Clostridioides difficile polysaccharide II antigen (PSII)

Clostridioides difficile polysaccharide II antigen (PSII) is a phosphorylated hexasaccharide repeat cell wall glycopolymer that is highly conserved and abundantly expressed on the surface of essentially all clinical C. difficile strains. PSII serves as a scaffold for the anchoring of multiple surface proteins via CWB2 motifs, plays a critical role in bacterial viability and morphology, and functions as an immunodominant antigen for vaccine development. Disruption of PSII anchoring impairs cell wall synthesis and bacterial survival; PSII-based conjugate vaccines elicit protective antibody responses in animal models, highlighting its value as a candidate target for combatting C. difficile infection.

Other names

PSIIC. difficile PSII polysaccharideClostridium difficile PSII antigen

Vaccine mechanism: Induction of anti-PSII antibodies, which recognize C. difficile and neutralize or facilitate immune clearance of the organism. Immune modulation: Conjugated PSII triggers T-dependent antibody responses, improving immune targeting of bacteria.