An interval no less than 60 days following the first dose will separate the first dose of each volunteer group receiving different rFla-MBP doses. All volunteers will receive three immunizations. The first dosing time point is Day 0, the second is Day 14 (+/- 1 day), the third is day 28 (+/- 2 days). Blood and stool specimens will be collected at intervals to examine systemic and mucosal vaccine antigen-specific immune responses. Vaccine safety will be actively monitored during vaccination and for 28 days following the third vaccine dose.