Interleukin 35 (IL-35) is an IL-12 family cytokine which is expressed in regulatory but not effector T cells. It is a dimer composed of IL-12α and IL-27β chains, encoded by two separate genes. Knock-out mice for either of these two genes (Ebi3 and IL12a, respectively) show no overt autoimmunity, but IL-12α and IL-27β knockout T regulatory cells are unable to suppress effectively in vitro or in an inflammatory bowel disease model. The Ebi3 gene also seems to be a direct target of the transcription factor Foxp3.

References

• Collison, LW et al. Nature, Vol 450, pp566-569, doi:10.1038/nature06306