Structure and Immunogenicity of a Peptide Vaccine, Including the Complete HIV-1 gp41 2F5 Epitope

Abstract

Background: HIV-1 vaccines should elicit broadly neutralizing antibodies as the gp41 "membrane-proximal external region" targeting MAb2F5. Results: NMR disclosed unprecedented 2F5 peptide-epitope structures. Although overall conformation was preserved in different adjuvants, recovered antibodies after vaccination were functionally different. Conclusion: Membrane-inserted helical oligomers may encompass effective 2F5 peptide vaccines. Significance: Disclosing the structures that generate 2F5-like antibodies may guide future vaccine development.

The Atomic Structure of the HIV-1 gp41 Transmembrane Domain and Its Connection to the Immunogenic Membrane-proximal External Region

“…At the N terminus, the hinge segment 671 NWFD 674 (33) is partially extended, consistent with the conformational flexibility put forward by previous NMR studies (24,26,29,33,34). This element is followed by a continuous ␣-helix extending to Gly-690.…”

“…Structure Calculation-Structures for peptide CpreTM in DPC micelles and in 25% HFIP and for TMDp in 25% HFIP were calculated from distance and dihedral angle constraints derived from NMR parameters by following the three-step protocol previously described for MPERp (34). Distance constraints were obtained from the cross-peaks present in 150-ms two-dimensional 1 H-1 H NOESY spectra, which were integrated using the standard SPARKY integration subroutine (SPARKY3), and the dihedral angle restraints for and angles were derived from 1 H ␣ and 13 C ␣ chemical shifts using the program TALOS (40).…”

“…For the cell infection inhibition assays (34,37), HIV-1 pseudoviruses were produced by transfection of human kidney HEK293T cells with the full-length env clone JRCSF (kindly provided by Jamie K. Scott and Naveed Gulzar, Simon Fraser University, British Columbia, Canada) using calcium phosphate. Cells were co-transfected with vectors pWXLP-GFP and pCMV8.91, encoding a green fluorescent protein and an envdeficient HIV-1 genome, respectively (provided by Patricia Villace, CSIC, Madrid, Spain).…”

Identification of a Continuous Neutralizing Epitope within UL128 of Human Cytomegalovirus

“…Whereas all of the 13B5 peptides stimulated robust binding antibodies, only 1 out of 5 mice in each of the vaccine groups immunized with K14CS or K16CS developed long-lasting NAb, and these responses were only modest compared to those observed previously by immunization with the PC. While the reasons for this discrepancy in 13B5 NAb potency and 13B5 peptide immunogenicity for stimulating NAb remain speculative, it is possible that the 13B5 epitope sequence in its native state within the PC forms a helical, bended, or "kinked" three-dimensional structure that is required for NAb induction (43). Consequently, without structural constraint by PC subunits, the 13B5 epitope structure is only inefficiently or rarely formed.…”

Chemically Modified Peptides Based on the Membrane-Proximal External Region of the HIV-1 Envelope Induce High-Titer, Epitope-Specific Nonneutralizing Antibodies in Rabbits

“…Anti-N-MPER titers are more varied within each group. The MPER peptide presentation and orientation in liposomes have been shown to be critical for immunogenicity, especially with tryptophan-680, which is adjacent to this tyrosine (39)(40)(41), suggesting that chemical modifications at this residue may change the orientation of the peptide in the bilayer.…”