Determining Whether Agonist Density or Agonist Number Is More Important for Immune Activation via Micoparticle Based Assay

It is unknown if surface bound toll-like-receptor (TLR) agonists activate cells via density or total molecular number. To answer this question, we developed a TLR agonist surface conjugated polystyrene microparticle (MP) system. Using a library of MPs with varying TLR agonist density and number, we simultaneously observed innate immune cell MP uptake and TNFα expression using ImageStream flow cytometry on a cell by cell basis. The data shows that total TLR number and not density drives cellular activation with a threshold of approximately 105-106 TLR agonists. We believe that this information will be crucial for the design of particulate vaccine formulations.

Correlating the structure and reactivity of a contact allergen, DNCB, and its analogs to sensitization potential

We report a study that seeks to find a correlation between the overall sensitization potential quantified by the expression of IL-8 by stimulated monocytes and the chemical structure of a model contact allergen, 2,4-dinitrochlorobenzene (DNCB). We show that structure and reactivity of the chemical compounds play an important role in activation of the monocytes and subsequent inflammation in tissue. However, we observed a non-linear correlation between the rate of reaction and biological activity indicating a required balance of stability and reactivity.

Development of adjuvant scaffolds from small molecule contact allergens

Small molecule contact allergens are an understudied class of immunostimulatory compounds that have the potential of being developed into adjuvants. Vaccines remain the most effective tool in preventing disease and adjuvants serve to make vaccines more efficacious by activating the innate immunity. To develop contact allergens molecules as adjuvants, we began by first elucidating the mechanism of allergic contact hypersensitivity. Using contact allergens and their analogues we wanted to define the structural elements necessary for the activation of immune cells. Our initial experiments sought to correlate sensitization potential to chemical reactivity where the latter influenced the initial phase of sensitization, hapten formation. We showed that there is a non-linear relationship between the rate of reactivity of the compounds and the ability to induce IL-8 expression on THP-1 cells. This result suggested that contact allergens modify specific target proteins and hence sterics, as well as electronic nature of the contact allergen, play an important role. Using the insights from this initial study we are developing probes that will allow the identification of the hapten-protein complex formed during the sensitization process in order to understand the recognition mechanism of this complex to immune cell receptors. We envision this study as the first step towards the development of potent adjuvants from contact allergen scaffolds. Additionally, the elucidation of the protein targets of small molecule contact allergens will reveal therapy avenues for the treatment of allergic contact hypersensitivity.

Rapid in Situ Generation of Benzene Diazonium Ions under Basic Aqueous Conditions from Bench-Stable Triazabutadienes

Aryl diazonium ions are useful across a range of chemical/biochemical areas. These species are generally made using strongly acidic conditions, which can be detrimental to acid-sensitive functional groups. The ability to generate benzene diazonium ions under basic aqueous conditions is reported herein along with newfound understanding on the aqueous reactivity of solubilized triazabutadienes whereby π-interactions appear to confer a large degree of stability.