Fig. 2. Distribution of different tetraspanins (CD9, CD81 and CD82), raft markers (LAT) and non-raft molecules (CD71) in sucrose gradients. 2x10⁷ Jurkat cells (A,B) or PHA blasts from healthy donors (C) were lysed at 4°C in MNE buffer supplemented with either 1% BRIJ-58 (A, left) or 0.5% Triton X-100 (A, right, B, C). Lysates were centrifuged overnight at 4°C in a three-step (42.5%, 30%, 5%) sucrose gradient and 12 fractions of 280 µl were collected from the top. An equal amount of each fraction (B,C) or a pool of four sequential fractions (1-4, 5-8, 9-12) (A) was subjected to non-reducing SDS-PAGE and immunoblotting was carried out using antibodies against molecules indicated in the figures.