A method of inducing specific immune tolerance to myelin in an individual is provided. The method includes introducing directly into a lymph node of the individual an effective amount of a composition that contains a myelin antigen, a biodegradable material and at least one tolerogenic agent. The method is suitable for reducing the severity of symptoms of multiple sclerosis in individuals who suffer from primary-progressive multiple sclerosis (PPMS), and can halt or even reverse PPMS progression.