IMMUNITY TO TCR PEPTIDES IN MULTIPLE-SCLEROSIS .2. T-CELL RECOGNITIONOF V-BETA-5.2 AND V-BETA-6.1 CDR2 PEPTIDES

The biased expression of V beta 5.2 and V beta 6.1 by T cells specific for myelin basic protein (BP) has led to our use of TCR peptides from these V gene sequences to induce anti-TCR immunity in patients with m ultiple sclerosis (MS). Injection of V beta 5.2-39-59 or V beta 6.1-39 -59 peptides significantly increased the peptide specific T cell frequ ency in 7 of 11 MS patients, often with an accompanying delayed hypers ensitivity reaction at the injection site. Here, we validate these cel lular immune responses by characterizing TCR peptide specific T cells from an MS patient with biased V beta 5.2 expression in BP reactive T cells before treatment with TCR peptides, and from two MS patients in whom the frequencies of anti-TCR peptide specific T cells were signifi cantly boosted after injection with low doses of TCR peptides. In both cases, T cell lines were established with relative ease, especially a fter boosting with the peptides. A V beta 5.2-39-59 reactive line resp onded selectively to the boosting peptide and was restricted by both M HC class I (HLA-B7) and MHC class II (HLA-DR2) molecules. Characteriza tion of 22 clonal isolates revealed that the responding T cells were p redominantly activated CD4(+)CD8(lo), circulating memory cells restric ted by either HLA-B7 or HLA-DR2, that utilized mainly V beta 4, V beta 6, V beta 12, and V beta 14, but not V beta 5.2 in their TCR. T cell isolates specific for V beta 6.1-39-59 possessed similar characteristi cs but contained specificities cross-reactive with an N-terminal seque nce on V beta 5.2-39-59. Upon stimulation with peptide or Con A, the T CR peptide specific T cell lines had increased message production for IFN-gamma, GM-CSF, IL-4, IL-5, and to a lesser degree, IL-2. This lymp hokine mRNA profile differed from a BP-specific T cell line that produ ced message for IFN-gamma and GM-CSF but low or absent levels of IL-4 and IL-5. The extensive parallels between human T cells specific for V beta 5.2 and V beta 6.1 CDR2 peptides and rat T cells specific for V beta 8.2 CDR2 peptide that are highly protective against experimental encephalomyelitis strengthen the rationale for the therapeutic use of TCR peptides in human autoimmunity.