-Most strains of S. pyogenes are covered with a capsule composed of hyaluronic acid (HA) identical to the HA found in host cells, preventing an immune response by the host.
-Two different hemolysins, streptolysin O (SLO) and streptolysin S (SLS), cause damage to leukocytes, liver and heart muscle, whereas erythrogenic toxin produces fever and the bright red rash characteristic of S. pyogenes disease.
-Invasion of the body is aided by several enzymes that digest fibrin clots (streptokinase), connective tissue (hyaluronidase), or DNA (streptodornase).