A Next-Generation Cleaved, Soluble HIV-1 Env Trimer, BG505 SOSIP.664 gp140, Expresses Multiple Epitopes for Broadly Neutralizing but Not Non-Neutralizing Antibodies

PLoS Pathog. 2013 Sep;9(9):e1003618. doi: 10.1371/journal.ppat.1003618. Epub 2013 Sep 19.

Abstract

A desirable but as yet unachieved property of a human immunodeficiency virus type 1 (HIV-1) vaccine candidate is the ability to induce broadly neutralizing antibodies (bNAbs). One approach to the problem is to create trimeric mimics of the native envelope glycoprotein (Env) spike that expose as many bNAb epitopes as possible, while occluding those for non-neutralizing antibodies (non-NAbs). Here, we describe the design and properties of soluble, cleaved SOSIP.664 gp140 trimers based on the subtype A transmitted/founder strain, BG505. These trimers are highly stable, more so even than the corresponding gp120 monomer, as judged by differential scanning calorimetry. They are also homogenous and closely resemble native virus spikes when visualized by negative stain electron microscopy (EM). We used several techniques, including ELISA and surface plasmon resonance (SPR), to determine the relationship between the ability of monoclonal antibodies (MAbs) to bind the soluble trimers and neutralize the corresponding virus. In general, the concordance was excellent, in that virtually all bNAbs against multiple neutralizing epitopes on HIV-1 Env were highly reactive with the BG505 SOSIP.664 gp140 trimers, including quaternary epitopes (CH01, PG9, PG16 and PGT145). Conversely, non-NAbs to the CD4-binding site, CD4-induced epitopes or gp41ECTO did not react with the trimers, even when their epitopes were present on simpler forms of Env (e.g. gp120 monomers or dissociated gp41 subunits). Three non-neutralizing MAbs to V3 epitopes did, however, react strongly with the trimers but only by ELISA, and not at all by SPR and to only a limited extent by EM. These new soluble trimers are useful for structural studies and are being assessed for their performance as immunogens.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • AIDS Vaccines / therapeutic use
  • Amino Acid Substitution
  • Antibodies, Monoclonal / metabolism*
  • Antibodies, Neutralizing / metabolism*
  • Antibody Affinity
  • Antibody Specificity
  • Epitopes*
  • HIV Antibodies / metabolism*
  • HIV Infections / immunology
  • HIV Infections / prevention & control
  • HIV-1 / immunology
  • Humans
  • Immunoglobulin Fab Fragments / metabolism*
  • Molecular Weight
  • Mutant Proteins / antagonists & inhibitors
  • Mutant Proteins / chemistry
  • Mutant Proteins / metabolism
  • Peptide Fragments / antagonists & inhibitors
  • Peptide Fragments / chemistry
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism
  • Protein Aggregates
  • Protein Stability
  • Recombinant Fusion Proteins / chemistry
  • Solubility
  • env Gene Products, Human Immunodeficiency Virus / antagonists & inhibitors*
  • env Gene Products, Human Immunodeficiency Virus / chemistry
  • env Gene Products, Human Immunodeficiency Virus / genetics
  • env Gene Products, Human Immunodeficiency Virus / metabolism

Substances

  • AIDS Vaccines
  • Antibodies, Monoclonal
  • Antibodies, Neutralizing
  • Epitopes
  • HIV Antibodies
  • Immunoglobulin Fab Fragments
  • Mutant Proteins
  • Peptide Fragments
  • Protein Aggregates
  • Recombinant Fusion Proteins
  • env Gene Products, Human Immunodeficiency Virus
  • gp140 envelope protein, Human immunodeficiency virus 1