Engineered\nPlatelet for <i>In Situ</i> Natural\nKiller Cell Activation to Inhibit Tumor Recurrence

Natural killer (NK) cells offer profound advantages against\ntumor\nrecurrence due to their unique immunological behavior. NK cell therapies\nassociated with the antibody-dependent cell-mediated cytotoxicity\n(ADCC) effect have made remarkable progress while being limited by\ninsufficient antibody binding and the exhausted state of NK cells\nin the postsurgical immunosuppressive microenvironment. Leveraging\nthe adherence of PLT to tumor cells, we developed an exogenously implanted\nplatelet (PLT)-based NK cell-driven system (PLT-IgG-IL15) to improve\nthe identifiability of residual tumors with IgG antibody labeling\nfor NK cells catching and engaging, which consequently restored the\nADCC effect and promoted the recovery of their killing function. Furthermore,\ninterleukin-15 (IL-15) participated in the augmentation of NK cell\nfunction. Collectively, PLT-IgG-IL15 served as an NK cell tumor cell\nengager as well as an NK cell charger, achieving a <40% recurrence\nrate in mouse tumor models.