Increase in EBV-specific CTL precursors after two infusions of CTL in a patient with relapsed Hodgkin's disease (—). CTL precursor frequencies (per 10⁶ PBMC) were measured immediately before and for as long as 49 days after the infusion of the T cell lines. Frequency of precursors specific for autologous LCL increased by 10-fold. However, proportion of precursors able to kill allogeneic LCL changed only minimally, indicating that the observed increment in cytotoxicity was due to activity of “classical” CTL, rather than to MHC-unrestricted killer cells (---).