Studies of polyarthritis caused by Mycoplasma arthritidis in rats. I. Detection of the persisting Mycoplasma antigen by the enzyme immune assay (EIA) and conventional culture technique.

Investigations on Mycoplasma (M.) arthritidis polyarthritis of the rat produced by intravenous inoculation of M. arthritidis ISR 1 with special reference to the persistence of the inoculated mycoplasma antigen were performed in a total of 145 rats. The mycoplasmas were demonstrated by the conventional culture technique as well as by an enzyme immune assay (EIA). M. arthritidis was cultured from liver, kidney, spleen, and thymus up to 4 days, from trachea and uterus up to 4 weeks, and from lung, heart, brain, and lymph nodes up to 2 months after infection. It could be recovered from the joints in 70-80% of the animals up to 28 days and in the remaining 20-30% up to 200 days after infection. Using the EIA the mycoplasmal antigen could be demonstrated generally, also in the joints of infected rats which had no longer been positive by culture (10-20 weeks after inoculation). The investigations using EIA also showed a positive reaction between antiserum against M. arthritidis and joint homogenates of control rats, indicating the presence of common antigens to M. arthritidis and to joint tissues of the rat.