Enhanced Stimulation of Anti-Ovarian Cancer CD8+T Cells by Dendritic Cells Loaded with Nanoparticle Encapsulated Tumor Antigen

Problem Dendritic cell (DC)-based cancer therapies are favored approaches to stimulate anti-tumor T-cell responses. Unfortunately, tolerance to tumor antigens is difficult to overcome. Biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NP) are effective reagents in the delivery of drugs and tumor-associated antigens (TAA). In this study, we assessed the capacity of a PLGA NP-based delivery system to augment CD8 T-cell responses to ovarian cancer TAA. Method of Study Human DC were generated from blood monocytes by conventional in vitro differentiation and loaded with either soluble tumor lysate or NP/lysate conjugates (NPL). These antigen-loaded DC were then used to stimulate autologous CD8+ T cells. Cytokine production and activation markers were evaluated in the CD8+ T cells. Results DC loading with NPL increased cytokine production by stimulated CD8 T cells and induced T-cell expression of cell surface co-stimulatory molecules, typical of anti-tumor immune responses. In contrast, delivery of naked tumor lysate antigens preferentially induced a T-cell profile characteristic of tolerization/exhaustion. Conclusion These findings indicate that delivery of TAA in NP enables DC to efficiently activate anti-tumor CD8+ T cells. PLGA NP encapsulation of tumor-derived lysate protein antigens is an encouraging new preparative methodology for DC-based vaccination meriting clinical testing.