bioRxiv ScienceSearch

Biology subjects

Guilligay, D.

Publications and source records attributed to Guilligay, D..

2 recordsLinked to original sources

Immunization with synthetic SARS-CoV-2 S glycoprotein virus-like particles protects Macaques from infection

The SARS-CoV-2 pandemic causes an ongoing global health crisis, which requires efficient and safe vaccination programs. Here, we present synthetic SARS-CoV2 S glycoprotein-coated liposomes that resemble in size and surface structure virus-like particles. Soluble S glycoprotein trimers were stabilized by formaldehyde cross-linking and coated onto lipid vesicles (S-VLP). Immunization of cynomolgus macaques with S-VLPs induced high antibody titers and TH1 CD4+ biased T cell responses. Although antibody responses were initially dominated by RBD specificity, the third immunization boosted non-RBD antibody titers. Antibodies showed potent neutralization against the vaccine strain and the Alpha variant after two immunizations and robust neutralization of Beta and Gamma strains. Challenge of animals with SARS-CoV-2 protected all vaccinated animals by sterilizing immunity. Thus, the S-VLP approach is an efficient and safe vaccine candidate based on a proven classical approach for further development and clinical testing.

immunology

Structure of HIV-1 gp41 with its membrane anchors targeted by neutralizing antibodies

The HIV-1 gp120/gp41 trimer undergoes a series of conformational changes in order to catalyze gp41-induced fusion of viral and cellular membranes. Here, we present the crystal structure of gp41 locked in a fusion intermediate state by an MPER-specific neutralizing antibody. The structure illustrates the conformational plasticity of the six membrane anchors arranged asymmetrically with the fusion peptides and the transmembrane regions pointing into different directions. Hinge regions located adjacent to the fusion peptide and the transmembrane region facilitate the conformational flexibility that allows high affinity binding of broadly neutralizing anti-MPER antibodies. Molecular dynamics simulation of the MPER Ab-induced gp41 conformation reveals the transition into the final post-fusion conformation with the central fusion peptides forming a hydrophobic core with flanking transmembrane regions. This, thus, suggests that MPER-specific broadly neutralizing antibodies can block final steps of refolding of the fusion peptide and the transmembrane region, which is required for completing membrane fusion.

microbiology