Haemophilus influenzae type b capsular polyribosyl-ribitol phosphate (PRP) (PRP)

Haemophilus influenzae type b capsular polyribosyl-ribitol phosphate (PRP) is a linear polymer consisting of ribose, ribitol, and phosphate, which serves as the primary virulence factor for the Hib bacterium (CDC, 2022). This polysaccharide capsule allows the pathogen to evade the host's innate immune system by resisting phagocytosis and complement-mediated killing, thereby facilitating systemic spread (StatPearls, 2023). PRP is the central component of Hib vaccines, where it is typically conjugated to a carrier protein to convert the T-cell independent carbohydrate antigen into a T-cell dependent antigen, ensuring long-term immunological memory and efficacy in infants (WHO, 2013). Therapeutic intervention primarily involves the administration of these conjugate vaccines to induce protective anti-PRP antibodies that neutralize the bacteria (PubMed, 2021). Monitoring of anti-PRP IgG levels is the standard biomarker for assessing vaccine-induced protection (NIH, 2020). The widespread use of PRP-based vaccines has led to a dramatic reduction in the incidence of invasive Hib diseases such as meningitis and epiglottitis (Journal of Pediatrics, 2019).

Other names

Polyribosyl-ribitol phosphateHib PRPHib capsular polysaccharidePoly(ribosylribitol phosphate)

Induction of serum IgG antibodies against the PRP capsule, which facilitate opsonization, phagocytosis, and complement-mediated lysis of the bacteria.