Tumor antigen presentation via major histocompatibility complex class I pathway (MHC I antigen presentation pathway)

Tumor antigen presentation via major histocompatibility complex class I pathway is a multi-step cellular process crucial for immune surveillance by cytotoxic CD8+ T cells. Tumor-derived protein fragments are processed, loaded onto MHC I molecules, and displayed on the cell surface, thereby enabling T cell recognition and elimination of malignantly transformed cells. The pathway involves coordinated action of the proteasome (for peptide generation), transporters (TAP1/TAP2 for ER translocation), and a range of chaperones (tapasin, calnexin, calreticulin, ERp57) facilitating folding and loading. Tumor cells often evade immune detection by altering or losing components of this pathway, which undermines both natural and therapeutic immune responses and is a key challenge in cancer immunotherapy.

Other names

MHC I antigen processing and presentation pathwayMHC class I pathwayantigen processing machinery (APM)

Drugs impacting this pathway function through augmentation of tumor cell antigenicity (by restoring/reinforcing MHC I pathway), enhancement of immune checkpoint blockade (increasing CD8+ T cell response to tumor-presented antigens), and reinforcement of peptide generation and loading.