systemic toxicity. Such toxicity limits dosage, thus resulting in suboptimal doses. Accordingly, numerous efforts have been devoted to exploring strategies to promote cytokine therapies by improving their tissue specificity and pharmacokinetics.

AREAS COVERED

Preclinical and clinical research into bioengineering and delivery strategies for cytokines, consisting of bioconjugation, fusion proteins, nanoparticles, and scaffold-based systems.

EXPERT OPINION

These approaches pave the way for the development of next-generation cytokine treatments with greater clinical benefit and reduced toxicity, circumventing such issues currently associated with cytokine therapy.

Enabling the formation of native mAb, Fab' and Fc-conjugates using a bis-disulfide bridging reagent to achieve tunable payload-to-antibody ratios (PARs)

Either as full IgGs or as fragments (Fabs, Fc, etc.), antibodies have received tremendous attention in the development of new therapeutics such as antibody-drug conjugates (ADCs). The production of ADCs involves the grafting of active payloads onto an antibody, which is generally enabled by the site-selective modification of native or engineered antibodies via chemical or enzymatic methods. Whatever method is employed, controlling the payload-antibody ratio (PAR) is a challenge in terms of multiple aspects including: (i) obtaining homogeneous protein conjugates; (ii) obtaining unusual PARs (PAR is rarely other than 2, 4 or 8); (iii) using a single method to access a range of different PARs; (iv) applicability to various antibody formats; and (v) flexibility for the production of heterofunctional antibody-conjugates (e.g. attachment of multiple types of payloads). In this article, we report a single pyridazinedione-based trifunctional dual bridging linker that enables, in a two-step procedure (re-bridging/click), the generation of either mAb-, Fab'-, or Fc-conjugates from native mAb, (Fab')2 or Fc formats, respectively. Fc and (Fab')2 formats were generated via enzymatic digestion of native mAbs. Whilst the same reduction and re-bridging protocols were applied to all three of the protein formats, the subsequent click reaction(s) employed to graft payload(s) drove the generation of a range of PARs, including heterofunctional PARs. As such, exploiting click reactivity and/or orthogonality afforded mAb-conjugates with PARs of 6, 4, 2 or 4 + 2, and Fab'- and Fc-conjugates with a PAR of 3, 2, 1 or 2 + 1 on-demand. We believe that the homogeneity, novelty and variety in accessible PARs, as well as the applicability to various antibody-conjugate formats enabled by our non-recombinant method could be a suitable tool for antibody-drug conjugates optimisation (optimal PAR value, optimal payloads combination) and boost the development of new antibody therapeutics (Fab'- and Fc-conjugates).

Targeted Interleukin-9 delivery in pulmonary hypertension: Comparison of immunocytokine formats and effector cell study

AIMS

Pulmonary hypertension (PH) is accompanied by pulmonary vascular remodelling. By targeted delivery of Interleukin-9 (IL9) via the immunocytokine F8IL9, beneficial effects could be demonstrated in a mouse model of PH. This study aimed to compare two immunocytokine formats (single-chain Fv and full IgG) and to identify potential target cells of IL9.

METHODS

The Monocrotaline mouse model of PH (PH, n = 12) was chosen to evaluate the treatment effects of F8IL9F8 (n = 12) and F8IgGIL9 (n = 6) compared with sham-induced animals (control, n = 10), the dual endothelin receptor antagonist Macitentan (MAC, n = 12) or IL9-based immunocytokines with irrelevant antigen specificity (KSFIL9KSF, n = 12; KSFIgGIL9 n = 6). Besides comparative validation of treatment effects, the study was focused on the detection and quantification of mast cells (MCs) and regulatory T cells (Tregs).

RESULTS

There was a significantly elevated systolic right ventricular pressure (104 ± 36 vs. 45 ± 17 mmHg) and an impairment of right ventricular echocardiographic parameters (RVbasal: 2.52 ± 0.25 vs. 1.94 ± 0.13 mm) in untreated PH compared with controls (p < 0.05). Only the groups treated with F8IL9, irrespective of the format, showed consistent beneficial effects (p < 0.05). Moreover, F8IL9F8 but not F8IgGIL9 treatment significantly reduced lung tissue damage compared with untreated PH mice (p < 0.05). There was a significant increase in Tregs in F8IL9-treated compared with control animals, the untreated PH and the MAC group (p < 0.05).

CONCLUSIONS

Beneficial treatment effects of targeted IL9 delivery in a preclinical model of PH could be convincingly validated. IL9-mediated recruitment of Tregs into lung tissue might play a crucial role in the induction of anti-inflammatory and anti-proliferative mechanisms potentially contributing to a novel disease-modifying concept.

Generation and in vivo characterization of a novel high-affinity human antibody targeting carcinoembryonic antigen

There are no effective treatment options for most patients with metastatic colorectal cancer (mCRC). mCRC remains a leading cause of tumor-related death, with a five-year survival rate of only 15%, highlighting the urgent need for novel pharmacological products. Current standard drugs are based on cytotoxic chemotherapy, VEGF inhibitors, EGFR antibodies, and multikinase inhibitors. The antibody-based delivery of pro-inflammatory cytokines provides a promising and differentiated strategy to improve the treatment outcome for mCRC patients. Here, we describe the generation of a novel fully human monoclonal antibody (termed F4) targeting the carcinoembryonic antigen (CEA), a tumor-associated antigen overexpressed in colorectal cancer and other malignancies. The F4 antibody was selected by antibody phage display technology after two rounds of affinity maturation. F4 in single-chain variable fragment format bound to CEA in surface plasmon resonance with an affinity of 7.7 nM. Flow cytometry and immunofluorescence on human cancer specimens confirmed binding to CEA-expressing cells. F4 selectively accumulated in CEA-positive tumors, as evidenced by two orthogonal in vivo biodistribution studies. Encouraged by these results, we genetically fused murine interleukin (IL) 12 to F4 in the single-chain diabody format. F4-IL12 exhibited potent antitumor activity in two murine models of colon cancer. Treatment with F4-IL12 led to an increased density of tumor-infiltrating lymphocytes and an upregulation of interferon γ expression by tumor-homing lymphocytes. These data suggest that the F4 antibody is an attractive delivery vehicle for targeted cancer therapy.

Generation and engineering of potent single domain antibody-based bispecific IL-18 mimetics resistant to IL-18BP decoy receptor inhibition

Here, we generated bispecific antibody (bsAb) derivatives that mimic the function of interleukin (IL)-18 based on single domain antibodies (sdAbs) specific to IL-18 Rα and IL-18 Rβ. For this, camelids were immunized, followed by yeast surface display (YSD)-enabled discovery of VHHs targeting the individual receptor subunits. Upon reformatting into a strictly monovalent (1 + 1) bispecific sdAb architecture, several bsAbs triggered dose-dependent IL-18 R downstream signaling on IL-18 reporter cells, as well as IFN-γ release by peripheral blood mononuclear cells in the presence of low-dose IL-12. However, compared with IL-18, potencies and efficacies were considerably attenuated. By engineering paratope valencies and the spatial orientation of individual paratopes within the overall design architecture, we were able to generate IL-18 mimetics displaying significantly augmented functionalities, resulting in bispecific cytokine mimetics that were more potent than IL-18 in triggering proinflammatory cytokine release. Furthermore, generated IL-18 mimetics were unaffected from inhibition by IL-18 binding protein decoy receptor. Essentially, we demonstrate that this strategy enables the generation of IL-18 mimetics with tailor-made cytokine functionalities.

Transforming growth factor-β signaling: from tumor microenvironment to anticancer therapy

Transforming growth factor-β (TGF-β) signaling is an important pathway for promoting the pathogenesis of inflammatory diseases, including cancer. The roles of TGF-β signaling are heterogeneous and versatile in cancer development and progression, both anticancer and protumoral actions are reported. Interestingly, increasing evidence suggests that TGF-β enhances disease progression and drug resistance via immune-modulatory actions in the tumor microenvironment (TME) of solid tumors. A better understanding of its regulatory mechanisms in the TME at the molecular level can facilitate the development of precision medicine to block the protumoral actions of TGF-β in the TME. Here, the latest information about the regulatory mechanisms and translational research of TGF-β signaling in the TME for therapeutic development had been summarized.

The application of Interleukin-2 family cytokines in tumor immunotherapy research

The Interleukin-2 Family contains six kinds of cytokines, namely IL-2, IL-15, IL-4, IL-7, IL-9, and IL-21, all of which share a common γ chain. Many cytokines of the IL-2 family have been reported to be a driving force in immune cells activation. Therefore, researchers have tried various methods to study the anti-tumor effect of cytokines for a long time. However, due to the short half-life, poor stability, easy to lead to inflammatory storms and narrow safety treatment window of cytokines, this field has been tepid. In recent years, with the rapid development of protein engineering technology, some engineered cytokines have a significant effect in tumor immunotherapy, showing an irresistible trend of development. In this review, we will discuss the current researches of the IL-2 family and mainly focus on the application and achievements of engineered cytokines in tumor immunotherapy.

Therapeutic antibodies for precise cancer immunotherapy: current and future perspectives

Antibodies, as one of the most important components of host adaptive immune system, play an important role in defense of infectious disease, immune surveillance, and autoimmune disease. Due to the development of recombinant antibody technology, antibody therapeutics become the largest and rapidly expanding drug to provide major health benefits to patients, especially for the treatment of cancer patients. Many antibody-based therapeutic strategies have been developed including monoclonal antibodies, antibody-drug conjugates, bispecific and trispecific antibodies and pro-antibodies with promising results from both clinical and pre-clinical trials. However, the response rate and side-effect still vary between patients with undefined mechanisms. Here, we summarized the current and future perspectives of antibody-based cancer immunotherapeutic strategies for designing next-generation drugs.

Intratumoral nanobody-IL-2 fusions that bind the tumor extracellular matrix suppress solid tumor growth in mice

Confining cytokine exposure to the tumors would greatly enhance cancer immunotherapy safety and efficacy. Immunocytokines, cytokines fused to tumor-targeting antibodies, have been developed with this intention, but without significant clinical success to date. A critical limitation is uptake by receptor-expressing cells in the blood, that decreases the dose at the tumor and engenders toxicity. Small-format immunocytokines, constructed with antibody fragments, are hypothesized to improve tumor specificity due to rapid systemic clearance. However, effective design criteria for small-format immunocytokines need further examination. Here, we engineer small interleukin-2 (IL-2) immunocytokines fused to nanobodies with nanomolar to picomolar affinities for the tumor-specific EIIIB domain of fibronectin (also known as EDB). Upon intravenous delivery into immunocompetent mice, such immunocytokines led to similar tumor growth delay as size-matched untargeted IL-2. Intratumoral (i.t.) delivery imparted improved survival dependent on affinity to EIIIB. I.t. administration offers a promising avenue to deliver small-format immunocytokines, given effective affinity for the tumor microenvironment.

Multifunctional NK Cell–Engaging Antibodies Targeting EGFR and NKp30 Elicit Efficient Tumor Cell Killing and Proinflammatory Cytokine Release

In this work, we have generated novel Fc-comprising NK cell engagers (NKCEs) that bridge human NKp30 on NK cells to human epidermal growth factor receptor (EGFR) on tumor cells. Camelid-derived VHH single-domain Abs specific for human NKp30 and a humanized Fab derived from the EGFR-specific therapeutic Ab cetuximab were used as binding arms. By combining camelid immunization with yeast surface display, we were able to isolate a diverse panel of NKp30-specific VHHs against different epitopes on NKp30. Intriguingly, NKCEs built with VHHs that compete for binding to NKp30 with B7-H6, the natural ligand of NKp30, were significantly more potent in eliciting tumor cell lysis of EGFR-positive tumor cells than NKCEs harboring VHHs that target different epitopes on NKp30 from B7-H6. We demonstrate that the NKCEs can be further improved with respect to killing capabilities by concomitant engagement of FcγRIIIa and that soluble B7-H6 does not impede cytolytic capacities of all scrutinized NKCEs at significantly higher B7-H6 concentrations than observed in cancer patients. Moreover, we show that physiological processes requiring interactions between membrane-bound B7-H6 and NKp30 on NK cells are unaffected by noncompeting NKCEs still eliciting tumor cell killing at low picomolar concentrations. Ultimately, the NKCEs generated in this study were significantly more potent in eliciting NK cell–mediated tumor cell lysis than cetuximab and elicited a robust release of proinflammatory cytokines, both features which might be beneficial for antitumor therapy.

Impact of glycoengineering and antidrug antibodies on the anticancer activity of a plant-made lectin-Fc fusion protein

Plants are an efficient production platform for manufacturing glycoengineered monoclonal antibodies and antibody-like molecules. Avaren-Fc (AvFc) is a lectin-Fc fusion protein or lectibody produced in Nicotiana benthamiana, which selectively recognizes cancer-associated high-mannose glycans. In this study, we report the generation of a glycovariant of AvFc that is devoid of plant glycans, including the core α1,3-fucose and β1,2-xylose residues. The successful removal of these glycans was confirmed by glycan analysis using HPLC. This variant, AvFc^ΔXF , has significantly higher affinity for Fc gamma receptors and induces higher levels of luciferase expression in an antibody-dependent cell-mediated cytotoxicity (ADCC) reporter assay against B16F10 murine melanoma cells without inducing apoptosis or inhibiting proliferation. In the B16F10 flank tumour mouse model, we found that systemic administration of AvFc^ΔXF , but not an aglycosylated AvFc variant lacking affinity for Fc receptors, significantly delayed the growth of tumours, suggesting that Fc-mediated effector functions were integral. AvFc^ΔXF treatment also significantly reduced lung metastasis of B16F10 upon intravenous challenge whereas a sugar-binding-deficient mutant failed to show efficacy. Lastly, we determined the impact of antidrug antibodies (ADAs) on drug activity in vivo by pretreating animals with AvFc^ΔXF before implanting tumours. Despite a significant ADA response induced by the pretreatment, we found that the activity of AvFc^ΔXF was unaffected by the presence of these antibodies. These results demonstrate that glycoengineering is a powerful strategy to enhance AvFc's antitumor activity.

Boosting the Liquid Chromatography Separation of Complex Bispecific Antibody Products by Using the Multi-Isocratic Elution Mode

In reversed-phase liquid chromatography (RPLC), the selectivity between major species and minor variants of protein biopharmaceutical products is always limited. Unfortunately, the stationary phase chemistry, type of mobile phase (organic modifier and salts) and temperature only have a very limited impact on selectivity. Therefore, instead of using a linear elution gradient, we evaluated a recently developed strategy, named the multi-isocratic elution mode, to improve the chromatographic resolution. In this contribution, a generic workflow involving the use of an Excel spreadsheet is provided for the rapid and successful development of multi-isocratic elution methods, without the need to use HPLC modeling software. This simple strategy was then successfully applied to very complex biopharmaceutical products; these included one reduced mAb-cytokine fusion protein and a mAb-domain-fusion (C-terminal) protein sample, containing numerous minor variants that were poorly separated from the major species. The addition of several isocratic steps during the chromatographic run provides a clear added value in terms of chromatographic selectivity for several variants, simplifying characterization of the sample with advanced MS tools. In addition to these advantages, some of the limitations of the multi-isocratic elution mode were also highlighted; these included the need to use a highly precise pumping device (preferably, a binary pumping system) and the need to prepare highly accurate mobile phases.

Targeting the Blood–Brain Tumor Barrier with Tumor Necrosis Factor-α

The blood–brain tumor barrier represents a major obstacle for anticancer drug delivery to brain tumors. Thus, novel strategies aimed at targeting and breaching this structure are of great experimental and clinical interest. This review is primarily focused on the development and use of a derivative of tumor necrosis factor-α (TNF) that can target and alter the blood–brain-tumor-barrier. This drug, called NGR-TNF, consists of a TNF molecule fused to the Cys-Asn-Gly-Arg-Cys-Gly (CNGRCG) peptide (called NGR), a ligand of aminopeptidase N (CD13)-positive tumor blood vessels. Results of preclinical studies suggest that this peptide-cytokine fusion product represents a valuable strategy for delivering TNF to tumor vessels in an amount sufficient to break the biological barriers that restrict drug penetration in cancer lesions. Moreover, clinical studies performed in patients with primary central nervous system lymphoma, have shown that an extremely low dose of NGR-TNF (0.8 µg/m²) is sufficient to promote selective blood–brain-tumor-barrier alteration, increase the efficacy of R-CHOP (a chemo-immunotherapy regimen) and improve patient survival. Besides reviewing these findings, we discuss the potential problems related to the instability and molecular heterogeneity of NGR-TNF and review the various approaches so far developed to obtain more robust and homogeneous TNF derivatives, as well as the pharmacological properties of other peptide/antibody-TNF fusion products, muteins and nanoparticles that are potentially useful for targeting the blood–brain tumor barrier. Compared to other TNF-related drugs, the administration of extremely low-doses of NGR-TNF or its derivatives appear as promising non-immunogenic approaches to overcome TNF counter-regulatory mechanism and systemic toxicity, thereby enabling safe breaking of the BBTB.

The use of supercytokines, immunocytokines, engager cytokines, and other synthetic cytokines in immunotherapy

Cytokines exert powerful immunomodulatory effects that are critical to physiology and pathology in humans. The application of natural cytokines in clinical studies has not been clearly established, and there are often problems associated with toxicity or lack of efficacy. The key reasons can be attributed to the pleiotropy of cytokine receptors and undesired activation of off-target cells. With a deeper understanding of the structural principles and functional signals of cytokine-receptor interactions, artificial modification of cytokine signaling through protein engineering and synthetic immunology has become an increasingly feasible and powerful approach. Engineered cytokines are designed to selectively target cells. Herein, the theoretical and experimental evidence of cytokine engineering is reviewed, and the "supercytokines" resulting from structural enhancement and the "immunocytokines" generated by antibody fusion are described. Finally, the "engager cytokines" formed by the crosslinking of cytokines and bispecific immune engagers and other synthetic cytokines formed by nonnatural analogs are also discussed.

Targeting the extracellular matrix for immunomodulation: applications in drug delivery and cell therapies

Host immune cells interact bi-directionally with their extracellular matrix (ECM) to receive and deposit molecular signals, which orchestrate cellular activation, proliferation, differentiation, and function to maintain healthy tissue homeostasis. In response to pathogens or damage, immune cells infiltrate diseased sites and synthesize critical ECM molecules such as glycoproteins, proteoglycans, and glycosaminoglycans to promote healing. When the immune system misidentifies pathogens or fails to survey damaged cells effectively, maladies such as chronic inflammation, autoimmune diseases, and cancer can develop. In these conditions, it is essential to restore balance to the body through modulation of the immune system and the ECM. This review details the components of dysregulated ECM implicated in pathogenic environments and therapeutic approaches to restore tissue homeostasis. We evaluate emerging strategies to overcome inflamed, immune inhibitory, and otherwise diseased microenvironments, including mechanical stimulation, targeted proteases, adoptive cell therapy, mechanomedicine, and biomaterial-based cell therapeutics. We highlight various strategies that have produced efficacious responses in both pre-clinical and human trials and identify additional opportunities to develop next-generation interventions. Significantly, we identify a need for therapies to address dense or fibrotic tissue for the treatment of organ tissue damage and various cancer subtypes. Finally, we conclude that therapeutic techniques that disrupt, evade, or specifically target the pathogenic microenvironment have a high potential for improving therapeutic outcomes and should be considered a priority for immediate exploration. A schematic showing the various methods of extracellular matrix disruption/targeting in both fibrotic and cancerous environments. a Biomaterial-based cell therapy can be used to deliver anti-inflammatory cytokines, chemotherapeutics, or other factors for localized, slow release of therapeutics. b Mechanotherapeutics can be used to inhibit the deposition of molecules such as collagen that affect stiffness. c Ablation of the ECM and target tissue can be accomplished via mechanical degradation such as focused ultrasound. d Proteases can be used to improve the distribution of therapies such as oncolytic virus. e Localization of therapeutics such as checkpoint inhibitors can be improved with the targeting of specific ECM components, reducing off-target effects and toxicity.

Engineered Bifunctional Proteins for Targeted Cancer Therapy: Prospects and Challenges

Bifunctional proteins (BFPs) are a class of therapeutic agents produced through genetic engineering and protein engineering, and are increasingly used to treat various human diseases, including cancer. These proteins usually have two or more biological functions-specifically recognizing different molecular targets to regulate the related signaling pathways, or mediating effector molecules/cells to kill tumor cells. Unlike conventional small-molecule or single-target drugs, BFPs possess stronger biological activity but lower systemic toxicity. Hence, BFPs are considered to offer many benefits for the treatment of heterogeneous tumors. In this review, the authors briefly describe the unique structural feature of BFP molecules and innovatively divide them into bispecific antibodies, cytokine-based BFPs (immunocytokines), and protein toxin-based BFPs (immunotoxins) according to their mode of action. In addition, the latest advances in the development of BFPs are discussed and the potential limitations or problems in clinical applications are outlined. Taken together, future studies need to be centered on understanding the characteristics of BFPs for optimizing and designing more effective such drugs.

The JAK/STAT signaling pathway: from bench to clinic

The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway was discovered more than a quarter-century ago. As a fulcrum of many vital cellular processes, the JAK/STAT pathway constitutes a rapid membrane-to-nucleus signaling module and induces the expression of various critical mediators of cancer and inflammation. Growing evidence suggests that dysregulation of the JAK/STAT pathway is associated with various cancers and autoimmune diseases. In this review, we discuss the current knowledge about the composition, activation, and regulation of the JAK/STAT pathway. Moreover, we highlight the role of the JAK/STAT pathway and its inhibitors in various diseases.

The JAK/STAT signaling pathway: from bench to clinic

The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway was discovered more than a quarter-century ago. As a fulcrum of many vital cellular processes, the JAK/STAT pathway constitutes a rapid membrane-to-nucleus signaling module and induces the expression of various critical mediators of cancer and inflammation. Growing evidence suggests that dysregulation of the JAK/STAT pathway is associated with various cancers and autoimmune diseases. In this review, we discuss the current knowledge about the composition, activation, and regulation of the JAK/STAT pathway. Moreover, we highlight the role of the JAK/STAT pathway and its inhibitors in various diseases.

Viro-antibody therapy: engineering oncolytic viruses for genetic delivery of diverse antibody-based biotherapeutics

Cancer therapeutics approved for clinical application include oncolytic viruses and antibodies, which evolved by nature, but were improved by molecular engineering. Both facilitate outstanding tumor selectivity and pleiotropic activities, but also face challenges, such as tumor heterogeneity and limited tumor penetration. An innovative strategy to address these challenges combines both agents in a single, multitasking therapeutic, i.e., an oncolytic virus engineered to express therapeutic antibodies. Such viro-antibody therapies genetically deliver antibodies to tumors from amplified virus genomes, thereby complementing viral oncolysis with antibody-defined therapeutic action. Here, we review the strategies of viro-antibody therapy that have been pursued exploiting diverse virus platforms, antibody formats, and antibody-mediated modes of action. We provide a comprehensive overview of reported antibody-encoding oncolytic viruses and highlight the achievements of 13 years of viro-antibody research. It has been shown that functional therapeutic antibodies of different formats can be expressed in and released from cancer cells infected with different oncolytic viruses. Virus-encoded antibodies have implemented direct tumor cell killing, anti-angiogenesis, or activation of adaptive immune responses to kill tumor cells, tumor stroma cells or inhibitory immune cells. Importantly, numerous reports have shown therapeutic activity complementary to viral oncolysis for these modalities. Also, challenges for future research have been revealed. Established engineering technologies for both oncolytic viruses and antibodies will enable researchers to address these challenges, facilitating the development of effective viro-antibody therapeutics.

Local delivery strategies to restore immune homeostasis in the context of inflammation

Immune homeostasis is maintained by a precise balance between effector immune cells and regulatory immune cells. Chronic deviations from immune homeostasis, driven by a greater ratio of effector to regulatory cues, can promote the development and propagation of inflammatory diseases/conditions (i.e., autoimmune diseases, transplant rejection, etc.). Current methods to treat chronic inflammation rely upon systemic administration of non-specific small molecules, resulting in broad immunosuppression with unwanted side effects. Consequently, recent studies have developed more localized and specific immunomodulatory approaches to treat inflammation through the use of local biomaterial-based delivery systems. In particular, this review focuses on (1) local biomaterial-based delivery systems, (2) common materials used for polymeric-delivery systems and (3) emerging immunomodulatory trends used to treat inflammation with increased specificity.

Engineered antibody fusion proteins for targeted disease therapy

Since the FDA approval of the first therapeutic antibody 35 years ago, antibody-based products have gained prominence in the pharmaceutical market. Building on the early successes of monoclonal antibodies, more recent efforts have capitalized on the exquisite specificity and/or favorable pharmacokinetic properties of antibodies by developing fusion proteins that enable targeted delivery of therapeutic payloads which are otherwise ineffective when administered systemically. This review focuses on recent engineering and translational advances for therapeutics that genetically fuse antibodies to disease-relevant payloads, including cytokines, toxins, enzymes, neuroprotective agents, and soluble factor traps. With numerous antibody fusion proteins in the clinic and other innovative molecules poised to follow suit, these potent, multifunctional drug candidates promise to be a major player in the therapeutic development landscape for years to come.

The PD-1/PD-L1 Checkpoint in Normal Germinal Centers and Diffuse Large B-Cell Lymphomas

Besides a recognized role of PD-1/PD-L1 checkpoint in anti-tumour immune evasion, there is accumulating evidence that PD-1/PD-L1 interactions between B and T cells also play an important role in normal germinal center (GC) reactions. Even when smaller in number, T follicular helper cells (TFH) and regulatory T (TFR) or B (Breg) cells are involved in positive selection of GC B cells and may result critical in the lymphoma microenvironment. Here, we discuss a role of PD-1/PD-L1 during tumour evolution in diffuse large B cell lymphoma (DLBCL), a paradigm of GC-derived lymphomagenesis. We depict a progression model, in two phases, where malignant B cells take advantage of positive selection signals derived from correct antigen-presentation and PD-1/PD-L1 inter-cellular crosstalks to survive and initiate tumour expansion. Later, a constant pressure for the accumulation of genetic/epigenetic alterations facilitates that DLBCL cells exhibit higher PD-L1 levels and capacity to secrete IL-10, resembling Breg-like features. As a result, a complex immunosuppressive microenvironment is established where DLBCL cells sustain proliferation and survival by impairing regulatory control of TFR cells and limiting IL-21-mediated anti-tumour functions of TFH cells and maximize the use of PD-1/PD-L1 signaling to escape from CD8+ cytotoxic activity. Integration of these molecular and cellular addictions into a framework may contribute to the better understanding of the lymphoma microenvironment and contribute to the rationale for novel PD-1/PD-L1-based combinational immunotherapies in DLBCL.

Engineered Cytokines for Cancer and Autoimmune Disease Immunotherapy

Cytokine signaling is critical to a range of biological processes including cell development, tissue repair, aging, and immunity. In addition to acting as key signal mediators of the immune system, cytokines can also serve as potent immunotherapies with more than 20 recombinant products currently Food and Drug Administration (FDA)-approved to treat conditions including hepatitis, multiple sclerosis, arthritis, and various cancers. Yet despite their biological importance and clinical utility, cytokine immunotherapies suffer from intrinsic challenges that limit their therapeutic potential including poor circulation, systemic toxicity, and low tissue- or cell-specificity. In the past decade in particular, methods have been devised to engineer cytokines in order to overcome such challenges and here, the myriad strategies are reviewed that may be employed in order to improve the therapeutic potential of cytokine and chemokine immunotherapies with applications in cancer and autoimmune disease therapy, as well as tissue engineering and regenerative medicine. For clarity, these strategies are collected and presented as they vary across size scales, ranging from single amino acid substitutions, to larger protein-polymer conjugates, nano/micrometer-scale particles, and macroscale implants. Together, this work aims to provide readers with a timely view of the field of cytokine engineering with an emphasis on early-stage therapeutic approaches.

The immunocytokine L19-TNF eradicates sarcomas in combination with chemotherapy agents or with immune check-point inhibitors

Antibody-cytokine fusion proteins (also called 'immunocytokines') represent an emerging class of biopharmaceutical products, which are being considered for cancer immunotherapy. When used as single agents, pro-inflammatory immunocytokines are rarely capable of inducing complete and durable cancer regression in mouse models and in patients. However, the combination treatment with conventional chemotherapy or with other immune-stimulatory agents typically increases the therapeutic efficacy of immunocytokines. In this article, we describe combination treatments of a tumor-targeting antibody-cytokine fusion protein based on the L19 antibody (specific to a splice isoform of fibronectin) fused to murine tumor necrosis factor with standard chemotherapy (dacarbazine, trabectedin or melphalan) or with an immune check-point inhibitor (anti-PD-1) in a BALB/c derived immunocompetent murine model of sarcoma (WEHI-164). All combination treatments led to improved tumor remission compared to single-agent treatments, suggesting that these combination partners may be suitable for further clinical development in sarcoma patients.

Development of IL-15/IL-15Rα sushi domain-IgG4 Fc complexes in Pichia pastoris with potent activities and prolonged half-lives

BACKGROUND

Interleukin-15 (IL-15) is a critical cytokine for the development, proliferation, and function of natural killer (NK) cells, NKT cells, and CD8⁺ memory T cells and has become one of the most promising protein molecules for the treatment of cancer and viral diseases. However, there are several limitations in applying IL-15 in therapy, such as its low yield in vitro, limited potency, and short half-life in vivo. To date, there are several recombinant IL-15 agonists based on configurational modifications that are being pursued in the treatment of cancer, such as ALT-803, which are mainly produced from mammalian cells.

RESULTS

In this study, we designed two different forms of the IL-15 complex, which were formed by the noncovalent assembly of IL-15 with dimeric or monomeric sushi domain of IL-15 receptor α (SuIL-15Rα)-IgG4 Fc fusion protein and designated IL-15/SuIL-15Rα-dFc and IL-15/SuIL-15Rα-mFc, respectively. The two IL-15 complexes were expressed in Pichia pastoris (P. pastoris), and their activities and half-lives were evaluated and compared. Pharmacokinetic analysis showed that IL-15/SuIL-15Rα-dFc had a half-life of 14.26 h while IL-15/SuIL-15Rα-mFc had a half-life of 9.16 h in mice, which were much longer than the 0.7-h half-life of commercial recombinant human IL-15 (rhIL-15). Treatment of mice with intravenous injection of the two IL-15 complexes resulted in significant increases in NK cells, NKT cells, and memory CD8⁺ T cells, which were not observed after rhIL-15 treatment. Treatment of human peripheral blood mononuclear cells (PBMCs) from healthy donors with the two IL-15 complexes yielded enhanced NK and CD8⁺ T cell activation and proliferation, which was comparable to the effect of rhIL-15.

CONCLUSIONS

These findings indicate that the IL-15/SuIL-15Rα-dFc and IL-15/SuIL-15Rα-mFc produced in P. pastoris exhibit potent activities and prolonged half-lives and may serve as superagonists for immunotherapy in further research and applications.

Protein-Antibody Conjugates (PACs): A Plug-and-Play Strategy for Covalent Conjugation and Targeted Intracellular Delivery of Pristine Proteins

We report here on protein-antibody conjugates (PACs) that are used for antibody-directed delivery of protein therapeutics to specific cells. PACs have the potential to judiciously combine the merits of two prolific therapeutic approaches-biologics and antibody-drug conjugates. We utilize spherical polymer brushes to construct PACs using the combination of two simple and efficient functionally orthogonal click chemistries. In addition to the synthesis and characterization of these nanoparticles, we demonstrate that PACs are indeed capable of specifically targeting cells based on the presence of target antigen on the cell surface to deliver proteins. The potentially broad adaptability of PACs opens up new opportunities for targeted biologics in therapeutics and sensing.

A bispecific antibody agonist of the IL-2 heterodimeric receptor preferentially promotes in vivo expansion of CD8 and NK cells

The use of recombinant interleukin-2 (IL-2) as a therapeutic protein has been limited by significant toxicities despite its demonstrated ability to induce durable tumor-regression in cancer patients. The adverse events and limited efficacy of IL-2 treatment are due to the preferential binding of IL-2 to cells that express the high-affinity, trimeric receptor, IL-2Rαβγ such as endothelial cells and T-regulatory cells, respectively. Here, we describe a novel bispecific heavy-chain only antibody which binds to and activates signaling through the heterodimeric IL-2Rβγ receptor complex that is expressed on resting T-cells and NK cells. By avoiding binding to IL-2Rα, this molecule circumvents the preferential T-reg activation of native IL-2, while maintaining the robust stimulatory effects on T-cells and NK-cells in vitro. In vivo studies in both mice and cynomolgus monkeys confirm the molecule's in vivo biological activity, extended pharmacodynamics due to the Fc portion of the molecule, and enhanced safety profile. Together, these results demonstrate that the bispecific antibody is a safe and effective IL-2R agonist that harnesses the benefits of the IL-2 signaling pathway as a potential anti-cancer therapy.

Potential application of immunotherapy for modulation of pulp inflammation: opportunities for vital pulp treatment

Caries results in the demineralization and destruction of enamel and dentine, and as the disease progresses, irreversible pulpitis can occur. Vital pulp therapy (VPT) is directed towards pulp preservation and the prevention of the progression of inflammation. The outcomes of VPT are not always predictable, and there is often a poor correlation between clinical signs and symptoms, and the events occurring at a molecular level. The inflamed pulp expresses increased levels of cytokines, including tumour necrosis factor (TNF)-α, interleukin (IL)-1α, IL-1β, IL-4, IL-6, IL-8, IL-17 and IL-23, which recruit and drive a complex cellular immune response. Chronic inflammation and sustained cytokine release can result in irreversible pulp damage and a decreased capacity for tissue healing. Other chronic inflammatory diseases, such as psoriasis, inflammatory bowel diseases and rheumatoid arthritis, are also characterized by an dysregulated immune response composed of relatively high cytokine levels and increased numbers of immune cells along with microbial and hard-soft tissue destructive pathologies. Whilst anti-cytokine therapies have been successfully applied in the treatment of these diseases, this approach is yet to be attempted in cases of pulp inflammation. This review therefore focuses on the similarities in the aetiology between chronic inflammatory diseases and pulpitis, and explores how anti-cytokine therapies could be applied to manage an inflamed pulp and facilitate healing. Further proof-of-concept studies and clinical trials are justified to determine the effectiveness of these treatments to enable more predictable outcomes in VPT.

Dose escalation and expansion phase I studies with the tumour-targeting antibody-tumour necrosis factor fusion protein L19TNF plus doxorubicin in patients with advanced tumours, including sarcomas

BACKGROUND

L19TNF is a recombinant fusion protein composed of a human antibody fragment and human tumour necrosis factor. L19TNF targets the EDB domain of oncofetal fibronectin highly expressed in tumour vasculature and induces tumour remission in mouse tumours. We summarise two phase I trials testing a combination of L19TNF with doxorubicin in patients with solid tumours, particularly soft tissue sarcomas (STS).

PATIENTS AND METHODS

The first study, an open-label, dose-escalation and expansion phase I study of L19TNF plus doxorubicin, enrolled 27 patients. Three cohorts (10.4-17 μg/kg L19TNF) of patients received L19TNF intravenously at days 1, 3, and 5 and doxorubicin (75 mg/m², then 60 mg/m²) on day 1 every 3 weeks. The expansion cohort enrolled patients with STS. The second study tried to re-escalate the doxorubicin dose to 75 mg/m² with 13 μg/kg L19TNF. Among primary objectives was the establishment of a recommended dose (RD).

RESULTS

The combination was safely applicable. Dose-limiting toxicity occurred either at 17 μg/kg L19TNF or at 75 mg/m² doxorubicin. RD is 13 μg/kg L19TNF plus 60 mg/m² doxorubicin. In 15 STS patients of the extension cohort evaluable for efficacy, antitumour activity was observed with complete remission in 1, partial remission in 1 and minor tumour shrinkage in 7 patients. The median overall survival for this heavily pretreated cohort was 14.9 months.

CONCLUSION

L19TNF can be safely applied in combination with doxorubicin and induces encouraging tumour remissions in patients with soft tissue sarcomas.

ST36 Acupuncture Alleviates the Inflammation of Adjuvant-Induced Arthritic Rats by Targeting Monocyte/Macrophage Modulation

Background

Rheumatoid arthritis (RA) is a chronic systemic chronic autoimmune disease characterized by the aggregation of immune cells and secretion of cytokines in the joint synovium, causing hyperblastosis and even bone destruction. Acupuncture has been proven effective in RA treatment. This study aimed to investigate the anti-inflammatory action of acupuncture, specifically, in relation to immune cell interactions and key mediators.

Methods

Rats with adjuvant-induced arthritics (AIA) were treated with manual acupuncture (MA) at Zusanli (ST36). Joint edema and paw withdrawal latency were monitored to observe the effects on inflammation. The levels of 24 cytokines, chemokines, and growth factors in ankle joints during the treatment (on days 1, 7, 15, and 21) were detected by multiplex immunoassay. A bioinformatics analysis based on a directed weighted mathematical model was used to construct cell communication network diagrams and identify the key cells through calculation. The monocyte/macrophage polarization in inflamed joints was investigated by detecting M1- and M2-phenotypic populations and their related cytokines.

Results

ST36 MA alleviated paw edema and upregulated the nociceptive threshold of AIA rats. Several innate and adaptive immune cytokines were dynamically regulated by MA, and MA-treated rats showed a significant improvement in symptoms compared with AIA rats by day 21. The immune cell-cell communication networks were intensified with the development of RA but were significantly reduced after treatment with MA. MA was found to specifically regulate monocytes/macrophages in inflamed ankle joints ST36 MA also inhibited M1-phenotype macrophages accompanied by decreased levels of IL-1β.

Conclusions

ST36 MA showed anti-inflammatory and analgesic effects as well as inhibition of immune cell communication networks in inflamed joints of AIA rats. Inhibiting the polarization of macrophages to the M1-phenotype in inflamed joints may be one of the key mechanisms of MA anti-inflammatory action. This research highlighted a systematic research paradigm for investigating mechanisms of acupuncture action.

Inference of molecular structure for characterization and improvement of clinical grade immunocytokines

The use of immunomodulatory agents for the treatment of cancer is gaining a growing biopharmaceutical interest. Antibody-cytokine fusion proteins, namely immunocytokines, represent a promising solution for the regulation of the immune system at the site of disease. The three-dimensional arrangement of these molecules can profoundly influence their biological activity and pharmacokinetic properties. Structural techniques might provide important insight in the 3D arrangement of immunocytokines. Here, we performed structure investigations on clinical grade fusion proteins L19-IL2, IL12-L19L19 and L19L19-IL2 to elucidate their quaternary organization. Crystallographic characterization of the common L19 antibody fragment at a resolution of 2.0-Å was combined with low-resolution studies of the full-length chimeric molecules using small-angle synchrotron X-ray scattering (SAXS) and negative stain electron microscopy. Characterization of the full-length quaternary structures of the immunocytokines in solution by SAXS consistently supported the diabody structure in the L19-IL2 immunocytokine and allowed generation of low-resolution models of the chimeric proteins L19L19-IL2 and IL12-L19L19. Comparison with 3D reconstructions obtained from negative-stain electron microscopy revealed marked flexibility associated to the linker regions connecting the cytokine and the antibody components of the chimeric proteins. Collectively, our results indicate that low-resolution molecular structure characterizations provide useful complementary insights for the quality control of immunocytokines, constituting a powerful tool to guide the design and the subsequent optimization steps towards clinical enhancement of these chimeric protein reagents.

Current Trends in Cancer Immunotherapy

The search for an effective drug to treat oncological diseases, which have become the main scourge of mankind, has generated a lot of methods for studying this affliction. It has also become a serious challenge for scientists and clinicians who have needed to invent new ways of overcoming the problems encountered during treatments, and have also made important discoveries pertaining to fundamental issues relating to the emergence and development of malignant neoplasms. Understanding the basics of the human immune system interactions with tumor cells has enabled new cancer immunotherapy strategies. The initial successes observed in immunotherapy led to new methods of treating cancer and attracted the attention of the scientific and clinical communities due to the prospects of these methods. Nevertheless, there are still many problems that prevent immunotherapy from calling itself an effective drug in the fight against malignant neoplasms. This review examines the current state of affairs for each immunotherapy method, the effectiveness of the strategies under study, as well as possible ways to overcome the problems that have arisen and increase their therapeutic potentials.

An engineered 4-1BBL fusion protein with "activity on demand"

Engineered cytokines are gaining importance in cancer therapy, but these products are often limited by toxicity, especially at early time points after intravenous administration. 4-1BB is a member of the tumor necrosis factor receptor superfamily, which has been considered as a target for therapeutic strategies with agonistic antibodies or using its cognate cytokine ligand, 4-1BBL. Here we describe the engineering of an antibody fusion protein, termed F8-4-1BBL, that does not exhibit cytokine activity in solution but regains biological activity on antigen binding. F8-4-1BBL bound specifically to its cognate antigen, the alternatively spliced EDA domain of fibronectin, and selectively localized to tumors in vivo, as evidenced by quantitative biodistribution experiments. The product promoted a potent antitumor activity in various mouse models of cancer without apparent toxicity at the doses used. F8-4-1BBL represents a prototype for antibody-cytokine fusion proteins, which conditionally display "activity on demand" properties at the site of disease on antigen binding and reduce toxicity to normal tissues.

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.

Sortase-Mediated Site-Specific Modification of Interleukin-2 for the Generation of a Tumor-Targeting Acetazolamide-Cytokine Conjugate

Small ligands specific to tumor-associated antigens can be used as alternatives to antibodies for the delivery of small payloads such as radionuclides, cytotoxic drugs, and fluorophores. Their use as a delivery moiety of bioactive proteins such as cytokines remains largely unexplored. Here, we describe the preparation and in vivo characterization of the first small molecule-cytokine conjugate targeting carbonic anhydrase IX (CAIX), a marker of renal cell carcinoma and hypoxia. Site-specific conjugation between interleukin-2 and acetazolamide was obtained by sortase A-mediated transpeptidation. Binding of the conjugate to the cognate CAIX antigen was confirmed by surface plasmon resonance. The in vivo targeting of structures expressing carbonic anhydrase IX was assessed by biodistribution experiments in tumor-bearing mice. Optimization of manufacturability and tumor-targeting performance of acetazolamide-cytokine products will be required in order to enable industrial applications.

Phage Display Derived Monoclonal Antibodies: From Bench to Bedside

Monoclonal antibodies (mAbs) have become one of the most important classes of biopharmaceutical products, and they continue to dominate the universe of biopharmaceutical markets in terms of approval and sales. They are the most profitable single product class, where they represent six of the top ten selling drugs. At the beginning of the 1990s, an in vitro antibody selection technology known as antibody phage display was developed by John McCafferty and Sir. Gregory Winter that enabled the discovery of human antibodies for diverse applications, particularly antibody-based drugs. They created combinatorial antibody libraries on filamentous phage to be utilized for generating antigen specific antibodies in a matter of weeks. Since then, more than 70 phage–derived antibodies entered clinical studies and 14 of them have been approved. These antibodies are indicated for cancer, and non-cancer medical conditions, such as inflammatory, optical, infectious, or immunological diseases. This review will illustrate the utility of phage display as a powerful platform for therapeutic antibodies discovery and describe in detail all the approved mAbs derived from phage display.

Targeting the Tumor Microenvironment in Neuroblastoma: Recent Advances and Future Directions

Neuroblastoma (NB) is the most common pediatric tumor malignancy that originates from the neural crest and accounts for more than 15% of all the childhood deaths from cancer. The neuroblastoma cancer research has long been focused on the role of MYCN oncogene amplification and the contribution of other genetic alterations in the progression of this malignancy. However, it is now widely accepted that, not only tumor cells, but the components of tumor microenvironment (TME), including extracellular matrix, stromal cells and immune cells, also contribute to tumor progression in neuroblastoma. The complexity of different components of tumor stroma and their resemblance with surrounding normal tissues pose huge challenges for therapies targeting tumor microenvironment in NB. Hence, the detailed understanding of the composition of the TME of NB is crucial to improve existing and future potential immunotherapeutic approaches against this childhood cancer. In this review article, I will discuss different components of the TME of NB and the recent advances in the strategies, which are used to target the tumor microenvironment in neuroblastoma.