We will do this by giving 48 participants three sets of vaccinations over 8 weeks, then exposing them to malaria infection by allowing mosquitoes infected with malaria to bite under carefully regulated conditions. We will follow participants closely to observe if and when they develop malaria. If the vaccine combination provides some protection against malaria, participants will take longer to develop malaria than usual or will not develop malaria at all. We will also recruit 4 individuals to be control subjects - these participants won't receive any vaccinations but will be challenged with malaria.