AN EPITOPE ON THE SURFACE ENVELOPE GLYCOPROTEIN (GP130) OF SIMIAN IMMUNODEFICIENCY VIRUS (SIV(MAC)) INVOLVED IN VIRAL NEUTRALIZATION AND T-CELL ACTIVATION

SIVmac infection of macaques is an important animal model for HIV infe ction and AIDS; this model is being utilized for development of antivi ral therapies and vaccines. In the present article, we sought to ident ify neutralization epitopes of SIVmac envelope surface glycoprotein (g p130). Algorithms were used to predict antigenicity of specific region s. Four regions from the primary amino acid sequence of the viral surf ace glycoprotein were selected. A synthetic peptide representing one o f these regions (414-434) induced virus-neutralizing antibodies in mic e; in addition, this peptide induced T cell-proliferative responses in macaques. To address the in vivo relevance of these observations, we demonstrated that experimentally infected macaques produce antibodies to the neutralization epitope. In addition, rhesus macaques protected against infection by an inactivated SIV vaccine develop antibodies tha t bind to peptide 414-434. These observations demonstrate that the reg ion that includes the sequence 414-434 in the fourth variable domain ( V4) of SIVmac gp130 contains both a linear neutralization epitope and a T cell epitope.