M protein

Definition

M protein is a virulence factor found on the surface of certain bacteria, notably Streptococcus pyogenes. It plays a crucial role in evading the host immune response by inhibiting phagocytosis.

5 Must Know Facts For Your Next Test

1. M protein contributes to the pathogenicity of Streptococcus pyogenes by preventing opsonization.
2. The gene encoding M protein is highly variable, leading to numerous serotypes.
3. M protein can bind to fibrinogen and complement regulatory proteins, enhancing bacterial survival.
4. Laboratory detection of M protein can be critical for diagnosing streptococcal infections.
5. Vaccines targeting M protein are being researched as potential preventive measures against streptococcal diseases.

Review Questions

• What role does M protein play in the immune evasion mechanisms of Streptococcus pyogenes?
• How does the variability of the M protein gene influence streptococcal infections?
• Why is detecting M protein important in diagnosing streptococcal infections?

Related terms

Streptococcus pyogenes:

A species of Gram-positive bacteria responsible for many human diseases, including strep throat and necrotizing fasciitis.

Opsonization:

The process by which pathogens are marked for ingestion and elimination by phagocytes.

Phagocytosis:

The process by which cells, such as macrophages, engulf and digest foreign particles or pathogens.