Cyto-Toxic Cells Induced Invitro By Epstein-Barr Virus-Antigens

Lymphocyte blastogenesis and cytotoxicity for lymphoid cells lines (LCL) were induced in cells from immune donors by stimulation in vitro with irradiated Epstein-Barr Virus (EBV). Velocity sedimentation of blastogenic populations indicated that much of the killing was associated with large E-rosetting cells; it was reduced by [ 3 H]thymidine suicide immediately prior to sedimentation. Target cells were killed irrespective of EBV content or sensitivity to natural killer (NK cells), though the pattern of lysis varied with repeated use of individual donors. Up to 9% of the normal resting lymphocytes became blastogenic though fewer than 30% of the dividing cells at termination of culture had undergone more than one division. It is suggested that EBV antigens induce a polyclonal activation of cytotoxic T cells. The possible significance of this response is discussed with particular reference to the origin of non-EBV-specific cytotoxic blast cells in infectious mononucleosis.