Staphylococcus aureus type 5 capsular polysaccharide and Staphylococcus aureus type 8 capsular polysaccharide (CP5 (for type 5 capsular polysaccharide), CP8 (for type 8 capsular polysaccharide))

The Staphylococcus aureus type 5 and type 8 capsular polysaccharides (CP5 and CP8) are large surface glycopolymers that envelope most S. aureus isolates and are key virulence factors in the pathogenesis of infection[1][5][7]. Structurally, CP5 and CP8 are closely related polymers that differ in the arrangement and O-acetylation of their sugar residues, but are serologically distinct[4][7]. The capsule inhibits phagocytosis and other host innate immune responses, facilitating bacterial survival during infection and promoting abscess formation[6][8]. Most S. aureus clinical isolates produce either type 5 or type 8 capsule, making both antigens primary targets for vaccine development and for passive immunotherapy using monoclonal or polyclonal antibodies[2][7]. CP5 and CP8 synthesis is encoded by cap gene clusters and is finely regulated in response to environmental and genetic signals[5]. These capsular polysaccharides are not essential for bacterial growth in vitro but are critical for evasion of host immunity in vivo. Strategies targeting CP5 and CP8 aim to enhance opsonic antibody formation and thereby restore the capacity of host phagocytes to clear the pathogen[7][8].

Other names

S. aureus CP5S. aureus CP8type 5 capsular polysaccharidetype 8 capsular polysaccharidestaphylococcal capsuleS. aureus capsule

Induction of anti-capsular antibodies (active or passive immunization) to promote opsonization and phagocytic clearance; Enhancement of neutrophil-mediated killing in the presence of anti-CP5 or anti-CP8 antibodies