A programmable bispecific nano-immuno-engager promotes T cell homing and reprograms tumour microenvironment

Immune checkpoint blockade (ICB) therapy has revolutionized clinical oncology. However, the efficacy of ICB therapy is limited by the ineffective homing of T effector (Teff) cells to tumours and the immunosuppressive tumour microenvironment (TME). Here, we report a programmable tumour cells/Teff cells bispecific nano-immuno-engager (NIE) that can circumvent these limitations to improve ICB therapy. We have developed 28 nm non-toxic peptidic micellar nanoparticles (NIE-NPs) that bind α3β1 integrin on tumour cells membrane and undergo in situ transformation on surface of tumour cells into nanofibrillar network (NIE-NFs). The nanofibrillar network persistently facilitates cytotoxic T cells’ homing to the proximity of tumour cells via activatable α4β1 integrin ligands, and also allows sustained release of resiquimod to reprogram the TME. This bispecific NIE eliminates syngeneic 4T1 breast cancer and Lewis lung cancer models in mice, when given together with anti-PD-1 antibody. The in vivo structural transformation-based supramolecular bispecific NIE represents an innovative class of programmable receptor-mediated targeted immunotherapeutics to greatly enhance ICB therapy against cancers.