This patent covers the use of mesenchymal stem cells to generate T suppressor cells in general. Specifically it mentions that CD8 positive T cells can be turned into suppressor cells by contact with mesenchymal stem cells.
Usually, T suppressor cells are called T regulatory cells and this refers to CD4+ CD25+ cells. CD8+ T suppressor cells were very popular in the 1970s and 1980s but then fell out of favor when results with these cells could not be reproduced. This patent may indicate that indeed there was something to the whole CD8 suppressor T cells story !