Characterization of the response to myelin basic protein in a non human primate model for multiple sclerosis

The common marmoset Callithrix jacchus (C. jacchus) is an outbred species c haracterized by a naturally occurring bone marrow chimerism and susceptibil ity to a form of experimental autoimmune encephalomyelitis (EAE) resembling multiple sclerosis (MS). T cell clones specific for the myelin antigen, my elin basic protein (MBP), can be derived from both naive and immunized marm osets and can adoptively transfer EAE to compatible chimeric siblings. Here , we demonstrate that severel different antigenic determinants of MBP are r ecognized by these encephalitogenic T cell clones. Furthermore, PCR-based a nalysis of TCR V beta families does not show the preferential usage of any gene segment. Characterization of third complementarity determining regions (CDR3) fails to demonstrate a recurring motif characteristic of the T cell immune response to MBP in this species. Nevertheless, brief amino acid mot ifs are shared among marmoset clones and CDR3 sequences from MS samples. Th ese data suggest that, due to its outbred condition, the C. jacchus marmose t mounts a diverse pathogenic response to MBP. However, the findings that c ertain CDR3 sequences are identically expressed in different animals, or by different T cell clones, suggest that MBP-specific T cell populations may be clonally expanded following chronic antigenic stimulation in vivo.