Antigen-capturing nanoparticles improve the abscopal effect and cancer immunotherapy

Immunotherapy holds tremendous promise for improving cancer treatment¹. To administer radiotherapy with immunotherapy has been shown to improve immune responses and can elicit the ‘abscopal effect’². Unfortunately, response rates for this strategy remain low³. Herein we report an improved cancer immunotherapy approach that utilizes antigen-capturing nanoparticles (AC-NPs). We engineered several AC-NP formulations and demonstrated that the set of protein antigens captured by each AC-NP formulation is dependent on the NP surface properties. We showed that AC-NPs deliver tumour-specific proteins to antigen-presenting cells (APCs) and significantly improve the efficacy of αPD-1 (anti-programmed cell death 1) treatment using the B16F10 melanoma model, generating up to a 20% cure rate compared with 0% without AC-NPs. Mechanistic studies revealed that AC-NPs induced an expansion of CD8⁺ cytotoxic T cells and increased both CD4⁺T/T_reg and CD8⁺T/T_reg ratios (T_reg, regulatory T cells). Our work presents a novel strategy to improve cancer immunotherapy with nanotechnology.