Identification of a human CD8 super(+) regulatory T cell subset that mediates suppression through the chemokine CC chemokine ligand 4

Regulatory T cells (Treg) comprise multiple subsets and are important in controlling immunity and inflammation. However, the induction and mode of action of the various distinct Treg subsets remain ill defined, particularly in humans. Here, we describe a human CD8 super(+)lymphocyte activation gene-3 (LAG-3) super(+)CD25 super(+)FoxP3 super(+) Treg subset, which suppresses T cells partly through the secretion of CC chemokine ligand 4 (CCL4), which can inhibit T cell activation by interfering with T cell receptor signaling. CD8 super(+) Tregs are expanded by antigen in in vivo-primed donors, and can be detected in pathogen-infected human tissue. This CD8 super(+)LAG-3 super(+)CD25 super(+)FoxP3 super(+)CCL4 super(+) Treg subset thus may play a role in immunoregulation in humans, including infectious diseases.