Functional analysis of CD8 T regulatory cells.

<p>CD4 T cells were labeled with CFSE and co-cultured with CD8 Treg cells in different ratios (1∶1, 1∶5, 1∶10 and 0∶1; CD8 Treg cells to CD4 T cells) to demonstrate the suppressive function of CD8 Treg cells. After 4 days of co-culturing, proliferation of CD4 T cells was examined by flow cytometer for dilution of CFSE in the FITC channel. (A) Represents proliferation assay from a MM patient. Proliferation of CD4 T cells was inhibited by CD8 Treg cells in a concentration dependent manner but not in their absence, which was clearly shown by the dilution of CFSE. Level of CD4 T cell proliferation in the presence or absence of CD8 Treg cells is represented in percentage. (B) Comparison of MM patients and healthy donors for inhibition of CD4 T cell proliferation mediated by CD8 Treg cells at different concentrations. Mann-Whitney U test showed no significant difference in proliferation assays between MM patients and healthy donors either in the presence or absence of CD8 Treg cells. Median proliferation of CD4 T cells is indicated by horizontal line, small dots and squares represent raw data from each experiment. MM, multiple myeloma; HD, healthy donor; NS, statistically not significant.