Susceptibility and resistance to 6-sulfanilamidoindazole-induced arthritis among inbred strains of rats.

Inflammation induced by 6- sulfanilamidoindazole (6-SAI) in aged, outbred rats is predictably produced, but the pathogenesis is not understood. We demonstrate the variable resistance of 15 inbred rat strains to 6-SAI arthritis. Susceptibility to 6-SAI arthritis is not directly linked to the major histocompatibility complex, although resistance is related to the major histocompatibility complex in other experimental forms of rat arthritis. The genetic background of these inbred rat strains appears to have a major role in 6-SAI arthritis susceptibility.