In the above studies, Rorc up-regulation in IL-17+ CD8+ T cells was accompanied by an increase in expression of another ROR subfamily homologue, Rora (encoding retinoic acid receptor-related orphan receptor alpha) plus a reduction in Eomes (encoding Eomesodermin) , , , . Other markers of CD8+ T cell effector cells such as Tbx21 and Gata3 were reduced in these cells with the exception of one study in which CD8+YFP+ cells from IL-17A-YFP+ reporter mice were shown to have notable Tbx21 expression, although this was performed over an extensive time course and may be linked to the plasticity of IL-17+ CD8+ T cells to produce IFN-γ over time . Furthermore, CD8+ T cells from Tbx21 and Eomes double knockout mice have higher IL-17A expression compared to wild type cells . Overall these findings indicate that the absence of Tbx21 and Eomes expression plus up-regulation of Rora and Rorc currently represent a reliable molecular characterisation of IL-17+ CD8+ T cells, at least in mice.