The simian immunodeficiency virus envelope glycoprotein contains two epitopes presented by the Mamu-A*01 class I molecule

Cytotoxic T lymphocyte (CTL) responses against the simian immunodeficiency virus (SIV) envelope and Gag proteins were monitored in a Mamu-A*01-positiv e rhesus macaque infected with SIVsmE660. Peripheral blood mononuclear cell s (PBMC) cultured with synthetic peptides spanning the entire gp160 and Gag coding region recognized a total of three epitopes. One located in Gag was identified as the previously described Mamu-A*01-restricted p11cC-->M epit ope (CTPYDINQM). The other two epitopes, designated p15m and p54m, were loc ated in the gp160 envelope protein. Both were nine amino acids in length an d were predicted to bind Mamu-A*01 because they contained proline and leuci ne residues at positions 3 and 9, respectively. Indeed, expression of this class I major histocompatibility complex molecule was required for target c ell recognition by envelope-specific CD8(+) T cells directed against both e pitopes. These Mamu-A*01-restricted epitopes in the SIV envelope will be us eful for monitoring immune responses in vaccinated or infected animals.