(615g) The Effect of Length and Terminal Group of Poly(ethylene glycol)-Terminated Self-Assembled Monolayers (SAMs) On Dendritic Cell (DC) Maturation and Function

Dendritic cells (DCs) are the most potent antigen presenting cells (APCs). They are the primary target for inducing effective immune responses or tolerance. Ex-vivo induced DCs have been used for immunotherapy of cancers. DCs are present around implanted devices though their functions remain to be elucidated. Oligomers or polymers of ethylene glycol (EG) have been grafted onto surfaces of various biomaterials for controlling protein adsorptions and increasing the biocompatibility of devices. In this study, immature DCs were exposed to poly(ethylene glycol) (PEG)-terminated self-assembled monolayers (SAMs). OH-terminated PEG SAMs activated immature DCs and upregulated surface molecules characteristic of mature DCs at a higher degree than COOH-terminated ones. Longer OH-terminated PEG SAM encouraged the maturation of DCs at a higher magnitude than shorter ones. Interestingly, none of SAMs induced cytokines characteristic of either inflammatory or tolerogenic DCs. Additionally, we demonstrated that OH-terminated PEG SAM activated DCs mainly through DAP-12 or Fc-gamma – associated surface receptors-dependent pathway. Our results give insights into biomaterial design for inducing activation or tolerance of DC-based immunity. Since DAP-12 or Fc-gamma – associated surface receptors-dependent signaling pathway is involved in many cell types, including macrophages, our results also suggest that PEG-terminated SAMs can potentially activate other cell types in a length and functional end-dependent manner.