Veto Function in Vitro and in Vivo

Abstract

A CTL_P recognizing another cell, called veto cell, is suppressed by that veto cell. The veto cell can itself be a CTL. For the veto function, the TCR of the veto cell is not required, hence the veto function is a backward action of CTL. Since, from the point of view of the veto cell, only self-reactive CTL_P are suppressed, the veto function could be a mechanism for maintaining self tolerance of CTL. The characteristics of veto function in vitro and in vivo are discussed, as well as the potential physiological relevance.

Key Words:

• mechanism of inhibition
• class I-class II incompatibility
• transplantation tolerance
• self-reactive CTL