streptolizinok

Streptolysin O is a potent exotoxin produced by certain strains of Streptococcus pyogenes, a bacterium also known as group A Streptococcus. This toxin is a key virulence factor, contributing significantly to the pathogenesis of streptococcal infections. It belongs to the thiol-activated cytolysin family, meaning its activity is dependent on the presence of reducing agents and it can be inhibited by cholesterol.

The primary action of streptolysin O is to form pores in the cell membranes of eukaryotic cells, leading to cell lysis. This damage affects various cell types, including red blood cells, white blood cells, and platelets. The release of cellular contents can trigger inflammatory responses and contribute to tissue damage. Streptolysin O is also known to suppress immune cell function, further aiding the bacteria in evading host defenses.

Due to its ability to lyse red blood cells, streptolysin O is a hemolysin. Its detection in patient serum is a significant diagnostic marker for recent Streptococcus pyogenes infection. Antibodies against streptolysin O, specifically anti-streptolysin O (ASO) titers, are commonly measured to confirm exposure to group A Streptococcus. Elevated ASO titers can indicate conditions such as rheumatic fever or post-streptococcal glomerulonephritis, which are post-infectious complications. Vaccines targeting streptolysin O are under development as a potential strategy to prevent these sequelae.