Characteristics of polyarthritis in rabbits by hyperimmunization with attenuated Enterococcus faecalis

To produce polyarthritis and rheumatoid factor like substance (RFLS), rabbi ts were hyperimmunized intravenously with 0.02% thimelosal (TMS)-treated En terococcus faecalis (E. faecalis) as a persistent bacterial flora. Swelling of knee joints occurred at a rate of 41% (27/66), and of shoulder joints a t a rate of 25% (17/66) while that of elbow joints occurred at a rate of 4. 5% (3/66). On culturing of knee joint fluids, no colonies appeared while 2/ 4 fluid specimens from the shoulder joints gave positive colonies for 78 da ys after the first immunization; thereafter, no colonies appeared. On histo logical examination, in early stages, acute inflammatory reactions with deg enerative changes of synovial tissue was observed. In later stages, chronic inflammatory changes, proliferation of synovial cells with pannus formatio n, destruction of articular cartilage and subchondral bone were observed. R FLS titer showed bi-phasic peaks at 11 days and 41 days after the first imm unization. A high incidence of polyarthritis, particularly knee joints, occ urred. Thus, hyperimmunization with attenuated E. faecalis as a normal inte stinal flora may provide an animal model of chronic polyarthritis.