US2 and US11 inhibit MHC class I surface expression in hMSCs of different donors.

<p>(A) Flow cytometric analysis of HLA-ABC surface expression in hMSCs derived from the BM of three different donors. Gray lines represent untransduced hMSCs. Black lines correspond to hMSCs transduced with RV-US2-eGFP (upper panels) or with RV-US11-eGFP (lower panels). The presented data are from cells analyzed 30 days after transduction. (B) Flow cytometric analysis of CD44 surface expression in hMSCs of donor 4 at 30 days after transduction with RV-US2-eGFP (upper panel) or RV-US11-eGFP (lower panel). Similar results were obtained with cells of all other donors (data not shown). (C) Comparison of down-regulation of HLA-ABC surface expression by RV-US2-eGFP and RV-US11-eGFP. Shown are HLA-ABC MFI values of untransduced (gray bars) and transduced (black bars) cells of single samples of culture-expanded hMSCs from 4 donors (marked D1 to D4; values derived from data presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014493#pone-0014493-g001" target="_blank">Fig. 1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014493#pone-0014493-g002" target="_blank">2</a>). The differences in the average MFI ratio (calculated as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014493#pone-0014493-g001" target="_blank">Fig. 1</a>) between the hMSCs exposed to RV-US2-eGFP and those transduced with RV-US11-eGFP is highly significant (*p = 0.0005).