IN HEALTHY PRIMATES, CIRCULATING AUTOREACTIVE T-CELLS MEDIATE AUTOIMMUNE-DISEASE

A T cell response against myelin basic protein (MBP) is thought to con tribute to the central nervous system (CNS) inflammation that occurs i n the human demyelinating disease multiple sclerosis. To test whether MBP-reactive T cells that are normally retrieved from the circulation are capable of inducing CNS disease, MBP-reactive T cell clones were i solated from the peripheral blood of healthy, unimmunized Callithrix j acchus (C. jacchus) marmosets. This primate species is characterized b y a natural chimerism of bone marrow elements between siblings that sh ould make possible adoptive transfer of MBP-reactive T cells. We repor t that MBP-reactive T cell clones efficiently and reproducibly transfe r CNS inflammatory disease between members of C. jacchus chimeric sets . The demyelination that is characteristic of experimental allergic en cephalomyelitis induced in C. jacchus by immunization against human wh ite amtter did not occur after adoptive transfer of the MBP-reactive c lones. It was noteworthy that encephalitogenic T cell clones were dive rse in terms of their recognition of different epitopes of MBP, distin guishing the response in C. jacchus from that in some inbred rodents i n which restricted recognition of MBP occurs. These findings are the f irst direct evidence that natural populations of circulating T cells d irected against a CNS antigen can mediate an inflammatory autoimmune d isease.