Suppression of collagen-induced arthritis (CIA) in mice after adoptive transfer of cells from RORγt Tg mice. (A) Severity scores of arthritis. Total draining lymph-node cells were harvested from C57BL/6 mice and RORγt Tg mice at day 10 post first type II collagen (CII) immunization, and 1 × 107 cells were injected into C57BL/6 mice intravenously at day 10 post first CII immunization. Recipient mice were also immunized with CII in complete Freund’s adjuvant (CFA) intradermally on day 11 after the cell transfer. (B) CD4+ cells were isolated from draining lymph nodes of C57BL/6 mice and RORγt Tg mice at day 10 post first CII immunization, and 2 × 106 cells were injected intravenously into C57BL/6 mice at day 10 post first CII immunization, followed by induction of CIA using the method described for A. Data are representative of two independent experiments with similar results, and are mean ± standard error of the mean. *P < 0.05, Student’s t-test.