Haemophilus influenzae type b polyribosylribitol phosphate antigen (PRP)

Polyribosylribitol phosphate (PRP) is the primary capsular polysaccharide of Haemophilus influenzae type b (Hib), a Gram-negative bacterium that causes severe invasive infections such as meningitis and pneumonia (CDC, 2022). PRP serves as a major virulence factor by inhibiting phagocytosis and protecting the bacterium from complement-mediated killing (StatPearls, 2023). As a therapeutic target, PRP is the central component of Hib conjugate vaccines, which are designed to induce protective anti-PRP antibodies (WHO, 2019). Because PRP alone is a T-cell independent antigen, it is chemically linked to carrier proteins to enhance immunogenicity and induce immunological memory in infants (PubMed, PMID: 1275838). These vaccines have significantly reduced the global burden of Hib-related diseases by promoting opsonization and bacterial clearance (NIH, 2021). The success of PRP-targeted immunization programs represents a landmark in public health, nearly eliminating Hib meningitis in regions with high vaccine coverage (CDC, 2022).

Other names

Polyribosylribitol phosphateHib capsular polysaccharidePRP antigenHaemophilus influenzae type b polysaccharideHib PRP

Induction of protective serum IgG antibodies (anti-PRP) that facilitate opsonization, phagocytosis, and complement-mediated lysis of the bacteria (StatPearls, 2023).