Selective impairment of TCR-dependent JNK and p38 activation by NSAIDs. Immunoblot analysis of postnuclear supernatants from Jurkat cells (A-C) or freshly purified human PBLs (D), nonactivated (0) or activated by CD3 (CD3) ligation for 5 minutes, in the presence or absence of 600 μM ibuprofen (ibupr), 15 μM sc-560, 250 μM NS-398, or 1 μg/mL PGE₂. Each filter was sequentially probed by immunoblot with antiphospho–JNK (A,D), antiphospho–p38 (B,D), or antiphospho–Erk (C-D) antibodies and then, after stripping, with control antitubulin, anti-p38, or anti-Erk antibodies as indicated. The migration of molecular mass markers is shown. Anti-P indicates antiphospho; and WB, Western blot.