Human cellular immune response to copolymer I and myelin basic protein.

Copolymer I (Cop I) is being tested as a treatment for MS because it protects animals against experimental allergic encephalomyelitis, and because there is immunologic cross-reactivity reported between Cop I and myelin basic protein (MBP). From the peripheral blood mononuclear cells of four normal individuals, we isolated helper-phenotype T-cell lines that reacted in vitro with Cop I or MBP. Cop I-reactive cell lines did not respond to MBP, nor did MBP-reactive T-cell lines respond to Cop I. Antigen-specific immune tolerance was induced in MBP-reactive cell lines by exposure to MBP in vitro, but similar exposure to Cop I did not induce tolerance in the MBP-reactive cell lines. We found no evidence of immunologic cross-reactivity between Cop I and MBP.