[The functions of CD4+CD25-LAG3+ regulatory T cells and Egr2 in the regulation of autoimmunity].

Regulatory T cells (Treg) are important mechanisms that regulate autoimmunity and CD4+CD25+Foxp3+ regulatory T cells (CD25+Treg) have been extensively investigated. Recently, we have identified CD4+CD25-LAG3+ regulatory T cells (LAG3+Treg) that express an anergy associated transcription factor Egr2. Egr2 regulates IL-10 production in response to IL-27, and Egr2-deficiency in T cells and B cells results in systemic autoimmunity with increased IL-17 production. Moreover, addition of Egr3 deficiency to Egr2-deficient mice significantly accelerates systemic autoimmunity without functional impairment of CD25+Treg, indicating cooperative autoimmune-regulation by Egr2 and Egr3. The linkage between Egr2 and systemic autoimmunity is also suggested by the fact that stimulation with Ly108, a candidate lupus susceptibility gene in lupus-prone NZM2410 mice, induces Egr2 expression in T cells. Collectively, LAG3+Treg and Egr2 are the unique regulators of autoimmunity and further examination may help to understand and control immune responses.