Targeted tumor coating with antigenic, CTL-recognizable peptides via Annexin A5 chimeric constructs following chemotherapy redirects adaptive CD8+ T cell immunity for tumor clearance

摘要

A common drawback of many cancer immunotherapies,including immune checkpoint blockade,is their reliance on the expression of immunogenic tumor antigens by cancer cells for immune recognition and clearance,which limits their efficacy against cancers with weak antigenicity.1 To overcome this obstacle,we and others have explored strategies to harness the immune responses against nontumor antigens and redirect those immune responses to target tumor cells.2,3,4,5 In particular,we have pioneered a therapeutic strategy fusing tumor-targeting proteins with known antigenic peptide epitopes not naturally expressed by tumor cells,which are flanked by peptide sequences that can be recognized and cleaved by proteases overexpressed in most cancers.2,3 This strategy facilitates the targeted delivery of immunogenic peptides into tumor foci,the release of immunogenic peptides into the tumor microenvironment(TME)via tumor protease cleavage,and subsequent loading of these peptides onto major histocompatibility complex class 1(MHC-I)on the tumor cell surface,allowing the recognition of coated tumor cells by the respective peptide-specific cytotoxic CD8+T lymphocytes(CTLs)for elimination.