A method for treating multiple sclerosis in a subject in need of such treatment is provided. The method includes administering a) polysaccharide A and b) vitamin D or a vitamin D metabolite to the subject in an amount effective to treat multiple sclerosis. Also provided is a method for increasing TREG cells in a subject. The method includes administering a) polysaccharide A and b) vitamin D or a vitamin D metabolite to the subject in an amount effective to increase the number of TREG cells in the central nervous system of the subject.
