The effects of oral D-penicillamine treatment on experimental arthritis and the associated immune response in rabbits.

D-penicillamine given orally to rabbits at a dose of 15 mg/kg body weight, administered daily for long periods commencing prior to and at the time of immunization, reduced the concentration of specific IgG antibodies directed against ovalbumin. This effect was not observed when treatment with the drug commenced after immunization and the onset of a mono-articular arthritis. The concentration of serum IgA rose abruptly after antigen was injected intra-articularly to induce the arthritis. This increase was not affected by treatment with D-penicillamine. The concentration of serum IgA decreased markedly during the chronic phase of the mono-articular arthritis, falling below the lower limit of the normal range. Treatment with D-penicillamine for at least 50 days restored the serum IgA concentration to the middle of the normal range. D-penicillamine treatment had no significant effect on the concentration of IgG, or IgM in serum either before or after the onset of mono-articular arthritis.