Covalently anchored PD-L1 nanostructures recruit and activate T cells, enhancing antitumor immunity.

Effective cancer immunotherapy often relies on robust T cell recruitment and activation while simultaneously overcoming immune suppression. Current strategies predominantly focus on blocking the PD-1/PD-L1 axis, a critical immune checkpoint, but often overlook the potential to actively reprogram immune functions directly on the tumor cell surface. This gap limits the efficacy of existing immune checkpoint blockades, necessitating novel approaches that can both inhibit suppressive pathways and actively engage immune cells to amplify antitumor responses.

Researchers developed a "localized oxidation-covalent assembly" strategy to precisely modify PD-L1 on the cell surface. This involved glycan oxidation to create reactive sites, followed by bioorthogonal reactions to induce the in situ construction of artificial topological nanostructures (ATNs). They investigated the mechanism, identifying N-glycosylation sites as critical for probe-mediated aldehyde modification of PD-L1. The study then assessed how these ATNs augment T cell-mediated antitumor immunity and achieve spatially precise T cell recruitment and activation.

The engineered artificial topological nanostructures (ATNs) demonstrated a dual function, effectively blocking the PD-1/PD-L1 axis to relieve immune suppression. Simultaneously, these ATNs actively recruited and activated T cells through transmembrane bridging interactions, functionally mimicking bispecific T cell engagers (BiTEs). This combined action led to a marked enhancement of antitumor immune responses. Mechanistic investigations revealed that N-glycosylation sites on PD-L1 are critical for the probe-mediated aldehyde modification, which is essential for ATN formation. > The ATNs achieved spatially precise T cell recruitment and activation, directly dependent on PD-L1 localization, enabling programmable immune regulation. This indicates a highly controlled and targeted modulation of the immune microenvironment.