Functional assessments of SARS-CoV-2 single-round infectious particles with variant-specific spike proteins on infectivity, drug sensitivity, and antibody neutralization

Antiviral Res. 2023 Dec:220:105744. doi: 10.1016/j.antiviral.2023.105744. Epub 2023 Nov 7.

Abstract

Working with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is restricted to biosafety level III (BSL-3) laboratory. The study used a trans-complementation system consisting of virus-like particles (VLPs) and DNA-launched replicons to generate SARS-CoV-2 single-round infectious particles (SRIPs) with variant-specific spike (S) proteins. S gene of Wuhan-Hu-1 strain (SWH1) or Omicron BA.1 variant (SBA.1), along with the envelope (E) and membrane (M) genes, were cloned into a tricistronic vector, co-expressed in the cells to produce variant-specific S-VLPs. Additionally, the replicon of the WH1-like strain without S, E, M and accessory genes, was engineered under the control by a CMV promoter to produce self-replicating RNAs within VLP-producing cells, led to create SWH1- and SBA.1-based SARS-CoV-2 SRIPs. The SBA.1-based SRIP showed lower virus yield, replication, N protein expression, fusogenicity, and infectivity compared to SWH1-based SRIPs. SBA.1-based SRIP also exhibited intermediate resistance to neutralizing antibodies produced by SWH1-based vaccines, but were effective at infecting cells with low ACE2 expression. Importantly, both S-based SRIPs responded similarly to remdesivir and GC376, with EC50 values ranging from 0.17 to 1.46 μM, respectively. The study demonstrated that this trans-complementation system is a reliable and efficient tool for generating SARS-CoV-2 SRIPs with variant-specific S proteins. SARS-CoV-2 SRIPs, mimicking authentic live viruses, facilitate comprehensive analysis of variant-specific virological characteristics, including antibody neutralization, and drug sensitivity in non-BSL-3 laboratories.

Keywords: ACE2; Antibody neutralization; Drug sensitivity; Replicon; SARS-CoV-2; Single-round infectious particle; Spike; Variant; Virus yield; Virus-like particle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Neutralizing
  • Antibodies, Viral
  • COVID-19*
  • Humans
  • SARS-CoV-2 / metabolism
  • Spike Glycoprotein, Coronavirus

Substances

  • spike protein, SARS-CoV-2
  • Spike Glycoprotein, Coronavirus
  • Antibodies, Neutralizing
  • Antibodies, Viral