Abstract

1. In vitro characterization In vivo testing Bone marrow isolation – GMCSF +/- IL4 Replate cells w/ GMCSF +/- IL4 Add PMPs Media change– GMCSF +/- IL4 Dendritic cell subsets interact with CpG-carryingpathogen mimicking particles in a phenotype specific manner Jardin Leleux, PallabPradhan and Krishnendu RoyDepartment of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GAEmory School of Medicine, Emory University, Atlanta, GA Media change– GMCSF +/- IL4 End DC subset preference for delivery format varies with phenotype : (left) Cultures treated with only GMCSF produce cells that take up more CpG on average than cultures supplemented with IL4 or plasmacytoid DCs. (right) PDL2- cDCs and pDCs increase activation marker CD86 expression when CpG is delivered using NP formulations. PDL2+ cDCs prefer MPs to NP delivered CpG. DC subsets are targeted in vivo by particle formulations. Microparticles are trafficked to draining lymph nodes one day following vaccination. Additionally, MPs preferentially recruit CD103+ cDCs while NPs recruit Langerhans cells. DC subset isolation • PDL2+ conventional DCs: • Increase w/ IL4 • Th2 polarizing • Antigen-presenting • Plasmacytoid DCs: • Th1 polarizing • Not efficient antigen-presenting cells • PDL2- conventional DCs: • Th1 or Th2 signals • Antigen-presenting Abstract Biomaterial-based vaccine carriers are being widely investigated for delivery of antigens and adjuvants. Multiple DC subsets reside in the tissue and are an essential aspect of the cellular immune response. GOAL: Study the preference and efficacy of tissue resident DC subsets for PLGA-pathogen mimicking particles (PMPs) to modulate cellular immune response. Particle delivered vaccines provide better protection to OVA-melanoma challenged mice.Microparticles and nanoparticles carrying OVA antigen and CpG provide significantly better protection than positive and negative controls in a therapeutic model. Tumor 1stInjBoosters Conclusion PLGA particles serve as an efficient vehicle for delivery of antigen and immunostimulatory molecules to DCs. Additionally, our preliminary data show that they may also provide a means of physically targeting individual subsets of DCs that can direct resultant immune responses. . References • Singh, A., Qin, H., Fernandez, I., Wei, J., Lin, J., Kwak, L. W., Roy, K. 2011. An injectable synthetic immune-priming center mediates efficient T-cell class switching and T-helper 1 response against T cell lymphoma. J Cont Release 155(2): 184 • Acknowledgments: We are grateful to NSF Graduate Research Fellowship, Georgia Institute of Technology and Emory University School of Medicine for funding this research. 0 2 4 6 7 days 0 12 19 26 days PDL2+ cells produce majority of cytokines in IL4 cultures. (top panel) cDCs treated with IL4 yield more cytokine producing cells and of those the majority are PDL2+. (bottom panel) IL4 does not induce more intracellular cytokine production on average in activated cells. PDL2+ cells activate CD8+ and CD4+ T cells in an antigen specific manner: PDL2+ cDCs pulsed with OVA antigen efficiently induce upregulation of activation marker CD25 on OVA-specific T cells.