A major goal in HIV-1 vaccine research is to develop an immunogen that can elicit
broadly neutralizing anti
bodies that efficiently neutralize a wide range of the HIV-1 su
btypes. Using
biopanning procedure we have selected linear peptide VGAFGSFYRLSVLQS mimicking the structure of discontinuous
binding sites of
broadly neutralizing anti
bodies 2G12 from phage peptide li
brary. As a protein carrier, we used the earlier designed artificial polyepitope immunogen named TBI (T- and B-cell immunogen), which comprises B-cell and T-helper epitopes from the HIV-1 Env and Gag proteins. On the
base of selected peptide mimotope VGAFGSFYRLSVLQS the artificial protein TBI-2g12 was constructed and its immunogenic properties was investigated. It was shown that the TBI-2g12 as well as the original TBI induces anti
bodies that recognize HIV-1 proteins and TBI protein using ELISA and immuno
blotting. However only anti-TBI-2g12 serum recognized the synthetic peptide mimotope VGAFGSFYRLSVLQS, whereas the anti
bodies against original TBI don鈥檛 recognize it.
The neutralization assay demonstrated that serum antibodies of the mice immunized with TBI-2g12 possess virus neutralizing activity. The addition of selected peptide leads to inhibition neutralizing activity of anti- TBI-2g12 serum. We conclude from these results that immunogen TBI-2g12 containing the selected peptide VGAFGSFYRLSVLQS elicits HIV-1 neutralizing antibodies during immunization. Our data suggest that this immunogen may be useful in designing effective HIV-vaccine candidates.