MHC class II peptides induce CD8⁺CD44⁺Ly49⁺ regulatory T cells in C57BL/6 mice

CD8⁺ regulatory T cells (Tregs) play an important role in regulating peripheral immune tolerance. However, difficulties in the characterization of CD8⁺ Tregs that lack suitable markers have a considerably limited research in this area. Moreover, the induction and effector mechanisms of CD8⁺ Tregs remain unclear. Herein, we demonstrate the suitability of Ly49 and CD44 as markers for CD8⁺ Tregs. Our data also show that MHC class II restricted peptides induce CD8⁺CD44⁺Ly49⁺ Tregs via CD4⁺ T cell activation. Furthermore, we also found cross-suppressive activity of these CD8⁺ Tregs on responding CD4⁺ T cells in a cytotoxicity dependent manner. Our data provide new insights into the induction and function of CD8⁺ Tregs.