Dengue virus protein recognition by virus-specific murine CD8+ cytotoxic T lymphocytes

The identification of the protein targets for dengue virus-specific T lymphocytes may be useful for planning the development of subunit vaccines against dengue. We studied the recognition by murine dengue virus-specific major histocompatibility complex class I-restricted, CD8+ cytotoxic T lymphocytes (CTL) of dengue virus proteins using recombinant vaccinia viruses containing segments of the dengue virus genome. CTL from H-2k mice recognized a single serotype-cross-reactive epitope on the nonstructural (NS) protein NS3. CTL from H-2b mice recognized a serotype-cross-reactive epitope that was localized to NS4a or NS4b. CTL from H-2d mice recognized at least three epitopes: a serotype-specific epitope on one of the structural proteins, a serotype-cross-reactive epitope on NS3, and a serotype-cross-reactive epitope on NS1 or NS2a. Our findings demonstrate the limited recognition of dengue virus proteins by CTL from three inbred mouse strains and the predominance of CTL epitopes on dengue virus nonstructural proteins, particularly NS3. Since human dengue virus-specific CTL show similar patterns of recognition, these findings suggest that nonstructural proteins should be considered in designing vaccines against dengue.