TCR cross-linking induces CTL death via internal action of TNF.

TCR-mediated stimulation can result in either activation or apoptosis, raising the question of what the mechanisms of these opposing effects might be. Here we demonstrate that microinjection of Ab specific for TNF inhibits activation-induced cell death, implicating TNF in anti-CD3-induced apoptosis. Induction of CTL in the presence of antisense TNF oligodeoxynucleotides inhibits TNF secretion and cell death after stimulation with anti-CD3. Incubation of cells with IL-2 for 48 h before stimulation protects from anti-CD3-induced death, whereas the presence of IL-2 during anti-CD3 treatment is without effect.