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Kruse RL, Huang Y, Smetana H, Gehrie EA, Amukele TK, Tobian AA, Mostafa HH, Wang ZZ. A rapid, point-of-care red blood cell agglutination assay detecting antibodies against SARS-CoV-2. Biochem Biophys Res Commun 2021; 553:165-171. [PMID: 33773139 PMCID: PMC7959259 DOI: 10.1016/j.bbrc.2021.03.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/03/2021] [Indexed: 01/08/2023]
Abstract
The COVID-19 pandemic has caused significant morbidity and mortality. There is an urgent need for serological tests to detect antibodies against SARS-CoV-2, which could be used to assess past infection, evaluate responses to vaccines in development, and determine individuals who may be protected from future infection. Current serological tests developed for SARS-CoV-2 rely on traditional technologies such as enzyme-linked immunosorbent assays (ELISA) and lateral flow assays, which have not scaled to meet the demand of hundreds of millions of antibody tests so far. Herein, we present an alternative method of antibody testing that depends on one protein reagent being added to patient serum/plasma or whole blood with direct, visual readout. Two novel fusion proteins, RBD-2E8 and B6-CH1-RBD, were designed to bind red blood cells (RBCs) via a single-chain variable fragment (scFv), thereby displaying the receptor-binding domain (RBD) of SARS-CoV-2 spike protein on the surface of RBCs. Mixing mammalian-derived RBD-2E8 and B6-CH1-RBD with convalescent COVID-19 patient serum and RBCs led to visible hemagglutination, indicating the presence of antibodies against SARS-CoV-2 RBD. B6-CH1-RBD made in bacteria was not as effective in inducing agglutination, indicating better recognition of RBD epitopes from mammalian cells. Given that our hemagglutination test uses methods routinely used in hospital clinical labs across the world for blood typing, we anticipate the test can be rapidly deployed at minimal cost. We anticipate our hemagglutination assay may find extensive use in low-resource settings for detecting SARS-CoV-2 antibodies.
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Affiliation(s)
- Robert L. Kruse
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Corresponding author. Carnegie Building, Room 401, Johns Hopkins Hospital, 600N Wolfe St, Baltimore, MD, 21287, USA
| | - Yuting Huang
- Department of Medicine, University of Maryland Medical Center Midtown Campus, Baltimore, MD, USA,Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Heather Smetana
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Eric A. Gehrie
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Timothy K. Amukele
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Aaron A.R. Tobian
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Heba H. Mostafa
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zack Z. Wang
- Division of Hematology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Corresponding author
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Approaches for the development of rapid serological assays for surveillance and diagnosis of infections caused by zoonotic flaviviruses of the Japanese encephalitis virus serocomplex. J Biomed Biotechnol 2012; 2012:379738. [PMID: 22570528 PMCID: PMC3337611 DOI: 10.1155/2012/379738] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 01/24/2012] [Accepted: 01/29/2012] [Indexed: 11/17/2022] Open
Abstract
Flaviviruses are responsible for a number of important mosquito-borne diseases of man and animals globally. The short vireamic period in infected hosts means that serological assays are often the diagnostic method of choice. This paper will focus on the traditional methods to diagnose flaviviral infections as well as describing the modern rapid platforms and approaches for diagnostic antigen preparation.
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Toward low-cost affinity reagents: lyophilized yeast-scFv probes specific for pathogen antigens. PLoS One 2012; 7:e32042. [PMID: 22363793 PMCID: PMC3282784 DOI: 10.1371/journal.pone.0032042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 01/18/2012] [Indexed: 11/25/2022] Open
Abstract
The generation of affinity reagents, usually monoclonal antibodies, remains a critical bottleneck in biomedical research and diagnostic test development. Recombinant antibody-like proteins such as scFv have yet to replace traditional monoclonal antibodies in antigen detection applications, in large part because of poor performance of scFv in solution. To address this limitation, we have developed assays that use whole yeast cells expressing scFv on their surfaces (yeast-scFv) in place of soluble purified scFv or traditional monoclonal antibodies. In this study, a nonimmune library of human scFv displayed on the surfaces of yeast cells was screened for clones that bind to recombinant cyst proteins of Entamoeba histolytica, an enteric pathogen of humans. Selected yeast-scFv clones were stabilized by lyophilization and used in detection assay formats in which the yeast-scFv served as solid support-bound monoclonal antibodies. Specific binding of antigen to the yeast-scFv was detected by staining with rabbit polyclonal antibodies. In flow cytometry-based assays, lyophilized yeast-scFv reagents retained full binding activity and specificity for their cognate antigens after 4 weeks of storage at room temperature in the absence of desiccants or stabilizers. Because flow cytometry is not available to all potential assay users, an immunofluorescence assay was also developed that detects antigen with similar sensitivity and specificity. Antigen-specific whole-cell yeast-scFv reagents can be selected from nonimmune libraries in 2–3 weeks, produced in vast quantities, and packaged in lyophilized form for extended shelf life. Lyophilized yeast-scFv show promise as low cost, renewable alternatives to monoclonal antibodies for diagnosis and research.
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