TNFα-treated DC possess enhanced antigen-presenting function. Proliferative responses of purified autologous CD4⁺ T cells to different concentrations of soluble antigens presented by autologous DC were measured at day 6. Non–TNFα-treated or TNFα-treated DC were pulsed with either TT (upper) or CAD (lower), as described in the Materials and Methods. The background cpm of the proliferative response in the absence of antigens pulsed on DC (ie, unpulsed DC plus CD4⁺ T cells or the autologous MLR; upper, +TNFα = 5,236 cpm; −TNFα = 942 cpm; lower, +TNFα = 4,102 cpm, −TNFα = 929 cpm) were subtracted. Experiments were repeated five times with similar results.