Immunostimulation of allogeneic T-cell proliferation by mature DCs (mDCs) was impaired by MSC treatment. (A) After MSC treatment, mDCs alone were used in graded doses to stimulate allogeneic CD4+ T cells (*P < .05, **P < .01). ▪ indicates treated DCs; ▴, control cells. (B) Graded doses of treated mDCs were used to stimulate allogeneic CD4+ T cells (1 × 105 cells per well) without MSCs retrieved in the MLR culture (*P < .05, **P < .01). ▴ indicates without MSCs; ▪, with MSCs. (C) Notably, untreated mDCs show clustered and protruding characteristics (top row) in the MLR, while treated mDCs are scattered and round (bottom row) (for both rows, original magnification × 100). Images in panel C were visualized using a Nikon TE2000-U microscope equipped with a Plan Fluor 10×/0.30 objective lens (Nikon). Images were captured and processed as for Figure 1A. (D) After MSC treatment, mDCs loaded with KLH were used in graded doses to stimulate allogeneic CD4+ T cells (*P < .05, **P < .01). Symbols are as in panel A. Thymidine incorporation was measured on day 4 by a 16-hour pulse with 1 μCi 3H-thymidine. (A-B,D) Results are shown as mean ± SD of triplicate values. Cell morphology was determined by phase contrast microscopy. One representative experiment from 3 independent experiments is shown.
