Integrity of Glycosylation Processing of a Glycan-Depleted Trimeric HIV‑1 Immunogen Targeting Key B‑Cell Lineages
journal contributionposted on 2018-02-08, 18:03 authored by Anna-Janina Behrens, Abhinav Kumar, Max Medina-Ramirez, Albert Cupo, Kevin Marshall, Victor M. Cruz Portillo, David J. Harvey, Gabriel Ozorowski, Nicole Zitzmann, Ian A. Wilson, Andrew B. Ward, Weston B. Struwe, John P. Moore, Rogier W. Sanders, Max Crispin
Broadly neutralizing antibodies (bNAbs) that target the trimeric HIV-1 envelope glycoprotein spike (Env) are tools that can guide the design of recombinant Env proteins intended to engage the predicted human germline precursors of bNAbs (gl-bNAbs). The protein components of gl-bNAb epitopes are often masked by glycans, while mature bNAbs can evolve to accommodate or bypass these shielding glycans. The design of germline-targeting Env immunogens therefore includes the targeted deletion of specific glycan sites. However, the processing of glycans on Env trimers can be influenced by the density with which they are packed together, a highly relevant point given the essential contributions under-processed glycans make to multiple bNAb epitopes. We sought to determine the impact of the removal of 15 potential N-glycan sites (5 per protomer) from the germline-targeting soluble trimer, BG505 SOSIP.v4.1-GT1, using quantitative, site-specific N-glycan mass spectrometry analysis. We find that, compared with SOSIP.664, there was little overall change in the glycan profile but only subtle increases in the extent of processing at sites immediately adjacent to where glycans had been deleted. We conclude that multiple glycans can be deleted from BG505 SOSIP trimers without perturbing the overall integrity of the glycan shield.
Read the peer-reviewed publication
envelope glycoprotein spikesite-specific N-glycan mass spectrometry analysisGlycosylation Processingprotein componentsgermline-targeting Env immunogensBG 505 SOSIP.v 4.1-GTtrimeric HIVneutralizing antibodiesEnv proteinscontributions under-processed glycansEnv trimersglycan profilegermline precursorsgl-bNAb epitopesBG 505 SOSIP trimersglycan shieldshielding glycansglycan sitesbNAb epitopes