Characterization of a stable HIV-1 B/C recombinant, soluble, and trimeric envelope glycoprotein (Env) highly resistant to CD4-induced conformational changes

J Biol Chem. 2017 Sep 22;292(38):15849-15858. doi: 10.1074/jbc.M117.803056. Epub 2017 Jul 25.


The HIV-1 envelope (Env) is a glycoprotein consisting of a trimer of heterodimers containing gp120 and gp41 subunits that mediates virus entry and is a major target of broadly neutralizing antibodies (bnAbs) developed during infection in some individuals. The engagement of the HIV-1 gp120 glycoprotein to the host CD4 protein triggers conformational changes in gp120 that allow its binding to co-receptors and is necessary for virus entry to establish infection. Native-like HIV-1 Env immunogens representing distinct clades have been proposed to improve immunogenicity. In the present study, we examined the basis of resistance of an HIV-1 B/C recombinant Env (LT5.J4b12C) to non-neutralizing antibodies targeting CD4-induced Env epitopes in the presence of soluble CD4 (sCD4). Using native polyacrylamide gel shift assay and negative-stain EM, we found that the prefusion conformational state of LT5.J4b12C trimeric Env was largely unaffected in the presence of excess sCD4 with most Env trimers appearing to be in a ligand-free state. This resistance to CD4-induced conformational changes was associated with a lower affinity for CD4. Moreover, the LT5.J4b12C trimeric Env preferentially bound to the neutralizing antibodies compared with non-neutralizing antibodies. Taken together, we report on an HIV-1 B/C recombinant, native-like trimeric Env protein that is highly resistant to CD4-induced conformational changes but displays epitopes recognized by a diverse array of bnAbs. Such features make this B/C recombinant trimeric Env a useful addition to the pool of other recently identified native-like HIV-1 Env trimers suitable for use as antigenic bait for bnAb isolation, structural studies, and use as potential immunogens.

Keywords: B/C recombinant; SOSIP.664; broadly neutralizing antibodies; cluster of differentiation 4 (CD4); envelope; human immunodeficiency virus (HIV); trimeric protein; viral protein; viral replication; virus entry.

MeSH terms

  • Amino Acid Sequence
  • Antibodies, Monoclonal / immunology
  • Antibodies, Neutralizing / immunology
  • Broadly Neutralizing Antibodies
  • CD4 Antigens / chemistry*
  • CD4 Antigens / metabolism
  • CD4 Antigens / pharmacology*
  • Epitopes / immunology
  • HEK293 Cells
  • HIV Antibodies
  • HIV-1*
  • Humans
  • Models, Molecular
  • Protein Conformation
  • Protein Multimerization*
  • Protein Stability / drug effects
  • Protein Structure, Quaternary
  • Recombinant Proteins / chemistry*
  • Recombinant Proteins / immunology
  • Recombinant Proteins / metabolism
  • Solubility
  • env Gene Products, Human Immunodeficiency Virus / chemistry*
  • env Gene Products, Human Immunodeficiency Virus / immunology
  • env Gene Products, Human Immunodeficiency Virus / metabolism


  • Antibodies, Monoclonal
  • Antibodies, Neutralizing
  • Broadly Neutralizing Antibodies
  • CD4 Antigens
  • Epitopes
  • HIV Antibodies
  • Recombinant Proteins
  • VRC01 monoclonal antibody
  • env Gene Products, Human Immunodeficiency Virus

Associated data

  • PDB/4RQS
  • PDB/5THR
  • PDB/4QRS