Streptococcus pneumoniae can escape phagocytic clearance by which mechanism?
- Capsule-mediated inhibition of phagocytosis
- Inhibition of phagolysosome fusion
- Inhibition of opsonization mediated by protein A
- Lysis of phagosome and replication in cytoplasm
- Replication in fused phagolysosome
S. pneumoniae is covered with a complex polysaccharide capsule. This is the major virulence factor for these bacteria because the presence of the capsule prevents phagocytosis. Encapsulated strains are associated with disease in humans and experimental animals, whereas nonencapsulated strains are avirulent. Free capsular polysaccharides can be released from the bacteria and bind opsonic antibodies, further protecting the bacteria from phagocytosis
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