Necessity of continuous antigenic stimulation by the locally retained antigens in chronic relapsing experimental allergic encephalomyelitis.

Chronic relapsing experimental allergic encephalomyelitis has been induced in juvenile strain 13 guinea pigs with isologous spinal cord in Freund's complete adjuvant. Retention of antigen at the injection site and in the draining lymph nodes was studied by immunocytochemical staining with antiserum to myelin basic protein (BP). Antigen was detected in the skin more than 370 days after immunization, whereas it could be detected in the nodes only 200 days postinjection. Amputation of the hind feet to remove the antigenic depots prevented subsequent episodes of clinical EAE. Therefore, continuous antigenic stimulation by the antigen at the local skin site is more important in the induction of relapses than antigen in the draining lymph nodes.