Abstract
Within minutes of CTL-target interaction, the intracellular disintegration of the target cell nucleus begins. This nuclear event satisfies the ionic and temperature requirements that have been described by others as important in CTL-mediated lysis. Such nuclear disintegration does not occur in Ab+C-lysed targets. Thus the target cell nucleus appears to signal a primary event in CTL-mediated lysis that distinguishes the CTL lytic mechanism from that of Ab+C.