Distribution of CNS-specific CD4⁺ and CD8⁺ T-cell responses. CFSE-based proliferation assays were performed on PBMC specimens from 8 healthy individuals and 43 untreated patients with MS (RRMS, n = 17; PPMS, n = 20; SPMS, n = 6). Each subject was tested against 15 distinct pools of CNS peptides, representing 9 distinct CNS target proteins. The y-axis demonstrates the mean number of peptide pools (+ 2 SEM) against which a positive response was observed in the indicated subject groups. Black bars (▪) indicate CD4⁺ T-cell responses, whereas gray bars () represent CD8⁺ responses. The ranges are indicated in parentheses. ^*CD4⁺ responses to a significantly higher array of peptide pools were observed compared with CD8⁺ responses (P < .05).