Clinical Trial of the PfSPZ Vaccine

Inclusion Criteria: 1. Healthy adults (male or non-pregnant female) 18-50 years of age, inclusive. 2. Able and willing to participate for the duration of the study. 3. Able and willing to provide written (not proxy) informed consent. 4. Women of childbearing potential must agree to use effective means of birth control through the duration of the study. 5. Willing to refrain from blood donation (except as required in this study) for 3 years following P. falciparum challenge. 6. Agree not to travel to a malaria endemic region during the entire course of the trial. Exclusion Criteria: 1. Any history of malaria infection, or travel to a malaria endemic region within 6 months prior to first immunization. 2. History of long term residence (\>5 years) in area known to have significant transmission of P. falciparum. 3. Positive HIV, HBsAg or HCV serology. Positive sickle cell screening test. 4. Has evidence of increased cardiovascular disease risk (defined as \> 10%, 5 year risk) as determined by the method of Gaziano (Gaziano 2008). Risk factors include sex, age (years), systolic blood pressure (mm Hg), smoking status, body mass index (BMI, kg/mm2), reported diabetes status, and blood pressure. 5. Current use of systemic immunosuppressant pharmacotherapy. 6. An abnormal EKG, defined as one showing pathologic Q waves and significant ST-T wave changes; left ventricular hypertrophy; any non-sinus rhythm excluding isolated premature atrial contractions; right or left bundle branch block; or advanced (secondary or tertiary) A-V heart block. 7. Current significant medical condition (cardiovascular, hepatic, renal, or hematological) or evidence of any other serious underlying medical condition identified by medical history, physical examination, or laboratory examination. 8. History of a splenectomy. 9. History of any other illness or condition which, in the investigator's judgment, may substantially increase the risk associated with the volunteer's participation in the protocol or compromise the scientific objectives. This may include psychiatric disorders (such as personality disorders, anxiety disorders, or schizophrenia) or behavioral tendencies (including active alcohol or drug abuse) discovered during the screening process that in the opinion of the investigator would make compliance with the protocol difficult. 10. Plan for surgery between enrollment and challenge. 11. Females who are pregnant or nursing, females who plan on becoming pregnant or plan to nurse during the study period. 12. Known allergy to any component of the vaccine formulation, history of anaphylactic response to mosquito bites, retinal or visual field changes, or known allergy to the anti-malarial chloroquine phosphate, which will be used to treat volunteers developing malaria after P. falciparum challenge. 13. Participation in any study involving another investigational vaccine or drug within 90 days prior to the screening visit, or plan to participate in another investigational vaccine/drug research during or within 1 month following participation in this study. 14. Personal beliefs that prohibit the receiving of vaccine product containing human serum albumin within the diluent. 15. Use or planned use of any drug with anti-malarial activity that would coincide with immunization or challenge. 16. History of psoriasis or porphyria, which may be exacerbated after treatment with chloroquine. 17. Anticipated use of medications known to cause drug reactions with chloroquine or atovaquone- proguanil (Malarone) such as cimetidine, metoclopramide, antacids, and kaolin.