Streptolysin is a streptococcal hemolytic exotoxin. Types include streptolysin O (SLO), which is oxygen-labile, and streptolysin S (SLS), which is oxygen-stable. An antibody, antistreptolysin O, can be detected in an antistreptolysin O titre. Streptolysin O is hemolytically active only in a reversibly reduced state, unlike streptolysin S, which is stable in the presence of oxygen. Another difference is that SLO is antigenic, while SLS is not antigenic due to its small size. The main function of streptolysin O is to cause hemolysis (the breaking open of red blood cells) ?in particular, beta-hemolysis. Increased levels of aso titre in the blood could cause damage to the heart and joints. In most cases, penicillin is used to treat patients with increased levels of aso titre. |