Experimental rheumatoid arthritis-like features induced by prolonged sensitization with focal antigens

Prolonged sensitization with emulsion of an autologous or isologous subcutaneous abscess of Arthus type induced by injection of hen egg-white was performed in 34 rabbits which were divided into (high responder and intermediate responder groups (H- and M-groups) according to individual difference of immune responses. The development of a rheumatoid factor-like substance (RFLS) was demonstrated after 30 experimental days and subsequently observed in 21 out of 33 rabbits. There was no significant difference in the incidence of RFLS between both groups. As to the relation between the development of RFLS and types of focal antigens, the group of the autologous W-substance showed a higher incidence of RFLS than the N-substance. Acute and/or chronic synovitis was demonstrated in 13 of 33 rabbits and inflammatory changes were more intensive and extensive in the later period of experiment. Presence of RFLS in the affected synovial tissues, chiefly in the cytoplasm of plasma cells and mononuclear cells, occasionally in a free state was revealed by immunofluorescent study, and depositions positive for IgG and beta 1C were observed in the wall of blood vessels and fibrinous thrombi in the affected synovial tissues.