Within the tumour necrosis factor (TNF) family the induction of apoptosis i
s restricted to some ligand-receptors pairs, including TNF-TNF receptor typ
e I (TNFRI/p55). FasL-Fas, TNF-related apoptosis-inducing ligand (TRAIL) an
d its death-receptors (DR)-4 and -5, The pair CD40L-CD40 belongs to the sam
e family but rescues B cells from apoptosis. To investigate how these oppos
ing actions are cross-linked, purified follicular lymphoma (FL) cells were
activated upon a human CD40L-transfected murine fibroblastic layer, then RN
A messengers for the above molecules were analysed using RT-PCR, The observ
ed down-modulation of TRAIL and up-regulation of TNF and Fas transcripts mi
ght account for CD40-CD40L-mediated FL cell survival.