Generation and expansion of human CD4+ CD25+ regulatory T cells with indirect allospecificity: Potential reagents to promote donor-specific transplantation tolerance.

Background: Harnessing naturally arising CD4+ CD25+ regulatory T cells (Tregs) for potential adoptive cell therapy is hampered by their innate autoreactivity and their limited number.

Methods: CD4+ CD25+ Tregs were purified from peripheral blood of human leukocyte antigen (HLA) DR1*0101+ A2- individuals, and stimulated with autologous monocyte-derived dendritic cells (DCs).

Results: Here we show that CD4+ CD25+ Tregs specific for an HLA A2 (103-120) peptide can be selected from the peripheral blood CD4+ CD25+ T cell population of a healthy individual and detected using a tetramer comprised of HLA DRB1*0101 and the A2 peptide.