Carcinoembryonic antigen peptide–major histocompatibility complex class I complex

A Carcinoembryonic antigen peptide–major histocompatibility complex class I complex is a molecular structure found on the surface of cells, typically tumor cells, composed of an eight- to ten-amino acid peptide fragment derived from carcinoembryonic antigen (CEA) bound in the peptide-binding groove of a major histocompatibility complex (MHC) class I molecule. This complex is presented on the cell surface and can be specifically recognized by cytotoxic CD8+ T lymphocytes. The efficient formation and surface display of the CEA peptide–MHC class I complex are critical for immune detection and destruction of tumor cells expressing CEA. This molecular complex is the key target of T cell–based immunotherapies and certain cancer vaccines, with its presence serving as both a biomarker of potential therapeutic response and a critical node for immune-mediated tumor cell death. The use of such complexes in therapy is often limited by HLA restriction, the need for sufficient peptide processing and presentation, and potential immunotoxicity to normal tissues expressing CEA at low levels.

Other names

CEA peptide–MHC class I complexPeptide–MHC class I complex (when the peptide is from carcinoembryonic antigen)

Recognition by CD8+ cytotoxic T cells: TCRs on cytotoxic T cells specifically bind to the CEA peptide–MHC class I complex, leading to targeted killing of CEA-expressing cells Immune activation: Triggers targeted cytotoxic T cell responses upon recognition of tumor-derived antigens Antibody binding: TCR-mimic antibodies can bind to these peptide–MHC complexes and mediate cell killing or diagnostic functions