Sporozoite Challenge of Polyprotein Vaccinees

Inclusion Criteria: * Healthy non-pregnant adults aged 18 to 50 years * The vaccinated group will be subjects who have received the vaccine regime described for group 6 or 7 in VAC027.1 * Resident in or near Oxford, UK for the duration of the challenge study * For females only, willingness to practice effective contraception during the challenge study. * Agreement to refrain from blood donation during the course of the study * Written informed consent * Willingness to allow the investigators to access hospital and General Practitioner medical notes * Willingness to undergo an HIV test Exclusion Criteria: * Any deviation from the protocol-defined normal range in biochemistry or haematology blood tests or in urine analysis * Prior receipt of an investigational malaria vaccine (unless administered in VAC027.1) * Use of any investigational or non-registered drug, live vaccine or medical device other than the study vaccine within 30 days preceding dosing of study vaccine, or planned use during the study period * Administration of chronic immunosuppressive drugs or other immune modifying drugs within six months of vaccination * History of malaria chemoprophylaxis with chloroquine within 5 months prior to the planned challenge, with Lariam within 6 weeks prior to the challenge, and Riamet within 2 weeks prior to the challenge * Any history of malaria * Travel to a malaria endemic country within the previous 3 months prior to the planned challenge * Planned travel to malarious areas during the study period * Any confirmed or suspected immunosuppressive or immunodeficient condition, including human immunodeficiency virus (HIV) infection and asplenia * Evidence of cardiovascular disease * History of cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ) * History of haemoglobinopathies * History of diabetes mellitus * Chronic or active neurological disease requiring ongoing specialist supervision * Chronic gastrointestinal disease requiring ongoing specialist supervision * History of \> 2 hospitalisations for invasive bacterial infections (pneumonia, meningitis) * Suspected or known current alcohol abuse as defined by an alcohol intake of greater than 42 units every week * Seropositive for hepatitis B surface antigen (HBsAg) * Seropositive for hepatitis C virus (antibodies to HCV) * Hepatomegaly, right upper quadrant abdominal pain or tenderness * Evidence of serious psychiatric condition * Any other on-going chronic illness requiring hospital specialist supervision * Acute disease at the time of enrolment * Administration of immunoglobulins and/or any blood products within the three months preceding the planned administration of the vaccine candidate * Pregnant or lactating female * Female who is willing or intends to become pregnant during the study * History of severe reactions or allergy to mosquito bites * PI assessment of lack of willingness to participate and comply with all requirements of the protocol * History or clinical evidence of intravenous drug abuse * Any other finding which in the opinion of the investigator would significantly increase the risk of having an adverse outcome from participating in this protocol