MHC CLASS-I MOLECULES, THEIR ROLE IN PRESENTING PEPTIDE ANTIGENS, INCLUDING TUMOR-ANTIGENS, TO CYTOTOXIC T-LYMPHOCYTES

Cytotoxic T lymphocytes (CTL) have the capacity to recognize and elimi nate transformed cells. The molecular basis for the presentation of tu mor antigens to CTL has only been revealed fully during the last decad e. Tumor antigens are now known to be of peptidic nature, being derive d from degraded cellular proteins and presented at the cell surface by self major histocompatibility complex (MHC) class I molecules. In the present review, we will describe the events involved in the processin g and presentation of antigens by MHC class I molecules, with particul ar emphasis on tumor antigens and their recognition by CTL.