Chronic experimental allergic encephalomyelitis in strain 2 guinea pigs. Absence of resistance to nervous system changes and sex dependence of clinical disease.

Experimental autoimmune (allergic) encephalomyelitis (EAE) was induced in Strain 2 guinea pigs, a strain usually regarded as resistant to EAE. The development of disease in groups of juvenile male or female Strain 2/N guinea pigs was irregular with clinical EAE manifesting only in some groups of females. All animals examined morphologically (12 females and 9 males), between 3 and 18 months postinoculation, showed extensive changes in the central nervous system, although 12 of these had displayed no neurologic signs. This silent central nervous system disease, reminiscent of similar phenomena in man, indicates that Strain 2/N is fully competent immunologically at the level of the target organ.