Tumor antigen-presenting cell

A tumor antigen-presenting cell (APC) refers to any cell capable of processing and displaying tumor-derived antigens on its surface, typically via major histocompatibility complex (MHC) molecules, to activate T cells and initiate an adaptive immune response against cancer. While all nucleated cells can present antigens through MHC class I, the term "antigen-presenting cell" usually denotes specialized immune cells—dendritic cells, macrophages, and B cells—that are particularly efficient at this process. Dendritic cells are considered the most potent professional APCs for initiating anti-tumor immunity because they efficiently prime naïve T-cells in lymph nodes after migrating from the tumor site. Tumors often evade immune detection by downregulating components of their own antigen processing/presentation machinery (e.g., loss/mutation of proteasome subunits or TAP transporters; reduced HLA/MHC expression), suppressing dendritic cell function within the microenvironment, or altering their antigen repertoire. Artificial/APC-based vaccines are being developed as next-generation therapeutics: these use engineered dendritic or other accessory-like artificial APCs loaded with defined TAAs/neoantigens to boost patient-specific anti-tumor responses.

Checkpoint inhibitors: Restore T cell activation by blocking inhibitory signals. Artificial APC-based vaccines: Enhance anti-tumor T cell responses through targeted antigen presentation.