Inducible Costimulator Gene-Transduced Bone Marrow-Derived Mesenchymal Stem Cells Attenuate the Severity of Acute Graft-Versus-Host Disease in Mouse Models.

In murine allogeneic transplantation models, ICOS gene-transduced bone marrow-derived mesenchymal stem cells (MSCsICOS-EGFP) were evaluated for their effects on GvHD severity and long-term survival. Lethally irradiated BALB/c or first filial generation of BALB/c and C57BL/6 (CB6F1) mice were transplanted with bone marrow cells and splenocytes from C57BL/6 mice to establish acute GvHD models. Recipient mice were injected with MSCsICOS-EGFP, MSCs, MSCsEGFP, ICOS-Ig fusion protein, MSCs + ICOS-Ig, or PBS (control group). Long-term survival, GvHD rates and severity, CD4+ T-cell apoptosis and proliferation, and Th1/Th2/ Th17 effecter cell polarization were evaluated. In the C57BL/6 → CB6F1 HSCT model, the long-term survival in the MSCICOS-EGFP group was higher than that in the GvHD group (74.29 ± 7.39% vs. 0, p < 0.01), and this survival rate was also higher than that in the MSC, ICOS-Ig, or MSC + ICOS-Ig groups (42.86 ± 8.36%, p = 0.004; 48.57 ± 8.45%, p = 0.03; or 50.43 ± 8.45% p = 0.04, respectively). The s...