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S309-CAR-NK cells bind the Omicron variants in vitro and reduce SARS-CoV-2 viral loads in humanized ACE2-NSG mice
Minh Tuyet Ma1,2,3, Qingkui Jiang4, Chih-Hsiung Chen1,3
1Department of Pathology, Immunology, and Laboratory Medicine, South Orange Avenue, Newark, New Jersey, USA.
Abstract:
Recent progress on chimeric antigen receptor (CAR)-NK cells has shown promising results in treating CD19-positive lymphoid tumors with minimal toxicities [including graft versus host disease (GvHD) and cytokine release syndrome (CRS) in clinical trials. Nevertheless, the use of CAR-NK cells in combating viral infections has not yet been fully explored. Previous studies have shown that CAR-NK cells expressing S309 single-chain fragment variable (scFv), hereinafter S309-CAR-NK cells, can bind to SARS-CoV-2 wildtype pseudotyped virus (PV) and effectively kill cells expressing wild-type spike protein in vitro. In this study, we further demonstrate that the S309-CAR-NK cells can bind to different SARS-CoV-2 variants, including the B.1.617.2 (Delta), B.1.621 (Mu), and B.1.1.529 (Omicron) variants in vitro. We also show that S309-CAR-NK cells reduce virus loads in the NOD/SCID gamma (NSG) mice expressing the human angiotensin-converting enzyme 2 (hACE2) receptor challenged with SARS-CoV-2 wild-type (strain USA/WA1/2020). Our study demonstrates the potential use of S309-CAR-NK cells for inhibiting infection by SARS-CoV-2 and for the potential treatment of COVID-19 patients unresponsive to otherwise currently available therapeutics.
Importance:
Chimeric antigen receptor (CAR)-NK cells can be "off-the-shelf" products that treat various diseases, including cancer, infections, and autoimmune diseases. In this study, we engineered natural killer (NK) cells to express S309 single-chain fragment variable (scFv), to target the Spike protein of SARS-CoV-2, hereinafter S309-CAR-NK cells. Our study shows that S309-CAR-NK cells are effective against different SARS-CoV-2 variants, including the B.1.617.2 (Delta), B.1.621 (Mu), and B.1.1.529 (Omicron) variants. The S309-CAR-NK cells can (i) directly bind to SARS-CoV-2 pseudotyped virus (PV), (ii) competitively bind to SARS-CoV-2 PV with 293T cells expressing the human angiotensin-converting enzyme 2 (hACE2) receptor (293T-hACE2 cells), (iii) specifically target and lyse A549 cells expressing the spike protein, and (iv) significantly reduce the viral loads of SARS-CoV-2 wild-type (strain USA/WA1/2020) in the lungs of NOD/SCID gamma (NSG) mice expressing hACE2 (hACE2-NSG mice). Altogether, the current study demonstrates the potential use of S309-CAR-NK immunotherapy as an alternative treatment for COVID-19 patients.
Insights
Engineered chimeric antigen receptor (CAR)-NK cells targeting the SARS-CoV-2 spike protein show effectiveness against multiple COVID-19 variants. These S309-CAR-NK cells reduce viral loads in mice, indicating potential for treating COVID-19 patients.
Area of Science:
- Immunotherapy
- Virology
- Cellular Engineering
Background:
- Chimeric antigen receptor (CAR)-NK cells show promise for treating various diseases, including cancers and infections.
- Previous research demonstrated CAR-NK cells targeting SARS-CoV-2 spike protein can bind pseudotyped virus and kill infected cells.
- The efficacy of CAR-NK cells against emerging SARS-CoV-2 variants and in vivo viral infections remains to be fully elucidated.
Purpose of the Study:
- To engineer and evaluate natural killer (NK) cells expressing S309 single-chain fragment variable (scFv) for targeting the SARS-CoV-2 spike protein (S309-CAR-NK cells).
- To assess the binding capabilities of S309-CAR-NK cells against different SARS-CoV-2 variants.
- To determine the therapeutic potential of S309-CAR-NK cells in reducing SARS-CoV-2 viral loads in a preclinical mouse model.
Main Methods:
- Engineered human NK cells to express S309-CAR, targeting the SARS-CoV-2 spike protein.
- Assessed S309-CAR-NK cell binding to SARS-CoV-2 pseudotyped virus (PV) and spike protein-expressing cells in vitro.
- Evaluated S309-CAR-NK cell efficacy in reducing viral loads in hACE2-expressing NSG mice challenged with SARS-CoV-2.
Main Results:
- S309-CAR-NK cells demonstrated binding to SARS-CoV-2 PV and effectively lysed target cells expressing the spike protein.
- S309-CAR-NK cells exhibited binding to multiple SARS-CoV-2 variants, including Delta, Mu, and Omicron.
- In vivo studies showed S309-CAR-NK cells significantly reduced SARS-CoV-2 viral loads in the lungs of infected hACE2-NSG mice.
Conclusions:
- S309-CAR-NK cells are effective against various SARS-CoV-2 variants and demonstrate in vivo antiviral activity.
- This study highlights the potential of S309-CAR-NK cell immunotherapy as a novel therapeutic strategy for COVID-19.
- S309-CAR-NK cells offer a promising 'off-the-shelf' treatment option for patients unresponsive to current therapies.
