Question

Please explain what the polysaccharide capsule is in Streptococcus pneumoniae. What does it do?

Thank you

Answer 1

The polysaccaride capsule of Streptococcus pneumoniae is a virulence factor. The presence of the polysaccharide capsule is responsible for protection against phagocytosis. immunity as a result of compliment system and killing due to opsonophagocytic system. The capsule is also responsible for preventing the capture of Streptococcus pneumoniae by neutrophil extracellular traps. Entrapment of Streptococcus pneumoniae in the airway mucus is prevented by the capsule and it also prevents mucus mediated clearance. The capulse also dampens the effect of innate immnunity.