CLL cell proliferation is enhanced when exposed to Plexin-B1 transfectants (MLP/Plex-B1)
| Day . | CLL cells alone . | + MLP . | + MLP/Plex-B1* . | + MLP/Plex-B1 + sCD100† . | + CD40L . | + MLP + CD40L . | + MLP/Plex-B1 + CD40L . |
|---|---|---|---|---|---|---|---|
| 1 | 0.8 (± 0.3) | 3.3 (± 0.7) | 7.0 (± 0.4) | 1 (± 0.2) | 1.8 (± 0.5) | 4.2 (± 0.7) | 8.0 (± 0.6) |
| 2 | 0.5 (± 0.2) | 3.1 (± 0.5) | 6.7 (± 0.5) | 1.3 (± 0.3) | 1.9 (± 0.3) | 4.3 (± 0.5) | 8.1 (± 0.6) |
| 3 | 0.2 (± 0.1) | 3.1 (± 0.3) | 6.9 (± 0.5) | 1.2 (± 0.2) | 2.0 (± 0.3) | 4.3 (± 0.6) | 8.0 (± 0.5) |
| 4 | 0.2 (± 0.2) | 3.3 (± 0.1) | 7.0 (± 0.6) | 1.1 (± 0.7) | 2.1 (± 0.1) | 4.2 (± 0.4) | 7.5 (± 0.4) |
| Day . | CLL cells alone . | + MLP . | + MLP/Plex-B1* . | + MLP/Plex-B1 + sCD100† . | + CD40L . | + MLP + CD40L . | + MLP/Plex-B1 + CD40L . |
|---|---|---|---|---|---|---|---|
| 1 | 0.8 (± 0.3) | 3.3 (± 0.7) | 7.0 (± 0.4) | 1 (± 0.2) | 1.8 (± 0.5) | 4.2 (± 0.7) | 8.0 (± 0.6) |
| 2 | 0.5 (± 0.2) | 3.1 (± 0.5) | 6.7 (± 0.5) | 1.3 (± 0.3) | 1.9 (± 0.3) | 4.3 (± 0.5) | 8.1 (± 0.6) |
| 3 | 0.2 (± 0.1) | 3.1 (± 0.3) | 6.9 (± 0.5) | 1.2 (± 0.2) | 2.0 (± 0.3) | 4.3 (± 0.6) | 8.0 (± 0.5) |
| 4 | 0.2 (± 0.2) | 3.3 (± 0.1) | 7.0 (± 0.6) | 1.1 (± 0.7) | 2.1 (± 0.1) | 4.2 (± 0.4) | 7.5 (± 0.4) |
Leukemic cells significantly enhanced their proliferative activity when exposed to Plexin-B1 transfectants (MLP/Plex-B1) in comparison with MLP wild type (*P < .01). The effect on proliferation was significantly abolished by soluble CD100 (MLP/Plex-B1 or stromal cells + sCD100; †P < .05). The coculture experiments were performed also in the presence of soluble CD40L (MLP or MLP/Plex-B1 + CD40L). Proliferation activity was measured by the evaluation of DNA content after PI staining. The numbers express the percentage of CLL cells in S, G2, M phases of the cell cycle and represent the mean values ± standard deviations obtained in 12 independent experiments.