Are CD8 super(+)CD122 super(+) cells regulatory T cells or memory T cells?

We identified CD8 super(+)CD122 super(+) regulatory T cells in the mouse. Some immunologists consider CD8 super(+)CD122 super(+) cells to be memory T cells despite our report of their regulatory function. Here, we propose a dual phenotype of these cells. Murine CD8 super(+)CD122 super(+) T cells demonstrate both memory and regulatory features in their functional profiles. Human CD8 super(+)CXCR3 super(+) T cells, which are thought to be the human counterpart of murine CD8 super(+)CD122 super(+) regulatory T cells, do not match human central memory T cells of the CD8 super(+)CD45RA super(-)CCR7 super(+) phenotype. Thus, we must consider human CD8 super(+) regulatory T cells and murine CD8 super(+) regulatory T cells separately. Of human CD8 super(+) regulatory T cells, CD8 super(+)CXCR3 super(+) regulatory T cells can be divided into further subsets and we may be able to distinguish memory T cells and regulatory T cells. Of murine CD8 super(+)CD122 super(+) regulatory T cells, it seems to be impossible to divide CD8 super(+)CD122 super(+)CD44 super(+)CD62L super(+) regulatory T cells into further subsets at present, indicating that this single population of cells has activities of both regulatory T cells and memory T cells.