Abstract
In this study, the photochemical internalization (PCI) technique was adopted in a nanoparticle-based antigen delivery system to enhance antigen-specific CD8+ T cell immune response for cancer immunotherapy. Pheophorbide A, a hydrophobic photosensitizer, grafted with polyethylenimine (PheoA-PEI) with endosome escape activity and near-infrared imaging capability was prepared. A model antigen ovalbumin (OVA) was then complexed with PheoA-PEI to form PheoA-PEI/OVA nanoparticles (PheoA-PEI/OVA NPs) that are responsive to light. Flow cytometry analysis revealed increased endocytosis in a murine dendritic cell line (DC2.4) that was treated with PheoA-PEI/OVA NPs compared to free OVA. Generation of reactive oxygen species (ROS) in DC2.4 cells was also confirmed quantitatively and qualitatively using 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA). Confocal laser scanning microscopy (CLSM) further demonstrated that the PheoA-PEI/OVA NPs enhanced cytosolic antigen release after light stimulation. Moreover, PheoA-PEI/OVA NP treated DC2.4 cells exhibited enhanced cross-presentation to B3Z T cell hybridoma in vitro after light irradiation, substantially increased compared to those treated with free OVA. Consistently, in vivo results revealed upregulation of CD3+CD8+T lymphocytes in tumors of mice treated with dendritic cells plus PheoA-PEI/OVA NPs and light irradiation. The activated T cell response is partly responsible for the inhibitory effect on E.G7 tumor growth in mice immunized with dendritic cells plus PheoA-PEI/OVA NPs and light irradiation. Our results demonstrate the feasibility to enhance antigen-specific CD8+ T cell immune response by light-responsive nanoparticle-based vaccine delivery for cancer immunotherapy.
Original language | English (US) |
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Pages (from-to) | 1760-1770 |
Number of pages | 11 |
Journal | Molecular pharmaceutics |
Volume | 14 |
Issue number | 5 |
DOIs | |
State | Published - May 1 2017 |
Bibliographical note
Publisher Copyright:© 2017 American Chemical Society.
Keywords
- antigen delivery
- cross-presentation
- endosome escape
- immunotherapy
- photochemical internalization