FIG. 3.

Effect of BALB/c MSCs, unmodified or transduced to express CTLA4Ig, on cytokine secretion by stimulated DBA/1 CD4+ T cells. CD4+ DBA/1 T cells were isolated, stimulated with anti-CD3 and CD28 beads, and cocultured with BALB/c MSCs, MSCs Adnull or MSC AdCTLA4Ig at a ratio of 1:10 or 1:1 (MSC:T cells). Supernatants were collected at 24 and 72 h for cytokine analysis and T cells stimulated in the absence of MSCs served as controls. (A) At both 24 and 72 h, there was significant suppression of TNFα secretion by T cells cultured with MSCs compared to controls; this was independent of viral modification. (B) A decrease in IFNγ production was also noted. This was seen in all groups but was most notable at a ratio of 1:10 after 72 h incubation. At the ratio of 1:1 only MSCs transduced with CTLA4Ig reduced IFNγ production. (C) IL-4 secretion by DBA/1 CD4+ T cells was initially suppressed by MSCs at a ratio of 1:10; however, at 72 h and at a ratio of 1:1 there was a significant augmentation in IL-4 production. All 1:1 MSC groups secreted elevated levels of IL-4 compared to non MSC controls; however, the MSCAdCTLA4Ig group secreted significantly less IL-4 than the other two MSC groups at this timepoint. (D), MSCs had a transient effect on IL-10 production at 24 h, which was not sustained at 72 h. All experiments were carried out three times and assayed in triplicate, *P<0.05, **P<0.01 (two-way ANOVA). Data represents mean±SD.