Stabilized HIV-1 envelope glycoprotein trimers lacking the V1V2 domain, obtained by virus evolution.

TitleStabilized HIV-1 envelope glycoprotein trimers lacking the V1V2 domain, obtained by virus evolution.
Publication TypeJournal Article
Year of Publication2010
AuthorsBontjer I, Melchers M, Eggink D, David K, Moore JP, Berkhout B, Sanders RW
JournalJ Biol Chem
Date Published2010 Nov 19
KeywordsAmino Acid Sequence, Blotting, Western, Directed Molecular Evolution, env Gene Products, Human Immunodeficiency Virus, HIV Antibodies, HIV Antigens, HIV Infections, HIV-1, Humans, Immunoprecipitation, Models, Molecular, Molecular Sequence Data, Mutation, Neutralization Tests, Polysaccharides, Protein Structure, Tertiary, Sequence Homology, Amino Acid, Virus Replication

The envelope glycoproteins (Env) are the focus of HIV-1 vaccine development strategies based on the induction of humoral immunity, but the mechanisms the virus has evolved to limit the induction and binding of neutralizing antibodies (NAbs) constitute substantial obstacles. Conserved neutralization epitopes are shielded by variable regions and carbohydrates, so one strategy to increase their exposure and, it is hoped, their immunogenicity is to delete the overlying variable loops. However, deleting the variable regions from Env trimers can be problematic, because hydrophobic patches that are normally solvent-inaccessible now become exposed, causing protein misfolding or aggregation, for example. Here, we describe the construction and characterization of recombinant gp140 trimers lacking variable domains 1 and 2 (ΔV1V2). The design of the trimers was guided by HIV-1 evolution studies that identified compensatory changes in V1V2-deleted but functional Env proteins (Bontjer, I., Land, A., Eggink, D., Verkade, E., Tuin, K., Baldwin, C., Pollakis, G., Paxton, W. A., Braakman, I., Berkhout, B., and Sanders, R. W. (2009) J. Virol. 83, 368-383). We now show that specific compensatory changes improved the function of ΔV1V2 Env proteins and hence HIV-1 replication. The changes acted by reducing the exposure of a hydrophobic surface either by replacing a hydrophobic residue with a hydrophilic one or by covering the surface with a glycan. The compensatory changes allowed the efficient expression of well folded, soluble gp140 trimers derived from various HIV-1 isolates. The evolved ΔV1V2 Env viruses were extremely sensitive to NAbs, indicating that neutralization epitopes are well exposed, which was confirmed by studies of NAb binding to the soluble ΔV1V2 gp140 trimers. These evolved ΔV1V2 trimers could be useful reagents for immunogenicity and structural studies.

Alternate JournalJ. Biol. Chem.
PubMed ID20826824
PubMed Central IDPMC2978575
Grant ListAI36082 / AI / NIAID NIH HHS / United States
AI45463 / AI / NIAID NIH HHS / United States

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