Conditioning followed by autologous bone marrow transplantation leads to a rapid decrease in the severity of arthritis: the clinical effect is reduced by depletion of CD25⁺ cells. (A) The effect of aBMT in PGIA. Arthritis was induced by 2 injections of PG in DDA on day 0 and day 21. On day 35, mice received a lethal irradiation dose of 7.5 Gy followed by autologous BMT from syngeneic donor animals at the same stage of the disease. Mean arthritis scores are shown (+ SEM; N = 17). (B) The effect of anti-CD25 treatment after aBMT. Following aBMT on day 35, the anti-CD25 mAb PC61 was administered on day 35 and day 42 at 2 different doses: 250 μg (N = 2) or 200 μg (N = 6). Mean arthritis scores are shown (+ SEM).