Virulence factor

Role in pathogenesis

Ref

Capsule

Prevents opsonophagocytosis

[35] -[37]

Hyaluronidase

Helps in the spread of infection through host tissues

[42] -[44]

Pilus

Mediates attachment of pneumococci to host cells

[38]

IgA protease

Breaks down human IgA1

[54]

Neuraminidase

Exposes pathogen binding sites in host by cleaving sialic acid

[50] [54]

PspA

Causes inhibition of complement activation; binds to lactoferrin

[51] [52]

PspC

Hinders formation of C3b; binds to slgA and factor H

[55] -[57]

Autolysin A

Causes autolysis of pneumococci and release of pneumolysin

[48] [49]

Pneumolysin

Acts as a cytolytic toxin and activates complement

[45] -[47]