The present invention relates to regulatory T cell and uses thereof. By their immunosuppressive and anti-inflammatory activities, regulatory T cells play a central role in peripheral tolerance and thus critically prevent the development of autoimmune and inflammatory disorders. The inventors showed that Foxp3+CD4+ Tregs express high levels of LTα, which negatively regulates their immunosuppressive signature. They demonstrated that the adoptive transfer of LTα-/- Tregs in mice protects from dextran sodium sulfate (DSS)-induced colitis and attenuates inflammatory bowel disease (IBD), multi-organ autoimmunity and the development of CAC. The inventors also showed that by mixed bone marrow chimeras that LTα expression specifically in hematopoietic cells negatively controls the immunosuppressive signature of Tregs. In particular, the present invention relates to regulatory T cell characterized in that it does not express or expresses reduced levels of lymphotoxin alpha.