In this first in human study the aim is to assess the safety, pharmacokinetics and pharmacodynamics of 2B3-201 in a randomized, first in human, double-blind, placebo- and active comparator- controlled 3-way crossover study in 18 healthy male subjects (part 1). Furthermore, the findings obtained from part 1 will be extended and confirmed in a subsequent parallel open label study in 18 healthy male and 12 MS patients and an open label study with methylprednisolone as comparator in 12 female volunteers (part 2).