IL17A and arthritic joint disease: Furthermore, although RORγt expression and IL-17 production in type II collagen (CII)-reactive CD4+ T cells were significantly higher in RORγt Tg mice, arthritis was significantly attenuated in C57BL/6 mice recipients of cells from immunized RORγt Tg mice in adoptive transfer of draining lymph node (LN) cells or recipients of CD4+ cells.