In this study, 90 volunteers will be progressively enrolled into one of six dose cohorts. Dose cohorts will be enrolled and vaccinated in a consecutive fashion. The 15 volunteers in each cohort will be subsequently randomized in a 1:2 ratio to receive either the Na-GST-1/Alhydrogel® (n=5) or Na-GST-1/Alhydrogel®/GLA-AF (n=10). In the first, third and fifth cohorts, volunteers will be randomized to receive either Na-GST-1/Alhydrogel® (n=5) OR Na-GST-1/Alhydrogel® co-administered with 1 µg GLA-AF (n=10), while in the second, fourth, and sixth cohorts, volunteers will be randomized to receive either Na-GST-1/Alhydrogel® (n=5) or Na-GST-1/Alhydrogel® co-administered with 5 µg GLA-AF (n=10).