Fig. 1.

Molecular approach to detect CD8+ T-cell epitope specificity directly ex vivo. Overlapping segments were amplified from the Theiler’s murine encephalomyelitis virus (TMEV) genome as noted in (A) and Table 1. In (B), overlapping TMEV genomic segments were cloned into pcDNA 3.1 His A. Individual wells of Cos-7 cells are co-transfected with either major histocompatibility (MHC) class I molecule K^b or D^b and a specific TMEV genomic segment. At 24–48 hours after transfection, Cos-7 cells express TMEV peptide presenting MHC class I molecules. Upon epitope recognition, central nervous system (CNS)–infiltrating and spleen-derived CD8+ T cells express detectible levels of interferon (IFN)–γ. This molecular approach is designed to enable recognition of all TMEV restricted CD8+ T-cell responses.