Strain and sex variation in the susceptibility to streptococcal cell wall-induced polyarthritis in the rat.

Sixteen inbred rat strains were examined for susceptibility and resistance to group A streptococcal cell wall-induced polyarthritis. The findings indicated that 2 or more genetic loci, as well as sex-related factors, played a major role in determining susceptibility to arthritis in this model. Breeding studies demonstrated that susceptibility was a dominant or codominant trait. A positive association between the severity of arthritis and the development of chronic inflammation in multiple tissues was also observed. In strains that were relatively resistant to arthritis, chronic inflammation was generally limited to the spleen. Since translocation of the poorly degradable and phlogogenic streptococcal cell walls to the synovium and other tissues appears to initiate inflammation, these studies suggested that susceptibility might be the result of a defect in host mechanisms limiting cell wall dissemination.