Streptococcus pneumoniae polyhistidine triad protein D (PhtD) (PhtD)

Streptococcus pneumoniae polyhistidine triad protein D (PhtD) is a surface-exposed protein that plays a vital role in the pathogen's survival and virulence. It belongs to the polyhistidine triad family, defined by conserved HxxHxH motifs that bind divalent metal ions, specifically zinc, which is essential for bacterial metabolism and gene regulation (UniProt: Q97NK5; PMID: 22438799). PhtD facilitates the attachment of the bacteria to host epithelial cells and contributes to immune evasion by interfering with the complement system, specifically by inhibiting C3b deposition (PMID: 21239449). Due to its high conservation across diverse pneumococcal serotypes, PhtD has been extensively researched as a candidate for serotype-independent protein-based vaccines (PMID: 24583008). These vaccines aim to induce protective antibodies that enhance opsonophagocytosis and prevent bacterial colonization, addressing the limitations of current polysaccharide-conjugate vaccines (PMID: 23434456). Clinical trials have evaluated PhtD-containing formulations, demonstrating their potential to provide broad protection against invasive pneumococcal disease and mucosal infections (PMID: 25214436).

Other names

Pneumococcal histidine triad protein DPhtDSurface protein PhtD

Induction of antigen-specific antibodies that promote opsonophagocytosis and neutralize the protein's role in bacterial adhesion and immune evasion.