Pneumococcal histidine triad protein D (PhtD) (PhtD)

Pneumococcal histidine triad protein D (PhtD) is a highly conserved surface-exposed lipoprotein found in Streptococcus pneumoniae (UniProt: P0C0S2). It belongs to the polyhistidine triad (Pht) family, characterized by multiple HxxHxH motifs that facilitate the binding of divalent metal ions, particularly zinc (PubMed: 21690217). PhtD plays a critical role in bacterial survival by mediating zinc acquisition in metal-restricted host environments and contributing to adherence to host epithelial cells. Furthermore, it has been shown to inhibit complement deposition by binding to Complement Factor H, thereby aiding in immune evasion (PubMed: 22438799). Due to its high conservation across various pneumococcal serotypes, PhtD is a prominent candidate for next-generation protein-based vaccines aimed at providing broad protection against pneumococcal diseases such as pneumonia, meningitis, and otitis media (ClinicalTrials.gov: NCT01204697). Therapeutic strategies primarily involve active immunization to elicit opsonophagocytic antibodies that neutralize the protein's function and clear the pathogen.

Other names

PhtDPolyhistidine triad protein DBVH-11SP0361Histidine triad protein D

Induction of antigen-specific antibodies to promote opsonophagocytosis and neutralize bacterial adherence and zinc acquisition.