Featured COVID-19 Publications

Incucyte® Publications

https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1009165

Mor, M. et al. Multi-clonal SARS-CoV-2 neutralization by antibodies isolated from severe COVID-19 convalescent donors. PLoS Pathog 17(2): e1009165. 2021.

The relationship between antibodies, immune cells and disease severity in SARS-CoV-2 cases is not fully known. This study analyzes the cellular, molecular, and functional features of the antibody response in convalescent blood from severe versus mild SARS-CoV-2 donors. The authors used the Incucyte® S3 Live-Cell Analysis System to monitor cell death and cell-to-cell fusion when using isolated anti-SARS-CoV-2 antibodies. The data showed that severe COVID-19 triggers a unique antibody response and can inform treatment strategies with antibody cocktails.

Key Findings:

  • Donors with severe disease exhibited higher titers of anti-SARS-CoV-2 IgG against spike receptor binding domain (RBD), and higher B-cell expansion.
  • Six out of 22 isolated monoclonal antibodies potently neutralized the live virus and prevented syncytia formation in live-cell assays. Peptide libraries, computational methods and mutagenesis analysis revealed the mechanism of antibody binding.
  • Cocktails of isolated neutralizing antibodies prevented viral replication in cell culture.


https://www.biorxiv.org/content/10.1101/2020.06.17.156455v1.abstract

Stukalov, A. et at. Multi-level proteomics reveals host-perturbation strategies of SARS-CoV-2 and SARS-CoV, 2020. doi: https://doi.org/10.1101/2020.06.17.156455

Developing treatments against SARS-CoV2 requires a better understanding of how viral proteins interact with host proteins. This proteomics study characterizes the viral-host protein-protein interactions and signaling processes that are involved in an infection with SARS-CoV-2 and related coronaviruses. The data revealed unique and common pathways that can be manipulated by known drugs to alter the course of infection with coronaviruses.

Key Findings:

  • Proteomics analysis identified 1,484 interactions between 1,086 cellular proteins and 24 SARS-CoV-2 and 27 SARS-CoV bait proteins, suggesting involvement of a range of biological processes.
  • Combined datasets showed that key pathways such as stress and DNA damage response, and regulation of transcription and cell junction organization were involved in the course of infection.
  • Selective targeting of these pathways using 48 clinically approved compounds identified kinase and matrix metalloproteinase inhibitors with significant antiviral activity against SARS-CoV2. The authors performed the time-lapse fluorescent viral assays using the Incucyte® S3 Live-Cell Analysis System.

iQue® Publications

https://pubmed.ncbi.nlm.nih.gov/33514825/

Dogan, M. et al. SARS-CoV-2 specific antibody and neutralization assays reveal the wide range of the humoral immune response to virus. Commun Biol. 4(1):129. 2021.

Understanding the quantity, quality, and duration of antibody response to COVID-19 is critical for the development of vaccines. This study addresses a major gap in these efforts by developing highly sensitive and specific assays for detecting SARS-CoV-2 antibodies and neutralization. Screening for antibody binding to SARS-CoV-2 proteins was performed on an iQue® system for advanced high throughput flow cytometry. The authors used the assays to demonstrate varied humoral immune responses across COVID-19 patients.

Key Findings:

  • Bead-based fluorescent immunoassay accurately detected SARS-CoV-2 spike protein or nucleocapsid protein specific IgG antibodies at dilutions up to 100,000-fold of plasma samples from SARS-CoV-2 subjects. Other antibody isotypes were also detectable.
  • Robust assay using SARS-CoV-2 spike protein pseudovirus detected neutralization in both COVID-19 and convalescent plasma at up to 10,000-fold dilution.
  • The assays revealed differences in humoral immune response in COVID-19 patients; namely patients with severe disease had 3,000-fold higher antibody and neutralization titers compared to outpatient or convalescent plasma donors.


https://www.sciencedirect.com/science/article/pii/S0022283620306732

Hattori, T. et al. The ACE2-binding Interface of SARS-CoV-2 Spike Inherently Deflects Immune Recognition. J Mol Biol. 433(3):166748. 2021.

A detailed understanding of the immunogenic surfaces on the SARS-CoV-2 spike protein and its receptor binding domain (RBD) is vital for developing potent vaccines and antibody-based treatments. This study utilizes an RBD mutant as tool for characterizing anti-RBD antibodies from convalescent sera of COVID-19 patients. The data showed that the ACE2-interacting surface of the RBD is less immunogenic than other regions. The authors used the iQue® system for advanced high throughput flow cytometry to perform cell- and bead-based binding assays.

Key Findings:

  • Binding analysis of antibodies in convalescent sera showed that most antibodies did not target the ACE2-interacting surface of RBD.  
  • An unbiased in vitro antibody selection using a human antibody phage display library showed that 89% of the clones bound the spike protein, but not the RBD or the ACE2-binding surface. The biased screen identified antibodies that targeted the ACE2-binding surface.
  • The antibodies that bound RBD in an unbiased selection, preferentially bound the surfaces that are not exposed in the native spike protein trimer.