Streptolysin O – key properties Which statement best summarizes the properties of streptolysin O produced by Streptococcus pyogenes?

Introduction / Context:
Streptolysin O (SLO) is a cholesterol-binding cytolysin of Streptococcus pyogenes. Understanding its biochemical features explains lab tests (ASO titer) and clinical effects on tissues.

Given Data / Assumptions:

• We assess antigenicity and lability characteristics.
• SLO is distinct from streptolysin S (SLS), which is oxygen-stable and non-antigenic.

Concept / Approach:

SLO is oxygen-labile and inactivated by heat; it is antigenic, eliciting anti-streptolysin O (ASO) antibodies measurable in post-streptococcal sequelae. Together, these properties distinguish it from SLS.

Step-by-Step Solution:

Verification / Alternative check:

Elevated ASO titers support recent GAS infection in rheumatic fever workups, confirming SLO antigenicity.

Why Other Options Are Wrong:

• Any single property alone is incomplete; SLO has all listed features.
• “None” contradicts established biochemistry.

Common Pitfalls:

• Confusing SLO with SLS; only SLO is strongly antigenic and oxygen-labile.

Final Answer:

All of these