PhtD_pep19

PhtD_pep19 is a synthetic peptide vaccine candidate derived from the pneumococcal histidine triad protein D (PhtD) of *Streptococcus pneumoniae*. It represents an immunodominant B-cell epitope located within the zinc-binding domain of the PhtD protein. In preclinical studies, PhtD_pep19 has demonstrated the ability to elicit high-avidity antibodies with significant opsonophagocytic killing activity (OPKA) against multiple pneumococcal serotypes, including 1, 3, and 19A. Immunization with this peptide, either alone or as part of a mixture, has been shown to protect murine models against lethal sepsis caused by highly virulent pneumococcal strains. The peptide is being investigated as a novel immunoreactive component for the development of next-generation, polysaccharide-independent pneumococcal vaccines.