• Vaccine Name: PbVac P. Berghei Whole-Sporozoite Vaccine
• Target Pathogen: Plasmodium spp.
• Target Disease: Malaria
• Type: Inactivated or "killed" vaccine
• Status: Research
• Host Species for Licensed Use: Baboon
• Antigen: PbVac has been engineered to express the immunodominant Pf antigen, the circumsporozoite protein (PfCS), flanked by the Pb pre-erythrocytic stage-specific promoter, UIS4 (upregulated in infective sporozoites 4). PbVac infects and develops in human hepatocytes but not in human red blood cells. (Mendes et al., 2018)
• Immunization Route: Intramuscular injection (i.m.)
• Description: PbVac is a transgenic line of the rodent malaria parasite P. berghei (Pb) that expresses the P. falciparum (Pf) circumsporozoite protein (PfCS). It is capable of infecting and developing in human hepatocytes but not in human erythrocytes, and inducing neutralizing antibodies against the human Pf parasite.

Rabbit Response

• Host Strain: NZW rabbits
• Vaccination Protocol: This study performed an extensive evaluation of potential toxicity resulting from 5 consecutive administrations of PbVac delivered to rabbits by 97 infective mosquito bites each, ensuring 75 effective bites per administration. (Mendes et al., 2018)
• Immune Response: After vaccination, the parasite is completely eliminated from rabbits’ livers and all other organs analyzed up to 10 days after its administration. Pre-clinical results has shown that PbVac is unable to lead to a patent blood stage infection in rabbits and is incapable of developing in human erythrocytes. (Mendes et al., 2018)
• Description: This study revealed the absence of toxicity as a result of vaccine administration, indicating the safety of its use in non-permissive human hosts.