The usability of the MRL/1 mouse strain in detection of anti-rheumatic drugs.

D-Penicillamine (5 mg/kg), prednisolone (0.5 mg/kg), tolfenamic acid and thiabendazole (10 mg/kg) were chronically administered to male and female mice of MRL/1 strain. The treatment was started either at 4 weeks of age (prophylactic dosing) or at 12 weeks of age (therapeutic dosing) and continued until the termination at 24 weeks of age. In male mice all the drugs caused a significant retardation in IgM-RF formation with one of the dosing regimes. D-Penicillamine and prednisolone also had an inhibitory effect on lymph node enlargement. In female mice, however, only thiabendazole retarded the RF activity significantly. None of the drugs had any marked effect on anti-ssDNA antibody formation, and none of the treatments affected the development of renal disease or modified the survival of these mice.