To identify a panel of multiple sclerosis patients (MS) for a phase I clinical trial of a T-cell receptor (TCR) peptide vaccine we characterized the T-cell populations present in the cerebrospinal fluids (CSF) of a large group of patients with respect to surface phenotype and state of activation, TCR beta chain utilization, features of the CDR3 junctional region, the extent of clonality and persistence of selected clonotypes over time. These CSF cell populations consist of approximately 60% CD4+ T-cells, half of which bear IL-2 receptors, indicating these activated T-cells may be part of the pathogenic process in MS. When these activated CD4+ T-cells were selectively expanded in IL-2/IL-4 supplemented cultures, an over-representation of several TCRV beta families was noted in 39/47 patients, the most frequent being V beta 6.5, V beta 6.7, V beta 2, V beta 5 and V beta 4. Biased expression of various members of the V beta 6 family was seen in 21 of this group of 39 patients. Clonal analysis of TCR beta 6 CDR3 sequences, revealed two notable features: clonal dominance and clonal persistence. CSF cells from two-thirds of MS patients contained a dominant clone comprising 50% or more of sequences and the same patient-specific clone could be shown to persist for up to 18 months. This clonal prevalence and over representation of V beta 6+TCR raises the possibility that immunization with a V beta 6 peptide vaccine may produce a regulatory immune response leading to a clinical benefit.

We report here the results of a phase I trial of a T-cell receptor (TCR) Vβ6 CDR2 region peptide vaccine in 10 patients with multiple sclerosis who showed biased over-representations of Vβ6 mRNA among T-cells in their cerebrospinal fluids (CSF). One group of 5 patients was immunized twice during a four week period with 100 μg of the TCRVβ6 peptide 39-LGQGPEF LTYFQNEAQLEKS-58 emulsified in incomplete Freund's adjuvant (IFA); the second group of 5 MS patients received 300 μg of the same peptide in IFA over a similar time period. Patients were monitored for adverse events, immunogenicity of the peptide and changes in their CSF T-cell populations. The results indicate that this peptide was immunogenic (T-cell proliferation assays and recall DTH responses) in some of the patients, although none of the immunized patients produced detectable anti-peptide antibodies. More importantly, we show that the 5 patients treated with higher doses of the vaccine displayed a slight decrease in CSF cellularity, a lack of growth of CSF cells in cytokine supplemented expansion cultures that implies a significant absence of a subset of activated CD4 T-cells and a marked diminution in Vβ6 mRNA levels among T-cells in these cultures. By comparison, in 5 patients receiving the lower dosage of the vaccine, CSF cellularity was the same or slightly increased over pre-vaccination levels, CSF cells from 1 patient failed to grow in expansion cultures and cultured CSF cells from 2 patients underwent a change from an oligoclonal Vβ6 pattern to one that was more polyclonal. These results justify a more thorough exploration of the use of TCR peptide vaccines as a possible therapeutic treatment for MS.