CD4 and Autoimmunity: This led us to examine the role of another regulatory cytokine, IL-35, which has been shown to inhibit autoimmunity by suppressing inflammatory Th17 activation in murine studies.25,35,43,44 We show IL-35 heterodimer was expressed in human tonsillar CD4+ T cell without stimulation and its expression was significantly downregulated upon SAg-Sau stimulation.