Manufacture And Application Of The Versatile Dendritic Cell-based Artificial-antigen Presenting Cell

The efficacy of adoptive cell transfer therapy against tumors greatly relies on the manufacture of efficient artificial antigen presenting cells(aAPCs).The aAPC system is considered as a mimic to the antigen presenting process toward T lymphocytes performed by dendritic cells(DCs).In general,two signals are essential to be involved in the aAPC platforms,both cellular and acellular,including the antigen recognition ligand and the costimulation molecules,in which case T cells are activated in vitro.Subsequently the largely expanded T cells are infused back to the patients to eliminate the tumor cells in an antigen specific manner.The based-aAPCs on cellular platforms activate T cells with high fidelity to the natural way accomplished by DCs.However,there has been some limitations to the selection of the cell line.Also,it has difficulties to ensure the safety of biological agents and to highly express the HLA and the costimulation molecules on cell-based aAPCs.These situations can be circumvented by utilizing micro and nano scale platforms,though,the material-based nano structures are not in favor of antigen presenting in vivo due to the issue of small size that they are easily cleared by the body fluid and thus hard to target the lymph node.Meanwhile,the rigidity of material surface would hinder the rearrangement of receptors on T cells during activation,which impair the outcome of T cell activation.To address these problems mentioned above,a DC-based aAPC was manufactured.The membrane of DC was first derived with azide group through the metabolic incorporation of AECho into phospholipids,then the DBCO-modified stimuli molecules were conjugated to the membrane by the bioorthogonal reaction between azide and DBCO groups.Meanwhile,the DC was induced to mature phenotype by the addition of clustered superparamagnetic nanoparticles(Fe3O4 cluster).The two strategies were combined to prepared the versatile DC-based aAPC.The result indicated the successful induction of DC maturation by the elevated expression of several costimulation molecules and the secretion of IL-12p70.In addition,large amount of stimulation molecules was confirmed to be immobilized to the surface of cell membrane by the bioorthogonal reaction,which accordingly promoted the in vitro expansion of T cells by this DC-aAPC system.Furthermore,the uptake of Fe3O4 cluster also upregulated the expression of CCR7,which mediated the enhanced homing ability to peripheral lymph nodes of DC,assisted by external magnetic field.Finally,it was applied to the magnetic resonance imaging(MRI)in vivo to monitor the accelerated accumulation of DC-aAPC in lymph node under magnetic field.Briefly,the DC was modified to overcome the disadvantage for biosafety concerns of cellular platforms,and can be conjugated with stimuli molecules as the material-based ones do.It showed improved T cell expansion and lymph node targeting ability owning to the expression of costimulation molecules and chemokine receptors.Moreover,it harnessed the property of Fe3O4 cluster to perform the MRI of the DC-aAPC platform,suggesting the capability of tracking the homing dynamics of DC in vivo.In conclusion,all these results proved the availability of this DC-based aAPC system in vivo,and the potential as a potent candidate for tumor immunotherapy.