The TLR7/8 agonist INI-4001 enhances the immunogenicity of a Powassan virus-like-particle vaccine.

Powassan virus (POWV) is a pathogenic tick-borne flavivirus that causes fatal neuroinvasive disease in humans. There are currently no approved therapies or vaccines for POWV infection. Here, we develop a POW virus-like-particle (POW-VLP) based vaccine adjuvanted with the novel synthetic Toll-like receptor 7/8 agonist INI-4001.

Systematic Evaluation of Regiochemistry and Lipidation of Aryl Trehalose Mincle Agonists.

The Macrophage-Inducible C-type Lectin receptor (Mincle) plays a critical role in innate immune recognition and pathology, and therefore represents a promising target for vaccine adjuvants. Innovative trehalose-based Mincle agonists with improved pharmacology and potency may prove useful in the development of Th17-mediated adaptive immune responses. Herein, we report on in vitro and in silico investigations of specific Mincle ligand-receptor interactions required for the effective receptor engagement and activation of Th17-polarizing cytokines.

Intranasal administration of a synthetic TLR4 agonist INI-2004 significantly reduces allergy symptoms following therapeutic administration in a murine model of allergic sensitization.

Introduction: Atopic diseases have been steadily increasing over the past decades and effective disease-modifying treatment options are urgently needed. These studies introduce a novel synthetic Toll-like receptor 4 (TLR4) agonist, INI-2004, with remarkable efficacy as a therapeutic intranasal treatment for seasonal allergic rhinitis.

Methods: Using a murine airway allergic sensitization model, the impact of INI-2004 on allergic responses was assessed.

Vaccination with Mincle agonist UM-1098 and mycobacterial antigens induces protective Th1 and Th17 responses.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is one of the top infectious killers in the world. The only licensed vaccine against TB, Bacille Calmette-Guérin (BCG), provides variable protection against pulmonary TB, especially in adults. Hence, novel TB vaccine approaches are urgently needed.

Promotion of Th17 Polarized Immunity via Co-Delivery of Mincle Agonist and Tuberculosis Antigen Using Silica Nanoparticles.

Adjuvants and immunomodulators that effectively drive a Th17-skewed immune response are not part of the standard vaccine toolkit. Vaccine adjuvants and delivery technologies that can induce Th17 or Th1/17 immunity and protection against bacterial pathogens, such as tuberculosis (TB), are urgently needed. Th17-polarized immune response can be induced using agonists that bind and activate C-type lectin receptors (CLRs) such as macrophage inducible C-type lectin (Mincle).

Adjuvanted Vaccine Induces Functional Antibodies against Filamentous Bacteriophages.

(), a WHO priority 1 pathogen, resulted in approximately 559,000 deaths globally in 2019. has a multitude of host-immune evasion strategies that enhance virulence. Most clinical isolates of are infected by a phage called Pf that has the ability to misdirect the host-immune response and provide structural integrity to biofilms.

Diamino Allose Phosphates: Novel, Potent, and Highly Stable Toll-like Receptor 4 Agonists.

Most known synthetic toll-like receptor 4 (TLR4) agonists are carbohydrate-based lipid-A mimetics containing several fatty acyl chains, including a labile 3--acyl chain linked to the C-3 position of the non-reducing sugar known to undergo cleavage impacting stability and resulting in loss of activity. To overcome this inherent instability, we rationally designed a new class of chemically more stable synthetic TLR4 ligands that elicit robust innate and adaptive immune responses. This new class utilized a diamino allose phosphate (DAP) scaffold containing a nonhydrolyzable 3-amide bond instead of the classical 3-ester.

Self-Adjuvanting TLR7/8 Agonist and Fentanyl Hapten Co-Conjugate Achieves Enhanced Protection against Fentanyl Challenge.

Currently approved pharmacotherapies for opioid use disorders (OUDs) and overdose reversal agents are insufficient to slow the spread of OUDs due to the proliferation of fentanyl. This is evident in the 31% rise in drug overdose deaths from 2019 to 2022, with rates increasing from 21.6 to 28.

A TLR7/8 agonist increases efficacy of anti-fentanyl vaccines in rodent and porcine models.

Opioid use disorders (OUD) and overdose are public health threats worldwide. Widespread access to highly potent illicit synthetic opioids such as fentanyl is driving the recent rise in fatal overdoses. Vaccines containing fentanyl-based haptens conjugated to immunogenic carrier proteins offer a long-lasting, safe, and cost-effective strategy to protect individuals from overdose upon accidental or deliberate exposure to fentanyl and its analogs.

A lipidated TLR7/8 adjuvant enhances the efficacy of a vaccine against fentanyl in mice.

Opioid use disorders (OUD) and opioid-related fatal overdoses are a public health concern in the United States. Approximately 100,000 fatal opioid-related overdoses occurred annually from mid-2020 to the present, the majority of which involved fentanyl or fentanyl analogs. Vaccines have been proposed as a therapeutic and prophylactic strategy to offer selective and long-lasting protection against accidental or deliberate exposure to fentanyl and closely related analogs.

Synthesis and Biological Evaluation of Trehalose-based Bi-aryl Derivatives as C-type Lectin Ligands.

The identification of Mincle as the C-type lectin receptor on innate immune cells responsible for binding TDM and the realization that this receptor could be key to productive vaccines for mycobacterial infection has raised interest in the development of synthetic Mincle ligands as novel adjuvants. We recently reported on the synthesis and evaluation of Brartemicin analog UM-1024 that demonstrated Mincle agonist activity, exhibiting potent Th1/Th17 adjuvant activity that was greater than that of trehalose dibehenate (TDB). Our pursuit to understand Mincle/ligand relationships and improve the pharmacologic properties of the ligands has expanded and continues to reveal new and exciting structure activity relationships.

Using Dual Toll-like Receptor Agonism to Drive Th1-Biased Response in a Squalene- and α-Tocopherol-Containing Emulsion for a More Effective SARS-CoV-2 Vaccine.

A diversity of vaccines is necessary to reduce the mortality and morbidity of SARS-CoV-2. Vaccines must be efficacious, easy to manufacture, and stable within the existing cold chain to improve their availability around the world. Recombinant protein subunit vaccines adjuvanted with squalene-based emulsions such as AS03™ and MF59™ have a long and robust history of safe, efficacious use with straightforward production and distribution.

Advancing Adjuvants for Therapeutics.

Tuberculosis (TB) remains one of the leading causes of death worldwide due to a single infectious disease agent. BCG, the only licensed vaccine against TB, offers limited protection against pulmonary disease in children and adults. TB vaccine research has recently been reinvigorated by new data suggesting alternative administration of BCG induces protection and a subunit/adjuvant vaccine that provides close to 50% protection.

Design of Trehalose-Based Amide/Sulfonamide C-type Lectin Receptor Signaling Compounds.

Mincle agonists have been shown to induce inflammatory cytokine production, such as tumor necrosis factor-alpha (TNF) and promote the development of a Th1/Th17 immune response that might be crucial to development of effective vaccination against pathogens such as Mycobacterium tuberculosis. As an expansion of our previous work, a library of 6,6'-amide and sulfonamide α,α-d-trehalose compounds with various substituents on the aromatic ring was synthesized efficiently in good to excellent yields. These compounds were evaluated for their ability to activate the human C-type lectin receptor Mincle by the induction of cytokines from human peripheral blood mononuclear cells.

Co-adsorption of synthetic Mincle agonists and antigen to silica nanoparticles for enhanced vaccine activity: A formulation approach to co-delivery.

To date there is no clinically approved adjuvant to drive a protective T-helper cell 17 (Th17) immune response against Mycobacterium tuberculosis (Mtb). Trehalose Dimycolate (TDM) is a glycolipid molecule found in the cell wall of Mtb and similar species. Our team has discovered novel synthetic TDM derivatives that target Mincle receptors and when presented on the surface of amine functionalized silica nanoparticles (A-SNPs) adopt the requisite supramolecular structure for Mincle receptor agonism.

Towards Precision Vaccines: Lessons From the Second International Precision Vaccines Conference.

Other than clean drinking water, vaccines have been the most effective public health intervention in human history, yet their full potential is still untapped. To date, vaccine development has been largely limited to empirical approaches focused on infectious diseases and has targeted entire populations, potentially disregarding distinct immunity in vulnerable populations such as infants, elders, and the immunocompromised. Over the past few decades innovations in genetic engineering, adjuvant discovery, formulation science, and systems biology have fueled rapid advances in vaccine research poised to consider demographic factors (, age, sex, genetics, and epigenetics) in vaccine discovery and development.

MPL Adjuvant Contains Competitive Antagonists of Human TLR4.

Monophosphoryl lipid A (MPL) is the first non-alum vaccine adjuvant to achieve widespread clinical and market acceptance, a remarkable achievement given that it is manufactured from a endotoxin. To understand how MPL successfully balanced the dual mandate of vaccine design-low reactogenicity with high efficacy-clinical- and research-grade MPL was evaluated in human and mouse cell systems. Stimulatory dose response curves revealed that most preparations of MPL are much more active in mouse than in human cell systems, and that the limited efficacy observed in human cells correlated with TLR4 inhibitory activity that resulted in a partial agonist profile.

6,6'-Aryl trehalose analogs as potential Mincle ligands.

6,6'-Aryl trehalose derivatives have been synthesized with a view towards identifying novel Th-17-inducing vaccine adjuvants based on the high affinity Mincle ligand Brartemicin. The initial structure-activity relationships of these novel trehalose-based compounds were investigated. All compounds have been evaluated for their ability to engage the Mincle receptor and induce a potential pro-Th17 cytokine profile from human peripheral blood mononuclear cells based on IL-6 production in human peripheral blood mononuclear cells.

Novel Lipidated Imidazoquinoline TLR7/8 Adjuvants Elicit Influenza-Specific Th1 Immune Responses and Protect Against Heterologous H3N2 Influenza Challenge in Mice.

Most licensed seasonal influenza vaccines are non-adjuvanted and rely primarily on vaccine-induced antibody titers for protection. As such, seasonal antigenic drift and suboptimal vaccine strain selection often results in reduced vaccine efficacy. Further, seasonal H3N2 influenza vaccines demonstrate poor efficacy compared to H1N1 and influenza type B vaccines.

Optimization of 8-oxoadenines with toll-like-receptor 7 and 8 activity.

Toll-like receptors 7 and 8 (TLR7/8) agonists are potent immunostimulants that are attracting considerable interest as vaccine adjuvants. We recently reported the synthesis of a new series of 2-O-butyl-8-oxoadenines substituted at the 9-position with various linkers and N-heterocycles, and showed that TLR7/8 selectivity, potency and cytokine induction could be modulated by varying the alkyl linker length and the N-heterocyclic ring. In the present study, we further optimized the oxoadenine scaffold by investigating the effect of different substituents at the 2-position of the oxoadenine on TLR7/8 potency/selectivity, cytokine induction and DC maturation in human PBMCs.

Aryl Trehalose Derivatives as Vaccine Adjuvants for .

() continues to be a major health threat worldwide, and the development of vaccines could play a pivotal role in the prevention and control of this devastating epidemic. Th17-mediated immunity has been implicated in disease protection correlates of immune protection against . Currently, there are no approved adjuvants capable of driving a Th17 response in a vaccine setting.