Inhibition of follicular T-helper cells by CD8+ regulatory T cells is essential for self tolerance

Analysis of the immune system has defined a subset of CD4+ T cells, termed CD4+ Treg, that can inhibit excessive inflammatory immune responses. However, no T cells genetically programmed to inhibit autoantibody formation and systemic-lupus-erythematosus-like disease have so far been defined. A mechanism fitting that description has now been identified in mice. A subset of CD8+ T cells (CD8+ Treg) is shown to prevent autoantibody formation and maintain self-tolerance in a process that involves recognition of Qa-1 peptide ligands expressed at the surface of follicular helper T cells. A detailed understanding of this aspect of immune-system regulation could lead to new approaches for the treatment of systemic lupus erythematosus and other autoimmune disorders.