Phase I/II Trial of a Malaria Vaccine in Adults Living in the United States of America

Inclusion Criteria: * A male or non-pregnant female 18 to 50 years of age (inclusive) at the time of screening. * Written informed consent obtained from the subject before screening procedures. * Free of obvious health problems as established by medical history and clinical examination before entering into the study.\* * Available to participate for duration of study (approximately 15 months). * If the subject is female, she must be currently using birth control, must be surgically sterilized, or must be at least 1-year post menopausal. * Pass a comprehension assessment test. Exclusion Criteria: * Prior receipt of an investigational malaria vaccine. * Use of any investigational or non-registered drug or vaccine other than the study vaccine(s) within 28 days preceding the first dose of study vaccine, or planned use during the study period. * Administration of chronic immunosuppressants or other immune modifying drugs within six months of vaccination. * Chronic use of antibiotics with anti-malarial effects. * Planned administration/ administration of a vaccine not foreseen by the study protocol within 30 days of the first dose of vaccine(s). * History of use of anti-malarial medication within 60 days prior to vaccination. * Any history of malaria. * Known exposure to malaria within the previous 12 months. * Planned travel to malarious areas during the study period. * Any confirmed or suspected immunosuppressive or immunodeficient condition, including HIV infection. * A family history of congenital or hereditary immunodeficiency. * History of allergic disease or reactions likely to be exacerbated by any component of the vaccine. * Chronic or active neurologic disease including seizures, but not including a single febrile seizure as a child. * History of splenectomy. * Acute disease at the time of enrollment. * Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests. * Personal history of autoimmune disease or subjects who describe a first-degree relative with clearly documented autoimmune disease. * Seropositive for hepatitis B surface antigen. * Seropositive for Hepatitis C virus (antibodies to HCV). * Administration of immunoglobulins and/or any blood products within the three months preceding the first dose of study vaccine or planned administration during the study period. * Pregnant or lactating female. * Suspected or known current alcohol abuse as defined by the American Psychiatric Association in DSM IV. * Chronic or active intravenous drug use. * History of severe reactions to mosquito bites as defined as anaphylaxis. * Female who intends to become pregnant during the study. * Any history of anaphylaxis in reaction to vaccination. * A clinical history of sickle cell disease or sickle cell trait. * Any other significant finding that in the opinion of the investigator would increase the risk of having an adverse outcome from participating in this study.