Modulation of the susceptibility of inbred and outbred rats to arthritis induced by cell walls of group A streptococci.

Inbred Buffalo rats were resistant to the induction of experimental arthritis induced by systemic injection of cell wall fragments in a crude whole-cell sonic extract of group A streptococci. This was in contrast to the susceptibility of outbred Sprague-Dawley and certain other inbred strains. Preliminary breeding studies indicated that genetic control of resistance of susceptibility is multigenic. When Buffalo rats were infected with a saline suspension of isolated cell wall fragments, chronic remittent arthritis developed. Suspension of isolated cell wall fragments, chronic remittent arthritis developed. Suspension of the isolated cell walls in the supernatant fraction of group A streptococci solubilized by sonication eliminated the arthropathogenicity in Buffalo rats. Thus, a component separable from the cell wall fraction can modulate the arthropathogenicity of cell walls in rats, but the effect depends upon the genetic background of the rat. The antibody response of Buffalo rats to the polysaccharide antigen of cell walls was also affected by the supernatant fraction of sonicated group A streptococci.