 Immunogenicity of the vaccine will be assessed by standardized assays for antibody levels against AMA1-3D7 and AMA1-FVO, and an in vitro growth inhibition assay GIA. The cellular basis of the immune responses will be evaluated by enumeration of relevant B and T cell subpopulations, including total and antigen-specific naive, memory and effector subpopulations specific for the antigens. The frequencies of B and T cells specific for the vaccine antigens in the group that received AMA1-C1 Alhydrogel R will be compared to those in the group receiving Alhydrogel R alone. The total and antigen-specific cell frequencies in pre-immune day 0 samples will serve as additional negative controls for the immunization. The goal of the study is to augment previously collected safety data for the 80 microgram antigen dose with a larger cohort, and to study the safety and immunogenicity of an accelerated vaccination schedule. 