A flow cytometry-based assay for serological detection of anti-spike antibodies in COVID-19 patients

Abstract

One of the key public health strategies in coronavirus 2019 disease (COVID-19) management is the early detection of infected individuals to limit the transmission. As a result, serological assays have been developed to complement PCR-based assays. Here, we report the development of a flow cytometry-based assay to detect antibodies against full-length SARS-CoV-2 spike protein (S protein) in patients with COVID-19. The assay is time-efficient and sensitive, being able to capture the wider repertoire of antibodies against the S protein. For complete details on the use and execution of this protocol, please refer to Goh et al. (2021).

Keywords: Antibody; Cell Biology; Flow Cytometry/Mass Cytometry; Health Sciences; Immunology; Molecular Biology.

Graphical abstract

Figure 1

Plasmid map of pHIV-eGFP S gene is inserted between the XbaI and BamHI sites.

Figure 2

FACS plot analysis Cells were gated on: (A) FSC-A/SSC-A to exclude cell debris, (B) FSC-A/FSC-H to select for single cells, (C) FSC-H/PI to select for live cells (PI-negative population), (D, E) FITC/Alexa Fluor 647 for specific antibody binding. Binding is determined by the percentage of GFP-positive S protein-expressing cells that are bound by specific antibody, indicated by the events that are Alexa Fluor 647- and FITC-positive (Gate 2). (D) PBS control; (E) COVID-19 patient plasma, 1:100 diluted.