A Study to Assess Safety, Immunogenicity and Parasite Growth Inhibition of an Asexual Blood Stage Vaccine for P. Falciparum Malaria

Inclusion Criteria: * Subject is willing and able to give informed consent for participation in the study * Healthy, non pregnant adult aged 18 - 50 years * Resident in or near Oxford for the duration of the challenge study * Seropositive for CMV and EBV * Female subjects of child bearing potential must be willing to ensure that they practice effective contraception during the study * Males must be willing to use barrier contraception from day of first vaccination onwards until 3 months after the second vaccination * Able (in the Investigator's opinion) and willing to comply with all study requirements * Willing to allow his or her General Practitioner and consultant, if appropriate, to be notified of participation in the study * Agreement to permanently refrain from blood donation. Exclusion Criteria: * Any deviation from the normal range in biochemistry or haematology blood tests or in urine analysis as defined in Appendix B * Female patient/subject who is pregnant, lactating or planning pregnancy during the course of the study * Healthy volunteers who have participated in another research study involving an investigational product in the past 12 weeks * Subjects who have previously received an investigational malaria vaccine * 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 * Travel to a malaria endemic area within the previous 6 months * Planned travel to malarious areas during the study period * Any history of malaria * Contraindication to both anti-malarial drugs (Riamet® and chloroquine) * concomitant use of other drugs known to cause QT-interval prolongation, ( e.g. macrolides, quinolones, amiodarone etc) * An estimated ten year risk of fatal cardiovascular disease of ≥5%, as estimated by the Systematic Coronary Risk Evaluation (SCORE) system (Conroy 2003) * Family history of sudden cardiac death * History of cardiac arrhythmia or prolonged QT syndrome * Any history of severe allergic reaction or anaphylaxis * History of a known allergy to nickel * Any confirmed or suspected immunosuppressive or immunodeficient state, including HIV infection; asplenia; recurrent severe infections and chronic (more than 14 days) immunosuppressant medication within the past 6 months * History or evidence of pre-existing autoimmune or antibody mediated disease or laboratory evidence of possible autoimmune disease (defined as anti-dsDNA ≥ 25 IU/mL) * Seropositive for hepatitis B surface antigen (HBsAg) or antibodies to hepatitis C virus * Any on-going chronic illness requiring hospital specialist supervision * Administration of immunoglobulins and/or any blood products within the three months preceding the planned administration of the vaccine candidate * History of or current intravenous drug abuse * Suspected or known current alcohol abuse as defined by an alcohol intake of greater than 42 units every week * Any other significant disease or disorder which, in the opinion of the Investigator, may either put the subject at risk because of participation in the study, or may influence the result of the study, or the subject's ability to participate in the study. * Investigator assessment of lack of willingness to participate and comply with all requirements of the protocol