Polyribosyl-ribitol-phosphate (PRP) (PRP)

Polyribosyl-ribitol-phosphate (PRP) is the defining capsular polysaccharide of the bacterium Haemophilus influenzae type b (Hib), a major human pathogen. It consists of a polymer of ribosyl-ribitol-phosphate units and functions as a critical virulence factor by shielding the bacterium from host immune recognition and phagocytosis (Source: PubChem CID 139588977). In the pharmaceutical industry, PRP is the primary target for vaccine development; however, as a polysaccharide, it is a T-cell independent antigen that fails to elicit a robust immune memory in infants. To overcome this, PRP is chemically conjugated to carrier proteins such as tetanus toxoid or meningococcal protein complexes to create conjugate vaccines that induce high-affinity IgG antibodies and long-term protection (Source: CDC Pink Book). These vaccines have effectively eliminated Hib-related meningitis and pneumonia in populations with high vaccination coverage (Source: WHO). Therapeutic monitoring of PRP-based interventions typically involves measuring serum anti-PRP antibody concentrations as a correlate of protection (Source: StatPearls, PMID: 30020600).

Other names

Haemophilus influenzae type b capsular polysaccharideHib polysaccharidePoly(ribosylribitol phosphate)

Induction of opsonophagocytic antibodies (anti-PRP IgG) that facilitate bacterial clearance by the immune system.