AUTHOR=Deak Peter , Kimani Flora , Cassaidy Brittney , Esser-Kahn Aaron TITLE=Determining Whether Agonist Density or Agonist Number Is More Important for Immune Activation via Micoparticle Based Assay JOURNAL=Frontiers in Immunology VOLUME=11 YEAR=2020 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2020.00642 DOI=10.3389/fimmu.2020.00642 ISSN=1664-3224 ABSTRACT=

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.