Multivalent display of engineered HIV-1 envelope trimers on silica nanoparticles for targeting and in vitro activation of germline VRC01 B cells

David Peterhoff; Stefanie Thalhauser; Patrick Neckermann; Clara Barbey; Kristina Straub; Julian Nazet; Rainer Merkl; Gernot Laengst; Miriam Breunig; Ralf Wagner

doi:10.1016/j.ejpb.2022.10.007

Multivalent display of engineered HIV-1 envelope trimers on silica nanoparticles for targeting and in vitro activation of germline VRC01 B cells

Eur J Pharm Biopharm. 2022 Dec:181:88-101. doi: 10.1016/j.ejpb.2022.10.007. Epub 2022 Oct 19.

Authors

Affiliations

¹ Institute of Medical Microbiology and Hygiene, Molecular Microbiology (Virology), University of Regensburg, 93040 Regensburg, Germany; Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, 93053 Regensburg, Germany. Electronic address: david.peterhoff@ur.de.
² Department of Pharmaceutical Technology, University of Regensburg, 93040 Regensburg, Germany.
³ Institute of Medical Microbiology and Hygiene, Molecular Microbiology (Virology), University of Regensburg, 93040 Regensburg, Germany.
⁴ Regensburg Center for Biochemistry, University of Regensburg, 93040 Regensburg, Germany.
⁵ Department of Pharmaceutical Technology, University of Regensburg, 93040 Regensburg, Germany. Electronic address: miriam.breunig@ur.de.
⁶ Institute of Medical Microbiology and Hygiene, Molecular Microbiology (Virology), University of Regensburg, 93040 Regensburg, Germany; Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, 93053 Regensburg, Germany. Electronic address: ralf.wagner@ur.de.

PMID: 36272655
DOI: 10.1016/j.ejpb.2022.10.007

Abstract

Selective targeting of germline B cells with specifically designed germline-targeting HIV-1 envelope immunogens (GT-Env) is considered a feasible vaccination strategy to elicit broadly neutralizing antibodies (bnAbs). BnAbs are extremely valuable because they neutralize genetically distant viral strains at the same time. To overcome its inherently low affinity to germline B cells, the aim of the study was to present GT-Env via different immobilization strategies densely arrayed on the surface of nanoparticles. We engineered a prefusion-stabilized GT-Env trimer with affinity to VRC01 germline B cells using a bioinformatics-supported design approach. Distinct glycan modifications and amino acid substitutions yielded a GT-Env trimer which bound to the receptor with a K_D of 11.5 µM. Silica nanoparticles with 200 nm diameter (SiNPs) were used for the multivalent display of the novel GT-Env with a 15 nm mean centre-to-centre spacing either by site-specific, covalent conjugation or at random, non-specific adsorption. Oriented, covalent GT-Env conjugation revealed better binding of structure dependent bnAbs as compared to non-specifically adsorbed GT-Env. In addition, GT-Env covalently attached activated a B cell line expressing the germline VRC01 receptor at an EC₅₀ value in the nanomolar range (4 nM), while soluble GT-Env required 1,000-fold higher concentrations to induce signalling. The significantly lower GT-Env concentration was likely required due to avidity effects, which were in the picomolar range. Thus, low affinity antigens may particularly benefit from a particulate and multivalent delivery. In future, SiNPs are ideal to be modified in a modular design with various GT-Env variants that target different stages of germline and bnAb precursor B cells.

Keywords: Affinity; Avidity; B cells; Env; Germline-targeting; HIV-1; Immunogen design; Multivalent interaction; Nanotechnology; Silica nanoparticles; Vaccine.

MeSH terms

HIV-1*
Silicon Dioxide*

Substances

Silicon Dioxide