Site-directed serology using synthetic oligopeptides representing the C-terminus of the external glycoproteins of HIV-1, HIV-2, or SIVmac may distinguish subtypes among primate lentiviruses.

In this study the presence of a highly immunogenic domain located at the C-terminus of the external glycoproteins (EGP) of human and simian immunodeficiency viruses (HIV-1, HIV-2, and SIVMAC.) is shown using synthetic oligopeptides as antigens in enzyme immunoassays. This epitope is probably located within the last 13 and 15 residues of the EGP of HIV-1 and HIV-2, respectively. The C terminal epitope of the EGP of SIVMAC may involve residues located more upstream. Among the HIV-2/SIV serotype, we observed that the reactivity to the C-terminal epitope of gp120 was dependent of both species and geographical origin of the samples tested. It seems that this gp 120 C-terminal epitope could distinguish subtypes among the HIV-2/SIV serotype. Further studies, using site-directed enzyme immunoassays with synthetic peptides representing the C-terminus of the EGP derived from a wide variety of HIV2/SIV strains must be performed to confirm this observation. These kinds of assays may constitute important tools for use...