Comparison of the effects of various arthritis therapies on disease severity in rats with established adjuvant-induced arthritic (AIA). Rats were left either unimmunized or immunized with keyhole limpet hemocyanine-fluorescein isothiocyanate (KLH-FITC) in an equal volume of alum adjuvant to generate a high anti-FITC antibody titer. AIA was induced by the base-of-tail method, and 7 days after induction each therapy was initiated. The therapies were folate-FITC in non-immunized rats (folate-FITC; 30 nmole/kg per day, i.p.), non-targeted aminofluorescein (AF) in immunized rats (KLH-FITC + AF; 30 nmole/kg per day, i.p.), clodronate liposomes (CL; 3.6 mg/kg on days 8, 16, and 23, i.p.), celecoxib (20 mg/kg every other day, oral gavage), etanercept (4 mg/kg per day, i.p), anakinra (120 mg/kg per day, continuous infusion, Alzet osmotic pump), methotrexate (MTX; 0.75 mg/kg per week, i.p.), or folate-targeted immunotherapy (FTI) in immunized rats (KLH-FITC + folate-FITC [FTI]; 30 nmole/kg per day, i.p.). All groups were measured for arthritis symptoms by monitoring changes in ankle diameter (a), bone and cartilage degradation (b), uptake of EC20 in the spleen and liver (c), and splenomegaly (d). Data are representative of two independent experiments (mean ± standard deviation, n = 5 rats/group).