• Vaccine Name: Nontypeable H. influenzae NucA Protein vaccine
• Target Pathogen: Haemophilus influenzae
• Target Disease: Meningitis
• Vaccine Ontology ID: VO_0004038
• Type: Subunit vaccine
• Status: Research
• Antigen: NucA Protein
• nucA gene engineering:
  • Type: Recombinant protein preparation
  • Description:
  • Detailed Gene Information: Click Here.
• Adjuvant:
  • Adjuvant name:
  • VO adjuvant ID: VO_0001250
  • Description: MPL (3-O-deacylated monophosphoryl lipid A.
• Preparation: The native protein was extracted from NTHi strain P860295 with KSCN and purified. The recombinant protein was cloned, sequenced, and expressed in Escherichia coli. The recombinant protein is localized in the periplasm of E. coli and has been purified to homogeneity. Both the recombinant and native proteins possess 5'-nucleotidase activity (Zagursky et al., 2000).
• Immunization Route: Intraperitoneal injection (i.p.)
• Description: A surface-exposed, highly conserved, immunogenic NTHi protein was identified, which elicits cross-reactive bactericidal antibodies against NTHi (Zagursky et al., 2000). This protein, called NucA, has been identified as a 5' nucleotidase and has been cloned, sequenced, and expressed recombinantly. It elicits broadly cross-reactive antibody against NTHi strains and has vaccine potential.

Mouse Response

• Host Strain: Swiss-Webster mice
• Vaccination Protocol: Swiss-Webster mice were immunized subcutaneously with 5 µg of NucA protein and 50 µg of MPL (3-O-deacylated monophosphoryl lipid A; RIBI ImmunoChem Research, Inc., Hamilton, Mont.) as adjuvant per dose at weeks 0, 4, and 6. Blood samples were collected at weeks 0 and 10 for analyses of antibody titers to protein, whole cells, and bactericidal activity (Zagursky et al., 2000).
• Efficacy: Mouse antiserum generated against the purified protein was reactive on whole-cell enzyme-linked immunosorbent assay (ELISA) with seven NTHi strains and type b Eagan and Whittier strains and exhibited bactericidal activity to homologous and heterologous NTHi strains.

Rat Response

• Vaccination Protocol: Four-day-old Sprague-Dawley rats were randomized into 10 groups with a mother for each group of 10 infants. The infants were immunized i.p. with 0.1 ml of the appropriate dilutions of mouse rNucA antiserum from week 10. Preimmune serum and PCM buffer were used as negative controls. The positive control group received a monoclonal antibody raised against Hib capsular polysaccharide (MAbE117.5). All dilutions of sera and cells were done in PCM buffer (Zagursky et al., 2000).
• Challenge Protocol: Approximately 24 h after immunization, the infant rats were challenged i.p. with approximately 50 CFU (0.1 ml) of virulent Hib Eagan. Approximately 20 to 24 h postchallenge, 10 µl of blood was taken from the tail and viable Hib CFU were determined from duplicate dilutions of blood (Zagursky et al., 2000).
• Efficacy: The group receiving a 1:2 dilution of mouse anti-rNucA pooled sera showed about a 10-fold reduction in the level of bacteremia compared to the group vaccinated with week 0 (preimmune) pooled mouse sera (Zagursky et al., 2000).