Fig. 4.

Paracrine effect. A. Transwell experiment (TW) were performed where BM-MSC or CMPC are located in the bottom part and activated T cells on top of the 0.4 μm TW-filter. In control groups the cells were allowed cell-cell contact. A. Stimulated T cell co-cultures with BM-MSC and CMPC (TW −) and without (TW +) direct cell-cell contact. Suppression of proliferation occurs in cell contact groups (BM-MSC: 39 ± 17%, n.s., CMPC: 42 ± 16%, p < 0.05). Reduction of proliferation still occurs in the absence of direct cell-cell interactions (BM-MSC: 58 ± 10%, CMPC: 62 ± 9%, p < 0.05 for both) (n = 5). A. Stimulated T cells grown in the presence of CM from BM-MSC or the BM-MSC-T cell co-culture have a significantly reduced proliferation (40 ± 10% (n = 3) and 51 ± 10% (n = 7), respectively), whereas CM from stimulated T cell has no effect (14 ± 17% increase). B. Stimulated T cells proliferate significantly less after addition of CM from CMPC (97 ± 0.2%, p < 0.0001) or the CMPC-T cell co-culture (97 ± 0.3%). ***p < 0.001, **p < 0.01 and *p < 0.05.