• Type: Subunit vaccine
• Status: Research
• Host Species for Licensed Use: Macaque
• Antigen: PvRII, receptor-binding domain of Plasmodium vivax Duffy binding protein, region II, with a C-terminal 6-histidine tag expressed in E. coli. (Moreno et al., 2008)
• PvDBPII gene engineering:
  • Type: Recombinant protein preparation
  • Description: The designed gene encoding PvRII was synthesized using overlapping oligomers (Midland Certified Reagent Company) and cloned in plasmid pET28a(+) (Novagen) at NcoI and SalI sites. Expression of recombinant PvRII using synthetic gene was higher compared with native gene. (Yazdani et al., 2006)
  • Detailed Gene Information: Click Here.
• Preparation: PvRII from P. vivax Salvador I strain was cloned as a NcoI-SalI fragment in the E. coli expression vector pET28a(+). Protein expression of the recombinant 6-His tag PvRII was induced with 1 mM IPTG for 4 hours and purified. 50 μg and 10 μg of PvRII were adsorbed to Alhydrogel. (Moreno et al., 2008)
• Immunization Route: Intramuscular injection (i.m.)
• Description: The PvRII/ Alhydrogel vaccine uses recombinant PvRII (region II), the receptor-binding domain of the Plasmodium vivax Duffy binding protein. Antibodies raised against the P.vivax Duffy binding protein, which belong to a family of erythrocyte binding protiens residing in region II, block erythrocyte invasion in the malaria infection process. Recombinant PvRII formulated with Alhydrogel yielded antibodies with significant binding inhibitory activity.. (Moreno et al., 2008)

Macaque Response

• Host Strain: Healthy rhesus macaques of Chinese origin from the Yerkes National Primate Research Center facility
• Vaccination Protocol: Selected animals were matched by age, sex and weight, housed in social settings and randomly assigned to six experimental groups of 5 individuals each that received different vaccine formulations (Groups 1-6) and three control groups of two individuals each that received adjuvant alone (Groups 7-9). Groups 1 and 2 were immunized with 50 μg and 10 μg of PvRII adsorbed to Alhydrogel, respectively. Intramuscularly, priming into the right quadriceps femoris on day 0, first boost into the right musculus deltoideus on day 60 and the last boost into the left musculus deltoideus on day 150. (Moreno et al., 2008)
• Immune Response: Antibody titers, determined by ELISA, increased in PvRII formulated with Alhydrogel, refolded PvRII induced functional antibodies with the potential to inhibit parasite invasion. (Moreno et al., 2008)