Figure 4. c-IAP1 and c-IAP2 are only partially redundant in T cells.

(A) Purified T cells were cultured in vitro with the indicated amount of anti-CD3 in the absence (left panel) or presence (right panel) of 2 µg/ml of anti-CD28. After 48 hr, cells were pulsed with ³H-thymidine and harvested 18 hr later. The panel represents the average of four independent experiments and the error bars are the SEM. ***p<0.005. (B) Expression of p100 and p52 in purified T cells was detected by immunoblotting. For each sample densitometry of p100 and p52 was performed and the results expressed as the ratio between each protein and β-actin. Expression of NIK (C) and c-IAP1/2 (D) in purified T cells was detected by immunoblotting. Values in C represent the ratio between NIK and β-actin. (E) p100/52 immunoblot of T cells freshly purified or stimulated for 24 hr with 1 µg/ml anti-CD3±2 µg/ml anti-CD28. (F) T cells were stimulated as in (E) and ELISA was performed on supernatants collected after 24 hr. One of two independent experiments is shown and the error bars are the SD of the duplicates. *p<0.05.