SARS-CoV-2 Spike "donor" cells for cell fusion assays

HEK293-derived "donor" cell line for Spike-dependent cell fusion

InvivoGen offers a human embryonic kidney (HEK)293-derived cell line, specifically designed to study SARS-CoV-2-host cell fusion:

• 293-hMyD88 Cells

These cells have been engineered to express a constitutively active human MyD88 [1]. Upon transient transfection, with a Spike expression plasmid, 293 hMyD88 cells become a SARS-CoV-2 mimic, which can then fuse with InvivoGen's permissive reporter cells (e.g. HEK Blue™ hACE2-TMPRSS2 and A549 Dual™ hACE2 TMPRSS2) [2].

More details

Rationale

SARS-CoV-2 variants are characterized by several mutations within the antigenic Spike protein, which drives the virus entry into target cells [3]. These mutations provide a selective advantage to the virus, ultimately reducing the effectiveness of vaccination and therapeutic strategies [4]. Thus, Spike-mediated SARS-CoV-2 fusion with target cells is a relevant readout to screen for novel neutralizing monoclonal antibodies (mAbs) or small molecule inhibitors.

InvivoGen has developed a simple cell fusion assay that relies on the transfer of the adaptor molecule, MyD88, from a 'donor cell line' to an 'acceptor cell line' expressing an NF-κB-SEAP-inducible reporter gene. Cell fusion is readily assessable in the co-culture supernatant using the SEAP detection reagent, QUANTI-Blue™ Solution.

Learn more about InvivoGen's cell fusion assays
 

Key Features

• Stable and constitutive activation of the human MyD88 gene for NF-κB-SEAP-based cell fusion assays.
• Functionally validated in cell fusion assays using pUNO1-Spike (Wuhan-Hu-1 D614) and the HEK-Blue™ hACE2(-TMPRSS2) reporter cell line.
   

Applications

• Screening inhibitors of Spike-binding and/or SARS-CoV-2 host receptors.
• Studying the efficacy of vaccination and current therapeutics against emerging SARS-CoV-2 variants.

➔ 293-hMyD88 cells with stable expression of Spike (Wuhan, original), Spike V8 (Delta/B.1.617,2), or Spike V11 (Omicron/BA.1) have also been generated. These cells have been used to compare the efficiency of EK1C4 at inhibiting SARS-CoV2 Spike variant-mediated cellular fusion. See data

Learn more about emerging SARS-CoV-2 variants

References:

1. Deguine J. & Barton G.M. 2014. MyD88: a central player in innate immune signaling. F1000Prime Reports, 6:97, doi:10.12703/P6-97
2. Hoffmann M. et al. 2020. SARS-CoV-2 cell entry depends on ACE2 and TMPRSS2 and is blocked by a clinically proven protease inhibitor. Cell. 181:1-16.
3. Garcia-Beltran, W.F. et al. 2021. Multiple SARS-CoV-2 variants escape neutralization by vaccine-induced humoral immunity. Cell. doi:10.1016/j.cell.2021.03.013
4. Greaney, A.J. et al., 2021. Complete mapping of mutations to the SARS-CoV-2 spike receptor-binding domain that escapes antibody recognition. Cell Host & Microbe. DOI: 10.1016/j.chom.2020.11.007.