Antigen processing: where tumor-specific T-cell responses begin

It is well established that tumor-specific CD8+ T cells have the capacity to prevent and cure malignancies in animals under experimental conditions. This has raised expectations that it will prove possible to achieve similar successes with human cancers. CD8+ T cells recognize peptides of 8-10 residues derived from cytosolic proteins that are bound to the class I molecules of the major histocompatibility complex. To most effectively manipulate the T-cell response to tumor cells, it is essential to understand the means by which the peptide-class I complex is created in cells. An overview of this process is provided with an emphasis toward the recent findings made by our laboratory.