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-CD
3-induced apoptosis. Induction of CTL in the presence of antisense TNF
oligodeoxynucleotides inhibits TNF secretion and cell death after sti
mulation 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.