Development of a peptide conjugate vaccine for inducing therapeutic anti-IgE antibodies

Peptide cargo administration: current state and applications

Effective delivery of drug molecules to the target site is a challenging task. In the last decade, several innovations in the drug delivery system (DDS) have tremendously improved the therapeutic efficacy of drug molecules. Among various DDS, cell-penetrating peptides (CPPs) based DDS have gathered notable attention owing to their safety, efficacy, selectivity, specificity, and ease of synthesis. CPPs are emerging as an efficient and effective pharmaceutical nanocarriers-based platforms for successful management of various important human health disorders. Failure of several current chemotherapeutic strategies is attributed to low solubility, reduced bioavailability, and off-target delivery of several anti-cancer drugs. Similarly, development of therapeutics for vision-threatening disorders is challenged by the anatomical as well as physiological complexity of the eye. Such therapeutic challenges in cancer and ocular disease management can be overcome by developing cell-penetrating peptide (CPP) based peptide drug conjugates (PDCs). CPPs can be used to deliver various types of cargo molecules including nucleic acids, small molecules, and peptides/proteinaceous agents. In this review, we have briefly introduced CPPs and the linker strategies employed for the development of PDCs. Furthermore, recent studies employing CPP-based PDCs for cancer and ocular disease management have been discussed in detail highlighting their significance over conventional DDS. Later sections of the review are focused on the current status of clinical trials and future implications of CPP-based PDCs in vaccine development. KEY POINTS: • Cell-penetrating peptides (CPPs) can deliver a variety of cargo macromolecules via covalent and non-covalent conjugation. • CPP-based peptide drug conjugates (PDCs) can overcome drawbacks of conventional drug delivery methods such as biocompatibility, solubility, stability, and specificity. • Various PDCs are in clinical trial phase for cancer and ocular therapeutics.

Epitope targeting with self-assembled peptide vaccines

Nanoparticle-based delivery systems are being used to simplify and accelerate new vaccine development. Previously, we described the solid-phase synthesis of a 61-amino acid conjugate vaccine carrier comprising a α-helical domain followed by two universal T cell epitopes. Circular dichroism, analytical centrifugation, and dynamic light scattering indicate that this carrier forms coiled-coil nanoparticles. Here we expand the potential of this carrier by appending B cell epitopes to its amino acid sequence, thereby eliminating the need for traditional conjugation reactions. Peptides containing Tau or amyloid-β epitopes at either terminus assemble into ~20 nm particles and induce antibody responses in outbred mice. Vaccine function was verified in three experiments. The first targeted gonadotropin-releasing hormone, a 10-amino acid neuropeptide that regulates sexual development. Induction of peak antibody titers in male mice stimulated a dramatic loss in fertility and marked testis degeneration. The second experiment generated antibodies to an epitope on the murine IgE heavy chain analogous to human IgE sequence recognized by omalizumab, the first monoclonal antibody approved for the treatment of allergic asthma. Like omalizumab, the anti-IgE antibodies in immunized mice reduced the concentrations of circulating free IgE and prevented IgE-induced anaphylaxis. Finally, a peptide containing the highly conserved Helix A epitope within the influenza hemagglutinin stem domain induced antibodies that successfully protected mice against a lethal H1N1 challenge. These results establish the utility of a new vaccine platform for eliciting prophylactic and therapeutic antibodies to linear and helical B cell epitopes.

Synthetic nanoparticles have the potential to be a simple, efficacious, and customizable platform for vaccine delivery. Christopher H. Clegg and colleagues include B cell epitopes on a self-assembling α-helical peptide nanoparticle carrier in order to elicit robust antibody generation. This novel vaccine platform is validated in vivo to produce physiologically-relevant antibodies in three different settings: an antibody-mediated ‘castration’ approach (anti-gonadotropin-releasing hormone), depletion of IgE (by generation of anti-IgE), and finally production of antibodies to a conserved H1N1 influenza epitope that mediates a protective effect in mice.

Novel therapeutic targets for allergic airway disease in children

The aim of precision medicine is setting up targeted therapies for selected patients that would ideally have high effectiveness and few side effects. This is made possible by targeted therapy drugs that selectively act on a specific pathway. Precision medicine is spreading to many medical specialties, and there is increasing interest in the context of allergic airway diseases, such as allergic rhinitis, chronic rhinosinusitis, and asthma. This review is an update of new targets in the treatment of childhood allergic upper airway diseases and asthma, including the most recent biologic drugs that have already been licensed or are in the pipeline to be tested with children.

New approaches for identifying and testing potential new anti-asthma agents

INTRODUCTION

Asthma is a chronic disease with significant heterogeneity in clinical features, disease severity, pattern of underlying disease mechanisms, and responsiveness to specific treatments. While the majority of asthmatic patients are controlled by standard pharmacological strategies, a significant subgroup has limited therapeutic options representing a major unmet need. Ongoing asthma research aims to better characterize distinct clinical phenotypes, molecular endotypes, associated reliable biomarkers, and also to develop a series of new effective targeted treatment modalities. Areas covered: The expanding knowledge on the pathogenetic mechanisms of asthma has allowed researchers to investigate a range of new treatment options matched to patient profiles. The aim of this review is to provide a comprehensive and updated overview of the currently available, new and developing approaches for identifying and testing potential treatment options for asthma management. Expert opinion: Future therapeutic strategies for asthma require the identification of reliable biomarkers that can help with diagnosis and endotyping, in order to determine the most effective drug for the right patient phenotype. Furthermore, in addition to the identification of clinical and inflammatory phenotypes, it is expected that a better understanding of the mechanisms of airway remodeling will likely optimize asthma targeted treatment.