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

•CD8+CD44+Ly49+ T regulatory cells were induced by CD4+ T cells which were activated by MHC class II-restricted peptide.•CD8+CD44+Ly49+ T regulatory cells have a cross-suppressive activity on responding CD4+T cell.•CD8+CD44+Ly49+ T regulatory cells suppress the proliferation and activation of responding CD4+ T cell in a cytotoxicity-dependent manner.

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.