A total of eighty rabbits were immunized with bovine serum albumin or ovalbumin by intradermal injections of antigen-adjuvant emulsion. Level of antibody to the injected antigen was increased about 5 weeks after injection. Intra-articular antigen injections in the knee joints were done to each rabbit by 8 week after first immunization.

An arthritis-score system was established to evaluate the inductivity of knee-arthritis, and such induced signs of inflammation in the joints.

Increase in joint diameter, temperature elevations, erythemas were noted on the knee joint after intra-articular injection. The arthritis-score was higher in ovalbumin-treated group.

Microscopically, the synovial membrane showed hyperplasias, inflammatory cell infiltrations, lymphoid follicle formations and capillary dilatations.