Abstract
Following the intravenous injection of live Yersinia enterocolitica O:8, 50-69% of SHR rats developed arthritis; these rats were antibody free against all rat pathogens tested. In contrast, only 20-25% of SHR rats which had serum antibodies against Bacillus piliformis, Kilham rat virus, and Toolan H-1 virus developed arthritis. The results indicate that the microbial load of the host has a profound effect on the susceptibility to experimental arthritis.