Development of a synthetic nanoparticle vaccine presenting the HIV-1 envelope glycoprotein

Phindile Ximba; Rosamund Chapman; Ann Meyers; Emmanuel Margolin; Michiel T van Diepen; Adam F Sander; Jeremy Woodward; Penny L Moore; Anna-Lise Williamson; Edward P Rybicki

doi:10.1088/1361-6528/ac842c

Development of a synthetic nanoparticle vaccine presenting the HIV-1 envelope glycoprotein

Nanotechnology. 2022 Sep 12;33(48). doi: 10.1088/1361-6528/ac842c.

Authors

Phindile Ximba^{1

2

3}, Rosamund Chapman^{1

3}, Ann Meyers², Emmanuel Margolin^{1

2

3}, Michiel T van Diepen^{1

3}, Adam F Sander⁴, Jeremy Woodward⁵, Penny L Moore^{3

6

7

8}, Anna-Lise Williamson^{1

3}, Edward P Rybicki^{2

3}

Affiliations

¹ Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
² Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Science, University of Cape Town, Cape Town, South Africa.
³ Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
⁴ Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
⁵ Structural Biology Research Unit, University of Cape Town, South Africa.
⁶ National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa.
⁷ MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa.
⁸ Centre for the AIDS Programme of Research in South Africa, Durban, South Africa.

PMID: 35882111
DOI: 10.1088/1361-6528/ac842c

Abstract

Two-component self-assembling virus-like particles (VLPs) are promising scaffolds for achieving high-density display of HIV-1 envelope (gp140) trimers, which can improve the induction of neutralising antibodies (NAbs). In this study gp140 was displayed on the surface of VLPs formed by the AP205 phage coat protein. The CAP256 SU gp140 antigen was selected as the patient who this virus was isolated from developed broadly neutralising antibodies (bNAbs) shortly after superinfection with this virus. The CAP256 SU envelope is also sensitive to several bNAbs and has shown enhanced reactivity for certain bNAb precursors. A fusion protein comprising the HIV-1 CAP256 SU gp140 and the SpyTag (ST) (gp140-ST) was produced in HEK293 cells, and trimers were purified to homogeneity using gel filtration. SpyCatcher (SC)-AP205 VLPs were produced inEscherichia coliand purified by ultracentrifugation. The gp140-ST trimers and the SC-AP205 VLPs were mixed in varying molar ratios to generate VLPs displaying the glycoprotein (AP205-gp140-ST particles). Dynamic light scattering, negative stain electron microscopy and 2D classification indicated that gp140-ST was successfully bound to the VLPs, although not all potential binding sites were occupied. The immunogenicity of the coupled VLPs was evaluated in a pilot study in rabbits. One group was injected four times with coupled VLPs, and the second group was primed with DNA vaccines expressing Env and a mosaic Gag, followed by modified vaccinia Ankara expressing the same antigens. The animals were then boosted twice with coupled VLPs. Encouragingly, gp140-ST displayed on SC-AP205 VLPs was an effective boost to heterologously primed rabbits, leading to induction of autologous Tier 2 neutralising antibodies in 2/5 rabbits. However, four inoculations of coupled VLPs alone failed to elicit any Tier 2 antibodies. These results demonstrate that the native-like structure of HIV-1 envelope trimers and selection of a geometrically-suitable nanoparticle scaffold to achieve a high-density display of the trimers are important considerations that could improve the effect of nanoparticle-displayed gp140.

Keywords: HIV-1 envelope; SpyTag/SpyCatcher; neutralising antibodies; vaccine; virus-like particles.

MeSH terms

Animals
Broadly Neutralizing Antibodies
HEK293 Cells
HIV-1*
Humans
Nanoparticles*
Pilot Projects
Rabbits
Vaccines*
env Gene Products, Human Immunodeficiency Virus / chemistry
env Gene Products, Human Immunodeficiency Virus / genetics

Substances

Broadly Neutralizing Antibodies
Vaccines
env Gene Products, Human Immunodeficiency Virus