Final answer:
The lysis of RBCs, platelets, and neutrophils in Group A Strep is caused by the toxins Streptolysin O and Streptolysin S. These hemolysins lead to the destruction of blood cells which helps the bacteria in the evasion of the host's immune system. Option 1 and 2 are correct answer.
Step-by-step explanation:
The lysis of red blood cells (RBCs), platelets, and neutrophils in Group A Streptococcus (Strep) infections is primarily caused by two toxins: Streptolysin O and Streptolysin S. These toxins are hemolysins produced by the bacteria which can damage and lyse these cells. Streptolysin O is an oxygen-sensitive cytotoxin, which means its hemolytic activity is hindered in the presence of oxygen, while Streptolysin S is oxygen-stable and can effectively cause lysis in the presence of oxygen.
Both of these toxins contribute to the ability of Group A Strep to cause disease by destroying cells that are important in the body’s defense mechanisms. The other options listed, Streptokinase and Streptococcal pyrogenic exotoxin, serve different roles: Streptokinase is involved in fibrinolysis, aiding the spread of infection by breaking down clots, and Streptococcal pyrogenic exotoxin is associated with the characteristic rash of scarlet fever and other systemic effects.