Haemophilus influenzae type b capsular polysaccharide (PRP)

The Haemophilus influenzae type b (Hib) capsular polysaccharide is a high-molecular-weight polymer composed of repeating units of polyribosyl-ribitol-phosphate (PRP). It forms the outermost structure of encapsulated Hib bacteria and is a critical virulence factor, enabling the bacterium to evade host immune responses. When conjugated to a carrier protein it is a key component of current Hib vaccines, inducing robust antibody responses that confer protection against invasive Hib disease.

Other names

Hib capsular polysaccharidePolyribosyl-ribitol-phosphatePRP

Antibodies generated against PRP (when conjugated to a carrier protein) neutralize the polysaccharide, preventing Hib from evading the immune system and causing disease. Glycoconjugate vaccines elicit an immune response against the PRP.