Immunogenicity testing will include IgG antibody responses to Na-GST-1, by a qualified indirect enzyme-linked immunosorbent assay (ELISA), on serum obtained prior to each study vaccination and CHHI, and at time points after each vaccination and after CHHI (see Appendix A); the affinity of vaccine-induced antibodies against Na-GST-1 using Surface Plasmon Resonance; the functional activity of vaccine-induced antibodies via in vitro enzyme neutralization assay; antigen-specific memory B cell responses; and, the innate immune responses to each of the TLR receptor immunostimulants.