Evidence for similar recognition of the conserved neutralization epitopes of human immunodeficiency virus type 1 envelope gp120 in humans and macaques

We compared the immune responses to the human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins in humans and macaques with the use of clad e A and clade B isogenic V3 loop glycan-possessing and -deficient viruses. We found that the presence or absence of the V3 loop glycan affects to simi lar extents immune recognition by a panel of anti-HIV human and anti-simian /human immunodeficiency virus (anti-SHIV) macaque sera. All sera tested neu tralized the glycan-deficient viruses, in which the conserved CD4BS and CD4 i epitopes are more exposed, better than the glycan-containing viruses. The titer of broadly neutralizing antibodies appears to be higher in the sera of macaques infected with glycan-deficient viruses. Collectively, our data add legitimacy to the use of SHIV-macaque models for testing the efficacy o f HIV-1 Env-based immunogens. Furthermore, they suggest drat antibodies to the CD4BS and CD4i sites of gp120 are prevalent in human and macaque sera a nd that the use of immunogens in which these conserved neutralizing epitope s are more exposed is likely to increase their immunogenicity.