Haemophilus influenzae type b polyribosylribitol phosphate conjugated to Neisseria meningitidis outer membrane protein complex (PRP-OMPC)

Haemophilus influenzae type b (Hib) polyribosylribitol phosphate (PRP) conjugated to the outer membrane protein complex (OMPC) of Neisseria meningitidis is a vaccine antigen used to prevent invasive Hib disease (CDC, 2022). The PRP polysaccharide is the primary capsular antigen of the Hib bacterium, but as a T-cell independent antigen, it fails to induce a strong immune response or memory in infants (StatPearls, 2023). By covalently linking the PRP to the OMPC carrier protein, the vaccine converts the polysaccharide into a T-cell dependent antigen (FDA, 2011). This conversion allows for the recruitment of T-helper cells, which stimulate B-cells to produce high-affinity IgG antibodies and establish long-term immunological memory (PubMed, PMID: 2011455). This specific conjugate is highly effective in young children and is a critical component in preventing life-threatening infections such as bacterial meningitis, pneumonia, and epiglottitis (PubMed, PMID: 10951218). Unlike other carriers, the OMPC component is known for inducing a protective antibody response after the first dose in early infancy (NIH, 2023).

Other names

Hib PRP-OMPCPedvaxHIBHaemophilus b conjugate vaccine (Meningococcal Protein Conjugate)PRP-OMP

The PRP-OMPC conjugate functions by presenting the Haemophilus influenzae type b capsular polysaccharide (PRP) to the immune system in a T-cell dependent manner. While pure PRP is a T-cell independent antigen that does not elicit a strong response in infants, its conjugation to the Neisseria meningitidis outer membrane protein complex (OMPC) allows the protein component to be processed and presented by antigen-presenting cells to T-helper cells. These T-cells then provide the necessary co-stimulatory signals to PRP-specific B-cells, inducing their proliferation, class switching to IgG, and the development of long-term immunological memory (PubMed, PMID: 2011455; StatPearls, 2023).