Active immunization with IL-1 displayed on virus-like particles protects from autoimmune arthritis

Enhancing Protective Antibodies against Opioids through Antigen Display on Virus-like Particles

Opioid use disorder (OUD) has become a public health crisis, with recent significant increases in the number of deaths due to overdose. Vaccination can provide an attractive complementary strategy to combat OUD. A key for high vaccine efficacy is the induction of high levels of antibodies specific to the drug of abuse. Herein, a powerful immunogenic carrier, virus-like particle mutant bacteriophage Qβ (mQβ), has been investigated as a carrier of a small molecule hapten 6-AmHap mimicking heroin. The mQβ-6-AmHap conjugate was able to induce significantly higher levels of IgG antibodies against 6-AmHap than mice immunized with the corresponding tetanus toxoid-6-AmHap conjugate in head-to-head comparison studies in multiple strains of mice. The IgG antibody responses were persistent with high anti-6-AmHap titers 600 days after being immunized with mQβ-6-AmHap. The antibodies induced exhibited strong binding toward multiple heroin/morphine derivatives that have the potential to be abused, while binding weakly to medications used for OUD treatment and pain relief. Furthermore, vaccination effectively reduced the impacts of morphine on mice in both ambulation and antinociception assays, highlighting the translational potential of the mQβ-6-AmHap conjugate to mitigate the harmful effects of drugs of abuse.

Bacteriophage Virus-Like Particles: Platforms for Vaccine Design

Virus-like particles (VLPs) derived from bacteriophages have many applications in biomedical sciences, especially in the development of candidate vaccines against viral and bacterial infections. Bacteriophage VLPs can be manufactured cheaply and in large quantities in bacteria compared to eukaryotic expression systems. In addition to this, bacteriophage VLPs are excellent platforms for vaccine design for the following reason: Humans do not have preexisting antibodies against bacteriophage VLPs. Thus, antigens displayed on bacteriophage VLP platforms are expected to be highly immunogenic. As such, VLPs derived from MS2, PP7, Qβ, AP205, P22 bacteriophages, etc. have been used to develop candidate vaccines against human infectious and noninfectious agents. This mini-review summarizes data from some of the candidate bacteriophage-based VLP peptide vaccines that have been developed. The review also highlights some strategies used to develop the candidate bacteriophage-based VLP peptide vaccines.

Epitope-Directed Antibody Elicitation by Genetically Encoded Chemical Cross-Linking Reactivity in the Antigen

No current methods can selectively elicit an antibody response to a specific conformational epitope in a whole antigen in vivo. Here, we incorporated Nε-acryloyl-l-lysine (AcrK) or Nε-crotonyl-l-lysine (Kcr) with cross-linking activities into the specific epitopes of antigens and immunized mice to generate antibodies that can covalently cross-link with the antigens. By taking advantage of antibody clonal selection and evolution in vivo, an orthogonal antibody-antigen cross-linking reaction can be generated. With this mechanism, we developed a new approach for facile elicitation of antibodies binding to specific epitopes of the antigen in vivo. Antibody responses were directed and enriched to the target epitopes on protein antigens or peptide-KLH conjugates after mouse immunization with the AcrK or Kcr-incorporated immunogens. The effect is so prominent that the majority of selected hits bind to the target epitope. Furthermore, the epitope-specific antibodies effectively block IL-1β from activating its receptor, indicating its potential for the development of protein subunit vaccines.

Virus-inspired strategies for cancer therapy

The intentional use of viruses for cancer therapy dates back over a century. As viruses are inherently immunogenic and naturally optimized delivery vehicles, repurposing viruses for drug delivery, tumor antigen presentation, or selective replication in cancer cells represents a simple and elegant approach to cancer treatment. While early virotherapy was fraught with harsh side effects and low response rates, virus-based therapies have recently seen a resurgence due to newfound abilities to engineer and tune oncolytic viruses, virus-like particles, and virus-mimicking nanoparticles for improved safety and efficacy. However, despite their great potential, very few virus-based therapies have made it through clinical trials. In this review, we present an overview of virus-inspired approaches for cancer therapy, discuss engineering strategies to enhance their mechanisms of action, and highlight their application for overcoming the challenges of traditional cancer therapies.

Preclinical Efficacy of a Capsid Virus-like Particle-Based Vaccine Targeting IL-1β for Treatment of Allergic Contact Dermatitis

Hypersensitivity to a contact allergen is one of the most abundant forms of inflammatory skin disease. Today, more than 20% of the general population are sensitized to one or more contact allergens, making this disease an important healthcare issue, as re-exposure to the allergen can initiate the clinical disease termed allergic contact dermatitis (ACD). The current standard treatment using corticosteroids is effective, but it has side effects when used for longer periods. Therefore, there is a need for new alternative therapies for severe ACD. In this study, we used the versatile Tag/Catcher AP205 capsid virus-like particle (cVLP) vaccine platform to develop an IL-1β-targeted vaccine and to assess the immunogenicity and in vivo efficacy of the vaccine in a translational mouse model of ACD. We show that vaccination with cVLPs displaying full-length murine IL-1β elicits high titers of neutralizing antibodies, leading to a significant reduction in local IL-1β levels as well as clinical symptoms induced by treatment with 1-Fluoro-2,4-dinitrobenzene (DNFB). Moreover, we show that a single amino acid mutation in muIL-1β reduces the biological activity while maintaining the ability to induce neutralizing antibodies. Collectively, the data suggest that a cVLP-based vaccine displaying full-length IL-1β represents a promising vaccine candidate for use as an alternative treatment modality against severe ACD.

A VLP-based vaccine targeting ANGPTL3 lowers plasma triglycerides in mice

Elevated triglycerides (TGs) are an important risk factor for the development of coronary heart disease (CHD) and in acute pancreatitis. Angiopoietin-like proteins 3 (ANGPTL3) and 4 (ANGPTL4) are critical regulators of TG metabolism that function by inhibiting the activity of lipoprotein lipase (LPL), which is responsible for hydrolyzing triglycerides in lipoproteins into free fatty acids. Interestingly, individuals with loss-of-function mutations in ANGPTL3 and ANGPTL4 have low plasma TG levels, have a reduced risk of CHD, and are otherwise healthy. Consequently, interventions targeting ANGPTL3 and ANGPTL4 have emerged as promising new approaches for reducing elevated TGs. Here, we developed virus-like particle (VLP) based vaccines that target the LPL binding domains of ANGPTL3 and ANGPTL4. ANGPTL3 VLPs and ANGPTL4 VLPs are highly immunogenic in mice and vaccination with ANGPTL3 VLPs, but not ANGPTL4 VLPs, was associated with reduced steady state levels of TGs. Immunization with ANGPTL3 VLPs rapidly cleared circulating TG levels following an oil gavage challenge and enhanced plasma LPL activity. These data indicate that targeting ANGPTL3 by active vaccination is a potential alternative to other ANGPTL3-inhibiting therapies.

Targeting IL-1β in the Treatment of Atherosclerosis

The role of inflammation in atherosclerosis has been recognized several decades ago and existing treatments provide benefits in part through non-specific anti-inflammatory actions. Compared with other cytokines, interleukin-1β (IL-1β) is associated with acute and chronic inflammation. Anti-inflammatory therapy with canakinumab targeting the IL-1β innate immunity pathway could significantly reduce the rate of recurrent cardiovascular events than placebo. The results of CANTOS suggested an important role of IL-1β in atherosclerosis. However, there are numerous mechanisms that are to be clarified. We herein discussed the important immunomodulatory effect IL-1β exerts on atherosclerosis and the potential mechanisms underlying it. We also reviewed bench-to-bedside clinical translation of IL-1β neutralizing strategies associated with the use of IL-1β blockade in patients with atherosclerosis.

Genetic engineering strategies for construction of multivalent chimeric VLPs vaccines

Introduction: Over the past two decades, virus-like particles (VLPs) have been developed as a new generation of vaccines against viral infections. Based on VLPs, chimeric VLPs (chi-VLPs) have been generated through genetic modifications or chemical couplings. For construction of multivalent chi-VLPs vaccines, multiple genetic engineering strategies are continuously being developed. Thus, it is important to provide a summary as reference for researchers in this field.Areas covered: The representative studies on the genetic engineered multivalent chi-VLPs are summarized and mainly focused on chimeric capsid VLPs and chimeric enveloped VLPs. The advantages and limitations of each strategy are also discussed at last, as well as opinions on platform choice and future directions of eVLPs vaccines.Expert opinion: The design of multivalent chi-VLPs vaccines needs to meet the following specifications: 1) the incorporated antigens are suggested to display on the exposed surface of chi-VLPs and do not have excessive adverse effects on the stability of chi-VLPs; 2) the chi-VLPs should elicit protective antibodies against the incorporated antigen as well as the source virus of VLPs. However, there is no requirement of retaining the antigenicity of VLPs when using VLPs solely as carriers for antigens display or drug delivery.

Vaccination against Allergy: A Paradigm Shift?

Since the discovery that IgE antibodies mediate allergy, decades of research have unraveled complex mechanisms associated with conventional immunotherapy and the vital protagonists that shape 'immune tolerance' to allergens. Debate exists on what should constitute the dominant effector mechanism in driving rational drug designs for next-generation immunotherapies. As vaccine technology continues to advance, the development of novel vaccines in this area of continued medical need might stand on a threshold of breakthrough inspired by experiments by Dunbar on the passive vaccination of allergic animals more than 100 years ago. In this opinion article, we discuss both novel insights into IgG antibodies as the principle effector modality induced by specific immunotherapy and advances in antigen-carrier design that may catapult allergy treatment into our modern world.

Advantages and Prospects of Tag/Catcher Mediated Antigen Display on Capsid-Like Particle-Based Vaccines

Capsid-like particles (CLPs) are multimeric, repetitive assemblies of recombinant viral capsid proteins, which are highly immunogenic due to their structural similarity to wild-type viruses. CLPs can be used as molecular scaffolds to enable the presentation of soluble vaccine antigens in a similar structural format, which can significantly increase the immunogenicity of the antigen. CLP-based antigen display can be obtained by various genetic and modular conjugation methods. However, these vary in their versatility as well as efficiency in achieving an immunogenic antigen display. Here, we make a comparative review of the major CLP-based antigen display technologies. The Tag/Catcher-AP205 platform is highlighted as a particularly versatile and efficient technology that offers new qualitative and practical advantages in designing modular CLP vaccines. Finally, we discuss how split-protein Tag/Catcher conjugation systems can help to further propagate and enhance modular CLP vaccine designs.

PTPN2 Regulates Inflammasome Activation and Controls Onset of Intestinal Inflammation and Colon Cancer

Variants in the gene locus encoding protein tyrosine phosphatase non-receptor type 2 (PTPN2) are associated with inflammatory disorders, including inflammatory bowel diseases, rheumatoid arthritis, and type 1 diabetes. The anti-inflammatory role of PTPN2 is highlighted by the fact that PTPN2-deficient mice die a few weeks after birth because of systemic inflammation and severe colitis. However, the tissues, cells, and molecular mechanisms that contribute to this phenotype remain unclear. Here, we demonstrate that myeloid cell-specific deletion of PTPN2 in mice (PTPN2-LysMCre) promotes intestinal inflammation but protects from colitis-associated tumor formation in an IL-1β-dependent manner. Elevated levels of mature IL-1β production in PTPN2-LysMCre mice are a consequence of increased inflammasome assembly due to elevated phosphorylation of the inflammasome adaptor molecule ASC. Thus, we have identified a dual role for myeloid PTPN2 in directly regulating inflammasome activation and IL-1β production to suppress pro-inflammatory responses during colitis but promote intestinal tumor development.

Biodegradable Viral Nanoparticle/Polymer Implants Prepared via Melt-Processing

Viral nanoparticles have been utilized as a platform for vaccine development and are a versatile system for the display of antigenic epitopes for a variety of disease states. However, the induction of a clinically relevant immune response often requires multiple injections over an extended period of time, limiting patient compliance. Polymeric systems to deliver proteinaceous materials have been extensively researched to provide sustained release, which would limit administration to a single dose. Melt-processing is an emerging manufacturing method that has been utilized to create polymeric materials laden with proteins as an alternative to typical solvent-based production methods. Melt-processing is advantageous because it is continuous, solvent-free, and 100% of the therapeutic protein is encapsulated. In this study, we utilized melt-encapsulation to fabricate viral nanoparticle laden polymeric materials that effectively deliver intact particles and generate carrier specific antibodies in vivo. The effects of initial processing and postprocessing on particle integrity and aggregation were studied to develop processing windows for scale-up and the creation of more complex materials. The dispersion of particles within the PLGA matrix was studied, and the effect of additives and loading level on the release profile was determined. Overall, melt-encapsulation was found to be an effective method to produce composite materials that can deliver viral nanoparticles over an extended period and elicit an immune response comparable to typical administration schedules.

Milling solid proteins to enhance activity after melt-encapsulation

Polymeric systems for the immobilization and delivery of proteins have been extensively used for therapeutic and catalytic applications. While most devices have been created via solution based methods, hot melt extrusion (HME) has emerged as an alternative due to the high encapsulation efficiencies and solvent-free nature of the process. HME requires high temperatures and mechanical stresses that can result in protein aggregation and denaturation, but additives and chemical modifications have been explored to mitigate these effects. This study explores the use of solid-state ball milling to decrease protein particle size before encapsulation within poly(lactic-co-glycolic acid) (PLGA) via HME. The impact of milling on particle dispersion, retained enzymatic activity, secondary structure stability, and release was explored for lysozyme, glucose oxidase, and the virus-like particle derived from Qβ to fully understand the impact of milling on protein systems with different sizes and complexities. The results of this study describe the utility of milling to further increase the stability of protein/polymer systems prepared via HME.

Biomaterial strategies for generating therapeutic immune responses

Biomaterials employed to raise therapeutic immune responses have become a complex and active field. Historically, vaccines have been developed primarily to fight infectious diseases, but recent years have seen the development of immunologically active biomaterials towards an expanding list of non-infectious diseases and conditions including inflammation, autoimmunity, wounds, cancer, and others. This review structures its discussion of these approaches around a progression from single-target strategies to those that engage increasingly complex and multifactorial immune responses. First, the targeting of specific individual cytokines is discussed, both in terms of delivering the cytokines or blocking agents, and in terms of active immunotherapies that raise neutralizing immune responses against such single cytokine targets. Next, non-biological complex drugs such as randomized polyamino acid copolymers are discussed in terms of their ability to raise multiple different therapeutic immune responses, particularly in the context of autoimmunity. Last, biologically derived matrices and materials are discussed in terms of their ability to raise complex immune responses in the context of tissue repair. Collectively, these examples reflect the tremendous diversity of existing approaches and the breadth of opportunities that remain for generating therapeutic immune responses using biomaterials.

Polymer Structure and Conformation Alter the Antigenicity of Virus-like Particle-Polymer Conjugates

Covalent conjugation of water-soluble polymers to proteins is critical for evading immune surveillance in the field of biopharmaceuticals. The most common and long-standing polymer modification is the attachment of methoxypoly(ethylene glycol) (mPEG), termed PEGylation, which has led to several clinically approved pharmaceuticals. Recent data indicate that brush-type polymers significantly enhance in vitro and in vivo properties. Herein, the polymer conformation of poly(ethylene glycol) is detailed and compared with those of water-soluble polyacrylate and polynorbornene (PNB) when attached to icosahedral virus-like particles. Small-angle neutron scattering reveals vastly different polymer conformations of the multivalent conjugates. Immune recognition of conjugated particles was evaluated versus PEGylated particles, and PNB conjugation demonstrated the most effective shielding from antibody recognition.

Symmetry-Directed Design of Protein Cages and Protein Lattices and Their Applications

The assembly of individual protein subunits into large-scale structures is important in many biological contexts. Proteins may assemble into geometrical cages or extended lattices that are characterized by a high degree of symmetry; examples include viral capsids and bacterial S-layers. The precisely defined higher order structure exhibited by these assemblies has inspired efforts to design such structures de novo by applying the principles of symmetry evident in natural protein assemblies. Here we discuss progress towards this goal and also examples of natural protein cages and lattices that have been engineered to repurpose them towards a diverse range of applications in materials science and nano-medicine.

Viruses and Virus-Like Particles in Biotechnology: Fundamentals and Applications

Although viruses are simple biological systems, they are capable of evolving highly efficient techniques for infecting cells, expressing their genomes, and generating new copies of themselves. It is possible to genetically manipulate most of the different classes of known viruses in order to produce recombinant viruses that express foreign proteins. Recombinant viruses have been used in gene therapy to deliver selected genes into higher organisms, in vaccinology and immunotherapy, and as important research tools to study the structure and function of these proteins.

Virus-like particles (VLPs) are multiprotein structures that mimic the organization and conformation of authentic native viruses but lack the viral genome. They have been applied not only as prophylactic and therapeutic vaccines but also as vehicles in drug and gene delivery and, more recently, as tools in nanobiotechnology.

In this chapter, basic and advanced features of viruses and VLPs are presented and their major applications are discussed. The different production platforms based on animal cell technology are explained, and their main challenges and future perspectives are explored. The implications of large-scale production of viruses and VLPs are discussed in the context of process control, monitoring, and optimization. The main upstream and downstream technical challenges are identified and discussed accordingly.

Active immunization with human interleukin-15 induces neutralizing antibodies in non-human primates

Background

Interleukin-15 is an immunostimulatory cytokine overexpressed in several autoimmune and inflammatory diseases such as Rheumatoid Arthritis, psoriasis and ulcerative colitis; thus, inhibition of IL-15-induced signaling could be clinically beneficial in these disorders. Our approach to neutralize IL-15 consisted in active immunization with structurally modified human IL-15 (mhIL-15) with the aim to induce neutralizing antibodies against native IL-15. In the present study, we characterized the antibody response in Macaca fascicularis, non-human primates that were immunized with a vaccine candidate containing mhIL-15 in Aluminum hydroxide (Alum), Montanide and Incomplete Freund’s Adjuvant.

Results

Immunization with mhIL-15 elicited a specific antibodies response that neutralized native IL-15-dependent biologic activity in a CTLL-2 cell proliferation assay. The highest neutralizing response was obtained in macaques immunized with mhIL-15 adjuvanted in Alum. This response, which was shown to be transient, also inhibited the activity of simian IL-15 and did not affect the human IL-2-induced proliferation of CTLL-2 cells. Also, in a pool of synovial fluid cells from two Rheumatoid Arthritis patients, the immune sera slightly inhibited TNF-α secretion. Finally, it was observed that this vaccine candidate neither affect animal behavior, clinical status, blood biochemistry nor the percentage of IL-15-dependent cell populations, specifically CD56⁺ NK and CD8⁺ T cells.

Conclusion

Our results indicate that vaccination with mhIL-15 induced neutralizing antibodies to native IL-15 in non-human primates. Based on this fact, we propose that this vaccine candidate could be potentially beneficial for treatment of diseases where IL-15 overexpression is associated with their pathogenesis.

Virus-based nanoparticles as platform technologies for modern vaccines

Nanoscale engineering is revolutionizing the development of vaccines and immunotherapies. Viruses have played a key role in this field because they can function as prefabricated nanoscaffolds with unique properties that are easy to modify. Viruses are immunogenic via multiple pathways, and antigens displayed naturally or by engineering on the surface can be used to create vaccines against the cognate virus, other pathogens, specific molecules or cellular targets such as tumors. This review focuses on the development of virus-based nanoparticle systems as vaccines indicated for the prevention or treatment of infectious diseases, chronic diseases, cancer, and addiction. WIREs Nanomed Nanobiotechnol 2016, 8:554-578. doi: 10.1002/wnan.1383 For further resources related to this article, please visit the WIREs website.

A Modular Vaccine Development Platform Based on Sortase-Mediated Site-Specific Tagging of Antigens onto Virus-Like Particles

Virus-like particles (VLPs) can be used as powerful nanoscale weapons to fight against virus infection. In addition to direct use as vaccines, VLPs have been extensively exploited as platforms on which to display foreign antigens for prophylactic vaccination and immunotherapeutic treatment. Unfortunately, fabrication of new chimeric VLP vaccines in a versatile, site-specific and highly efficient manner is beyond the capability of traditional VLP vaccine design approaches, genetic insertion and chemical conjugation. In this study, we described a greatly improved VLP display strategy by chemoenzymatic site-specific tailoring antigens on VLPs surface with high efficiency. Through the transpeptidation mediated by sortase A, one protein and two epitopes containing N-terminal oligoglycine were conjugated to the LPET motif on the surface of hepatitis B virus core protein (HBc) VLPs with high density. All of the new chimeric VLPs induced strong specific IgG responses. Furthermore, the chimeric VLPs with sortase A tagged enterovirus 71 (EV71) SP70 epitope could elicit effective antibodies against EV71 lethal challenging as well as the genetic insertion chimeric VLPs. The sortase A mediated chemoenzymatic site-specific tailoring of the HBc VLP approach shows great potential in new VLP vaccine design for its simplicity, site specificity, high efficiency, and versatility.

SplitCore Technology Allows Efficient Production of Virus-Like Particles Presenting a Receptor-Contacting Epitope of Human IgE

Immunoglobulin E (IgE) plays a central role in type I hypersensitivity including allergy and asthma. Novel treatment strategy envisages development of a therapeutic vaccine designed to elicit autologous blocking antibodies against the IgE. We sought to develop an IgE-epitope antigen that induces antibodies against a receptor-contacting epitope on human IgE molecule. We designed the VLP immunogens which utilize hepatitis B virus core protein (HBcAg) as a carrier, and present arrays of the receptor-contacting epitopes of the human IgE on their surfaces. FG loop from the IgE domain Cε3 was engineered into the HBcAg. Two constructs explore a well-established approach of insertion into a main immunodominant region of the HBcAg. Third construct is different in that the carrier is produced in a form of an assembly of two polypeptide chains which upon expression remain associated in a stable VLP-forming subunit (SplitCore technology). No VLPs were isolated from E.coli expressing the IgE-epitope antigens with contiguous sequences. On the contrary, the SplitCore antigen carrying the FG loop efficiently formed the VLPs. Immunization of mice with the VLPs presenting receptor-contacting epitope of the IgE elicited antibodies recognizing the human IgE in ELISA.

Beyond passive immunization: toward a nanoparticle-based IL-17 vaccine as first in class of future immune treatments

Nanoparticles occur naturally as part of repetitive molecular structures forming virus-like particles (VLPs). VLPs are powerful immune activators. Specifically, VLP can elicit a direct activation of B lymphocytes to trigger production of antibodies targeted at molecules chemically linked to the VLP. We here review recent data from genetics research, large-scale genomic sequencing, as well as clinical trials which suggest that a VLP-based vaccine against the signaling molecule IL-17 will be safe and effective in the common skin disease psoriasis, as well as other conditions. Active vaccination against IL-17 is capable of replacing the costly manufacture of antibodies currently in clinical use with huge implications for treatment availability and health economics.

Immunization against an IL-6 peptide induces anti-IL-6 antibodies and modulates the Delayed-Type Hypersensitivity reaction in cynomolgus monkeys

Interleukin-6 (IL-6) overproduction has been involved in the pathogenesis of several chronic inflammatory diseases and the administration of an anti-IL-6 receptor monoclonal antibody has been proven clinically efficient to treat them. However, the drawbacks of monoclonal antibodies have led our group to develop an innovative anti-IL-6 strategy using a peptide-based active immunization. This approach has previously shown its efficacy in a mouse model of systemic sclerosis. Here the safety, immunogenicity, and efficacy of this strategy was assessed in non human primates. No unscheduled death and clinical signs of toxicity was observed during the study. Furthermore, the cynomolgus monkeys immunized against the IL-6 peptide produced high levels of anti-IL-6 antibodies as well as neutralizing antibodies compared to control groups. They also showed an important decrease of the cumulative inflammatory score following a delayed-type hypersensitivity reaction induced by the Tetanus vaccine compared to control groups (minus 57,9%, P = 0.014). These findings are highly significant because the immunizing IL-6 peptide used in this study is identical in humans and in monkeys and this novel anti-IL-6 strategy could thus represent a promising alternative to monoclonal antibodies.

Development of an Interleukin-1β Vaccine in Patients with Type 2 Diabetes

Interleukin-1β (IL-1β) is a key cytokine involved in inflammatory illnesses including rare hereditary diseases and common chronic inflammatory conditions as gout, rheumatoid arthritis, and type 2 diabetes mellitus, suggesting reduction of IL-1β activity as new treatment strategy. The objective of our study was to assess safety, antibody response, and preliminary efficacy of a novel vaccine against IL-1β. The vaccine hIL1bQb consisting of full-length, recombinant IL-1β coupled to virus-like particles was tested in a preclinical and clinical, randomized, placebo-controlled, double-blind study in patients with type 2 diabetes. The preclinical simian study showed prompt induction of IL-1β-specific antibodies upon vaccination, while neutralizing antibodies appeared with delay. In the clinical study with 48 type 2 diabetic patients, neutralizing IL-1β-specific antibody responses were detectable after six injections with doses of 900 µg. The development of neutralizing antibodies was associated with higher number of study drug injections, lower baseline body mass index, improvement of glycemia, and C-reactive protein (CRP). The vaccine hIL1bQb was safe and well-tolerated with no differences regarding adverse events between patients receiving hIL1bQb compared to placebo. This is the first description of a vaccine against IL-1β and represents a new treatment option for IL-1β-dependent diseases such as type 2 diabetes mellitus (ClinicalTrials.gov NCT00924105).

The application of virus-like particles as vaccines and biological vehicles

Virus-like particles (VLPs) can be spontaneously self-assembled by viral structural proteins under appropriate conditions in vitro while excluding the genetic material and potential replication probability. In addition, VLPs possess several features including can be rapidly produced in large quantities through existing expression systems, highly resembling native viruses in terms of conformation and appearance, and displaying repeated cluster of epitopes. Their capsids can be modified via genetic insertion or chemical conjugation which facilitating the multivalent display of a homologous or heterogeneous epitope antigen. Therefore, VLPs are considered as a safe and effective candidate of prophylactic and therapeutic vaccines. VLPs, with a diameter of approximately 20 to 150 nm, also have the characteristics of nanometer materials, such as large surface area, surface-accessible amino acids with reactive moieties (e.g., lysine and glutamic acid residues), inerratic spatial structure, and good biocompatibility. Therefore, assembled VLPs have great potential as a delivery system for specifically carrying a variety of materials. This review summarized recent researches on VLP development as vaccines and biological vehicles, which demonstrated the advantages and potential of VLPs in disease control and prevention and diagnosis. Then, the prospect of VLP biology application in the future is discussed as well.

Antigen delivery by virus-like particles for immunotherapeutic vaccination

Virus-like particles (VLPs) are an effective means of establishing both prophylactic and therapeutic immunity against their source virus or heterologous antigens. The particulate nature and repetitive structure of VLPs makes them ideal for stimulating potent immune responses. Epitopes delivered by VLPs can be presented on MHC-II for stimulation of a humoral immune response, or cross-presented onto MHC-I leading to cell-mediated immunity. VLPs as particulate subunit vaccine carriers are showing promise in preclinical and clinical trials for the treatment of many conditions including cancer, autoimmunity, allergies and addiction. Supporting the delivery of almost any form of antigenic material, VLPs are ideal candidate vectors for development of future vaccines.

A Targeted Multiple Antigenic Peptide Vaccine Augments the Immune Response to Self TGF-β1 and Suppresses Ongoing Hepatic Fibrosis

Transforming growth factor (TGF)-β1 expression is induced upon liver injury, and plays a critical role in hepatic fibrosis. Antibodies against TGF-β1 represent a novel approach in the treatment of hepatic fibrosis. However, TGF-β1 is not a suitable antigen due to immunological tolerance. In the current study, we synthesized a multiple antigenic peptide (MAP) vaccine against the dominant B-cell epitope of TGF-β1. The immunogenicity and potential therapeutic effects of this vaccine were examined using a rat model of hepatic fibrosis. Dominant B-cell epitopes of TGF-β1 were identified using bioinformatic program. An MAP vaccine corresponding to the 90-98 amino acid domain of TGF-β1 and containing four dendritic arms was synthesized using a 9-fluorenylmethoxycarbonyl solid phase method. Hepatic fibrosis which was induced in male Sprague-Dawley rats received a high-fat diet and ethanol (1.8 g/kg). Starting from the third week, rats were exposed to 40 % carbon tetrachloride (CCl4; 150 μl/100 g body weight twice weekly, initially 200 μl/100 g) treatment for a duration of 8 weeks. Rats received the MAP vaccine (100 μg) or Freund's adjuvant at weeks 1, 3, 5. A group of rats receiving the fibrosis-inducing regimen alone and a group of healthy rats (receiving an olive oil vehicle alone) were included as controls. At the conclusion of the experiment, serum titre of TGF-β1 antibody was measured using ELISA and a standard liver functional test panel was examined. The extent of hepatic fibrosis was determined by measuring hydroxyproline content in the liver as well as hematoxylin-eosin (HE) and van Gieson (VG) staining. The expression of TGF-β1 and alpha-smooth muscle actin (α-SMA) was examined using immunohistochemistry, and presented as positive staining cells. The MAP purity was >90 % upon reverse phase high-performance liquid chromatography, with apparent molecular weight at 4.77 kDa. Serum TGF-β1 antibody titre was 1:256. The fibrosis-inducing treatment produced significant liver damage, as reflected by increases in liver functional test, HE and VG staining. The MAP vaccine attenuated such damage, as reflected by decreased alanine aminotransferase, aspartate aminotransferase, total bilirubin, and hepatic hydroxyproline (116.78 ± 23.76 vs. 282.71 ± 136.94 IU/L; 319.78 ± 82.48 vs. 495.29 ± 137.13 IU/L; 2.02 ± 0.27 vs. 4.01 ± 0.52 μmol/L; 263.67 ± 41.18 vs. 439.14 ± 43.29 μg/g vs. in model rats, respectively; p < 0.01), as well as fibrosis extent by HE and VG staining. The MAP vaccine reduced TGF-β1 and α-SMA expression in rats (0.325 ± 0.059 vs. 0.507 ± 0.044 IOD/area; 0.318 ± 0.058 vs. 0.489 ± 0.029 IOD/area vs. model rats, respectively; p < 0.05). The TGF-β1 MAP vaccine could generate sufficient antibody that suppresses the development of hepatic fibrosis.

Plant virus particles carrying tumour antigen activate TLR7 and Induce high levels of protective antibody

Induction of potent antibody is the goal of many vaccines targeted against infections or cancer. Modern vaccine designs that use virus-like particles (VLP) have shown efficacy for prophylactic vaccination against virus-associated cancer in the clinic. Here we used plant viral particles (PVP), which are structurally analogous to VLP, coupled to a weak idiotypic (Id) tumour antigen, as a conjugate vaccine to induce antibody against a murine B-cell malignancy. The Id-PVP vaccine incorporates a natural adjuvant, the viral ssRNA, which acts via TLR7. It induced potent protective anti-Id antibody responses in an in vivo mouse model, superior to the "gold standard" Id vaccine, with prevalence of the IgG2a isotype. Combination with alum further increased antibody levels and maintained the IgG2a bias. Engagement of TLR7 in vivo was followed by secretion of IFN-α by plasmacytoid dendritic cells and by activation of splenic CD11chi conventional dendritic cells. The latter was apparent from up-regulation of co-stimulatory molecules and from secretion of a wide range of inflammatory cytokines and chemokines including the Th1-governing cytokine IL-12, in keeping with the IgG2a antibody isotype distribution. PVP conjugates are a novel cancer vaccine design, offering an attractive molecular form, similar to VLP, and providing T-cell help. In contrast to VLP, they also incorporate a safe "in-built" ssRNA adjuvant.

Cytokine-modulating strategies and newer cytokine targets for arthritis therapy

Cytokines are the key mediators of inflammation in the course of autoimmune arthritis and other immune-mediated diseases. Uncontrolled production of the pro-inflammatory cytokines such as interferon-γ (IFN-γ), tumor necrosis factor α (TNFα), interleukin-6 (IL-6), and IL-17 can promote autoimmune pathology, whereas anti-inflammatory cytokines including IL-4, IL-10, and IL-27 can help control inflammation and tissue damage. The pro-inflammatory cytokines are the prime targets of the strategies to control rheumatoid arthritis (RA). For example, the neutralization of TNFα, either by engineered anti-cytokine antibodies or by soluble cytokine receptors as decoys, has proven successful in the treatment of RA. The activity of pro-inflammatory cytokines can also be downregulated either by using specific siRNA to inhibit the expression of a particular cytokine or by using small molecule inhibitors of cytokine signaling. Furthermore, the use of anti-inflammatory cytokines or cytokine antagonists delivered via gene therapy has proven to be an effective approach to regulate autoimmunity. Unexpectedly, under certain conditions, TNFα, IFN-γ, and few other cytokines can display anti-inflammatory activities. Increasing awareness of this phenomenon might help develop appropriate regimens to harness or avoid this effect. Furthermore, the relatively newer cytokines such as IL-32, IL-34 and IL-35 are being investigated for their potential role in the pathogenesis and treatment of arthritis.

Preclinical efficacy and safety of an anti-IL-1β vaccine for the treatment of type 2 diabetes

Neutralization of the inflammatory cytokine interleukin-1β (IL-1β) is a promising new strategy to prevent the β-cell destruction, which leads to type 2 diabetes. Here, we describe the preclinical development of a therapeutic vaccine against IL-1β consisting of a detoxified version of IL-1β chemically cross-linked to virus-like particles of the bacteriophage Qβ. The vaccine was well tolerated and induced robust antibody responses in mice, which neutralized the biological activity of IL-1β, as shown both in cellular assays and in challenge experiments in vivo. Antibody titers were long lasting but reversible over time and not associated with the development of potentially harmful T cell responses against IL-1β. Neutralization of IL-1β by vaccine-induced antibodies had no influence on the immune responses of mice to Listeria monocytogenes and Mycobacterium tuberculosis. In a diet-induced model of type 2 diabetes, immunized mice showed improved glucose tolerance, which was mediated by improved insulin secretion by pancreatic β-cells. Hence, immunization with IL-1β conjugated to virus-like particles has the potential to become a safe, efficacious, and cost-effective therapy for the prevention and long-term treatment of type 2 diabetes.

Virus-Like Particles, a Versatile Subunit Vaccine Platform

Virus-like particles (VLPs) can be spontaneously formed after expression of self-polymerising viral capsid proteins. VLPs structurally resemble their native source virus, maintaining immunological relevance by retaining formation of immunogenic motifs with natural conformation. The absence of the virus genome renders VLPs safe for administration as a subunit vaccine. VLPs can target both arms of the immune response, with some VLPs initiating production of specific antibodies and others activating cytotoxic T cells. VLPs are also exceptionally versatile, conferring protection against the host virus or acting as a scaffold for antigenic molecules. In addition, VLP can support intraparticulate encapsulation for immunomodulation and gene delivery. VLP vaccines have been developed for prophylactic protection against infectious organisms, and therapeutic treatment of conditions such as Alzheimer’s disease, hypertension, and cancer. With an expanding list of vaccine candidates, VLP vaccines are a promising field with a wide range of applications.

Employing an IL-23 p19 vaccine to block IL-23 ameliorates chronic murine colitis

BACKGROUND

Overexpression of IL-23 has been implicated in the pathogenesis of Crohn's disease. Using vaccines to block overexpressed endogenous cytokines has emerged as a new therapeutic strategy for the long-term treatment of the disease.

AIM

We sought to develop peptide-based vaccines specific to IL-23 and evaluate their effects in colitis mice.

MATERIALS & METHODS

The vaccine was developed by inserting a peptide derived from mouse IL-23 p19 into the carrier protein, hepatitis B core antigen, using molecular engineering methods. One vaccine against IL-23 p19 was obtained that induced high-titered and long-lasting antibodies to IL-23 without the use of adjuvants. The inhibitory effect of vaccine-immunized serum was subsequently evaluated in vitro. To evaluate the in vivo effects, mice were subcutaneously injected with the vaccine, carrier or saline three times. Two weeks after the last injection, chronic colitis was induced in mice by seven weekly administrations with 2,4,6-trinitrobenzene sulfonic acid.

RESULTS

In vitro studies revealed that serum IL-23 p19-specific IgG significantly suppressed IL-23-induced IL-17 production by splenocytes. In vivo evaluation of the effect of the vaccine in mice with chronic colitis indicated that vaccine-immunized mice exhibited a decrease in colon inflammation, collagen deposition and levels of IL-23 and IL-12 cytokines, compared with control groups.

CONCLUSION

IL-23 p19 vaccine is capable of downregulating inflammatory responses in chronic murine colitis, providing a novel therapeutic approach in Crohn's disease.

Prophylactic and therapeutic vaccines for obesity

Chronic diseases such as obesity and diabetes are major causes of death and disability throughout the world. Many causes are known to trigger these chronic diseases, and infectious agents such as viruses are also pathological factors. In particular, it is considered that adenovirus 36 infections may be associated with obesity. If this is the case, a vaccine against adenovirus 36 may be a form of prophylaxis to combat obesity. Other types of therapeutic vaccines to combat obesity are also being developed. Recently, hormones such as glucagon-like peptide-1, ghrelin, and peptide YY have been studied as treatments to prevent obesity. This review describes the ongoing development of therapeutic vaccines to treat obesity, and the possibility of using inactivated adenovirus 36 as a vaccine and an anti-obesity agent.

Attenuation of CCl4-induced hepatic fibrosis in mice by vaccinating against TGF-β1

Transforming growth factor β1 (TGF-β1) is the pivotal pro-fibrogenic cytokine in hepatic fibrosis. Reducing the over-produced expression of TGF-β1 or blocking its signaling pathways is considered to be a promising therapeutic strategy for hepatic fibrosis. In this study, we evaluated the feasibility of attenuating hepatic fibrosis by vaccination against TGF-β1 with TGF-β1 kinoids. Two TGF-β1 kinoid vaccines were prepared by cross-linking TGF-β1-derived polypeptides (TGF-β1(25)-[41-65] and TGF-β1(30)-[83-112]) to keyhole limpet hemocyanin (KLH). Immunization with the two TGF-β1 kinoids efficiently elicited the production of high-levels of TGF-β1-specific antibodies against in BALB/c mice as tested by enzyme-linked immunosorbent assay (ELISA) and Western blotting. The antisera neutralized TGF-β1-induced growth-inhibition on mink lung epithelial cells (Mv1Lu) and attenuated TGF-β1-induced Smad2/3 phosphorylation, α-SMA, collagen type 1 alpha 2 (COL1A2), plasminogen activator inhibitor-1 (PAI-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) expression in the rat hepatic stellate cell (HSC) line, HSC-T6. Vaccination against TGF-β1 with the kinoids significantly suppressed CCl4-induced collagen deposition and the expression of α-SMA and desmin, attenuated hepatocyte apoptosis and accelerated hepatocyte proliferation in BALB/c mice. These results demonstrated that immunization with the TGF-β1 kinoids efficiently attenuated CCl4-induced hepatic fibrosis and liver injury. Our study suggests that vaccination against TGF-β1 might be developed into a feasible therapeutic approach for the treatment of chronic fibrotic liver diseases.

Multi-therapeutic potential of autoantibodies induced by immune complexes trapped on follicular dendritic cells

Induction of autoantibodies (autoAbs) targeting disease drivers / mediators is emerging as a potential immunotherapeutic strategy. Auto-immune complex (IC)-retaining follicular dendritic cells (FDCs) critically regulate pathogenic autoAb production in autoreactive germinal centers (GCs); however, their ability to induce potentially therapeutic autoAbs has not been explored. We hypothesized that deliberate display of clinically targeted antigens (Ags) in the form of ICs on FDC membranes induces target-specific autoreactive GCs and autoAbs that may be exploited therapeutically. To test our hypothesis, three therapeutically relevant Ags: TNF-α, HER2/neu and IgE, were investigated. Our results indicated that TNF-α-, HER2/neu- and IgE-specific autoAbs associated with strong GC reactions were induced by TNF-α-, HER2/neu- and IgE-IC retention on FDCs. Moreover, the induced anti-TNF-α autoAbs neutralized mouse and human TNF-α with half maximal Inhibitory Concentration (IC₅₀) of 7.1 and 1.6 nM respectively. In addition, we demonstrated that FDC-induced Ab production could be non-specifically inhibited by the IgG-specific Endo-S that accessed the light zones of GCs and interfered with FDC-IC retention. In conclusion, the ability of FDCs to productively present autoAgs raises the potential for a novel immunotherapeutic platform targeting mediators of autoimmune disorders, allergic diseases, and Ab responsive cancers.

Enhanced neutralizing antibody titers and Th1 polarization from a novel Escherichia coli derived pandemic influenza vaccine

Influenza pandemics can spread quickly and cost millions of lives; the 2009 H1N1 pandemic highlighted the shortfall in the current vaccine strategy and the need for an improved global response in terms of shortening the time required to manufacture the vaccine and increasing production capacity. Here we describe the pre-clinical assessment of a novel 2009 H1N1 pandemic influenza vaccine based on the E. coli-produced HA globular head domain covalently linked to virus-like particles derived from the bacteriophage Qβ. When formulated with alum adjuvant and used to immunize mice, dose finding studies found that a 10 µg dose of this vaccine (3.7 µg globular HA content) induced antibody titers comparable to a 1.5 µg dose (0.7 µg globular HA content) of the licensed 2009 H1N1 pandemic vaccine Panvax, and significantly reduced viral titers in the lung following challenge with 2009 H1N1 pandemic influenza A/California/07/2009 virus. While Panvax failed to induce marked T cell responses, the novel vaccine stimulated substantial antigen-specific interferon-γ production in splenocytes from immunized mice, alongside enhanced IgG2a antibody production. In ferrets the vaccine elicited neutralizing antibodies, and following challenge with influenza A/California/07/2009 virus reduced morbidity and lowered viral titers in nasal lavages.

Strategies for active TNF-α vaccination in rheumatoid arthritis treatment

Local overexpression of tumor necrosis factors alpha (TNF-α) is critically involved in the inflammatory response and tissue destruction of rheumatoid arthritis (RA). Currently, the blockade of TNF-α by passive immunotherapy is indeed efficacious in the treatment of RA, but it still present some disadvantages. Induction of high level of anti-TNF-α neutralizing autoantibodies by TNF-α autovaccine has been developed to avoid these shortcomings. This review is to briefly introduce several vaccination approaches that have been used to induce a B cell response, including coupled TNF-α (entire/peptide) with a carrier protein, modified TNF-α with foreign Th cell epitopes, and engineered DNA vaccine. These methods showed remarkable therapeutic efficiency in experimental animals which indicated that active TNF-α immunization would be a promising and cost-effective new treatment option for RA.

A VLP-based vaccine against interleukin-1α protects mice from atherosclerosis

Interleukin (IL)-1α is a potent proinflammatory cytokine that has been implicated in the development of atherosclerosis. We investigated whether a vaccine inducing IL-1α neutralizing antibodies could interfere with disease progression in a murine model of atherosclerosis. We immunized Apolipoprothin E (ApoE)-deficient mice with a vaccine (IL-1α-C-Qβ) consisting of full-length, native IL-1α chemically conjugated to virus-like particles derived from the bacteriophage Qβ. ApoE(-/-) mice were administered six injections of IL-1α-C-Qβ or nonconjugated Qβ over a period of 160 days while being maintained on a western diet. Atherosclerosis was measured in the descending aorta and in cross-sections at the aortic root. Macrophage infiltration in the aorta was measured using CD68. Expression levels of VCAM-1, ICAM-1, and MCP-1 were quantified by RT-PCR. Immunization against IL-1α reduced plaque progression in the descending aorta by 50% and at the aortic root by 37%. Macrophage infiltration in the aorta was reduced by 22%. Inflammation was also reduced in the adventitia, with a decrease of 54% in peri-aortic infiltrate score and reduced expression levels of VCAM-1 and ICAM-1. Active immunization targeting IL-1α reduced both the inflammatory reaction in the plaque as well as plaque progression. In summary, vaccination against IL-1α protected ApoE(-/-) mice against disease, suggesting that this may be a potential treatment option for atherosclerosis.

Follicular dendritic cells in health and disease

Follicular dendritic cells (FDCs) are unique immune cells that contribute to the regulation of humoral immune responses. These cells are located in the B-cell follicles of secondary lymphoid tissues where they trap and retain antigens (Ags) in the form of highly immunogenic immune complexes (ICs) consisting of Ag plus specific antibody (Ab) and/or complement proteins. FDCs multimerize Ags and present them polyvalently to B-cells in periodically arranged arrays that extensively crosslink the B-cell receptors for Ag (BCRs). FDC-FcγRIIB mediates IC periodicity, and FDC-Ag presentation combined with other soluble and membrane bound signals contributed by FDCs, like FDC-BAFF, -IL-6, and -C4bBP, are essential for the induction of the germinal center (GC) reaction, the maintenance of serological memory, and the remarkable ability of FDC-Ags to induce specific Ab responses in the absence of cognate T-cell help. On the other hand, FDCs play a negative role in several disease conditions including chronic inflammatory diseases, autoimmune diseases, HIV/AIDS, prion diseases, and follicular lymphomas. Compared to other accessory immune cells, FDCs have received little attention, and their functions have not been fully elucidated. This review gives an overview of FDC structure, and recapitulates our current knowledge on the immunoregulatory functions of FDCs in health and disease. A better understanding of FDCs should permit better regulation of Ab responses to suit the therapeutic manipulation of regulated and dysregulated immune responses.

Vaccination with platelet-derived growth factor B kinoids inhibits CCl₄-induced hepatic fibrosis in mice

Platelet-derived growth factor B (PDGF-B) plays an essential role in hepatic fibrosis. Inhibition of the PDGF-B signaling in chronically injured livers might represent a potential therapeutic measure for hepatic fibrosis. In this study, we assessed the effects of vaccination against PDGF-B on CCl₄-induced liver fibrosis in BALB/c mice. The PDGF-B kinoid immunogens were prepared by cross-linking two PDGF-B-derived B-cell epitope peptides [PDGF-B¹⁶-(23-38) and PDGF-B¹⁶-(72-83)] to ovalbumin and keyhole limpet hemocyanin, respectively. Enzyme-linked immunosorbent assay, Western blotting, and NIH3T3 cell proliferation assay verified that immunization with the PDGF-B kinoids elicited the production of high levels of neutralizing anti-PDGF-B autoantibodies. The vaccination markedly alleviated CCl₄-induced hepatic fibrosis, as indicated by the lessened morphological alternations and reduced hydroxyproline contents in the mouse livers. Moreover, immunohistochemical staining for proliferating cell nuclear antigen, α-smooth muscle actin, and desmin demonstrated that neutralization of PDGF-B inhibited both the proliferation and the activation of hepatic stellate cells in the fibrotic mouse livers. Taken together, this study demonstrated that vaccination with PDGF-B kinoids significantly suppressed CCl₄-induced hepatic fibrosis in mice. Our results suggest that vaccination against PDGF-B might be developed into an effective, convenient, and safe therapeutic measure for the treatment of hepatic fibrosis.