Fig. 2.

Two CD4 clones were cultured as in Fig. 1. CPD cumulative PD. Clone 402-16 is a typical clone which continued to secrete autocrine TNF-α throughout its lifespan, whereas 401-2 is a rare clone which spontaneously lost the ability to secrete TNF-α at ca. 35 PD. Both clones were cultured in the presence or absence of a saturating concentration of neutralising TNF-α antiserum from 35 PD (added weekly at each subculture)