Streptolysin O is inactivated by

Streptococci produce 2 types of Streptolysin ( O&S) based on oxygen dependency. Streptolysin O is oxygen labile. It is inactive in the presence of Oxygen. Streptolysin O is antigenic and ASO titre is a standard serological diagnosis of Acute Rheumatic fever. Streptolysin O & S both can cause hemolysis.