🦠microbiology review

Pneumolysin O

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Pneumolysin O is a toxin produced by Streptococcus pneumoniae that can damage host cell membranes and disrupt immune responses. It plays a crucial role in the pathogenesis of pneumococcal diseases.

5 Must Know Facts For Your Next Test

  1. Pneumolysin O is a pore-forming toxin that inserts into host cell membranes causing cell lysis.
  2. It can inhibit the function of phagocytes, aiding in bacterial evasion from the immune system.
  3. Pneumolysin O activates the classical complement pathway, contributing to inflammation and tissue damage.
  4. The presence of Pneumolysin O is a key virulence factor in pneumococcal pneumonia and other related infections.
  5. Vaccines targeting Pneumolysin O are being researched for their potential to prevent pneumococcal infections.

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