Antigen presentation machinery involved in tumor-associated antigen display

The process of immune system activation via tumor-associated antigen presentation is central to anti-tumor immunity. Tumor cells harbor genetic mutations that result in the expression of abnormal, or neoantigenic, proteins. These proteins are processed by the cellular antigen presentation machinery—including proteasomes, peptide transporters (TAP), and major histocompatibility complex (MHC) molecules—and are presented on the cell surface. Antigen-presenting cells (APCs), such as dendritic cells, can also process and present these tumor antigens, crucial for priming cytotoxic T lymphocytes (CTLs). Effective presentation of tumor antigens enables T cells to recognize and eliminate cancer cells. Defects or suppression of these pathways in tumors contribute to immune evasion and resistance to immunotherapies, notably immune checkpoint inhibitors. As such, the antigen presentation pathway is not a druggable target by conventional pharmacological standards but is a key functional aspect leveraged in cancer immunotherapy strategies.

Other names

Tumor antigen processing and presentationTumor-associated antigen presentation pathwayAntigen processing machinery (APM) in cancer

Immune checkpoint inhibitors indirectly enhance antigen presentation by preventing T cell inhibition, allowing effective recognition of tumor-presented antigens. Experimental/Conceptual drugs targeting regulators of antigen processing—such as boosting MHC expression or restoring proteasome/TAP function—could increase tumor visibility to T cells.