CROSS-PRESENTATION - A GENERAL MECHANISM FOR CTL IMMUNITY AND TOLERANCE

MHC class I-restricted presentation is usually associated with the pro cessing of endogenous antigens. However, this restriction element can present antigens that do not originate within the presenting cells. He re, Francis Carbone and colleagues describe how such cross-presentatio n is critical for cytotoxic T-cell surveillance of peripheral antigens , both self and foreign, located outside the secondary lymphoid compar tment.