Informing development decisions around malaria antigens

MVI is establishing multi-partner collaborations to better define the immune correlates of protection of RTS,S in both controlled human challenge and field studies. We are focusing on the evaluation and development of functional assays to assess the ability of antibodies to neutralize sporozoites and block invasion into liver cells.

Since Plasmodium falciparum does not infect laboratory animals, traditionally only in vitro assays have been used to assess immune responses in individuals exposed to or immunized against malaria. Transgenic rodent or non-human primate parasites expressing P. falciparum or P. vivax antigens can be used to elucidate information about the impact of vaccine-induced antibodies in vivo as they allow infection of laboratory animals immunized with murine or primate malaria parasites harboring P. falciparum antigens and detection of immune responses relevant to protection. We currently provide support for researchers at Johns Hopkins University to develop preclinical challenge models in rodents.

Malaria vaccine developers are fortunate to have access to a challenge model to evaluate the safety and protective efficacy of new approaches in human volunteers. This model was critical in accelerating the development of RTS,S, which is now in Phase 3 clinical testing. However, there are few places able to test the safety and efficacy of malaria vaccine candidates in humans. To ensure capacity for future clinical efficacy studies MVI has supported the Seattle Biomedical Research Institute (Seattle BioMed) Malaria Clinical Trial Center (MCTC), a facility devoted to testing the safety and efficacy of malaria vaccine candidates in humans. To learn more about this initiative, go to the MCTC fact sheet.