This work was supported by core research grants provided to Singapore Immunology Network by the Biomedical Research Council (BMRC), and by the A*ccelerate GAP-funded project (ACCL/19-GAP064-R20H-H)

This work was supported by core research grants provided to Singapore Immunology Network by the Biomedical Research Council (BMRC), and by the A*ccelerate GAP-funded project (ACCL/19-GAP064-R20H-H).. immunoassays for SARS-CoV-2, while discussing the strengths, limitations and applications of antibody detection in SARS-CoV-2 research and control. Keywords: SARS-CoV-2, COVID-19, detection, immunoassays, antibodies, spike, receptor binding domain name, nucleocapsid Introduction The ongoing pandemic, which originates from a newly emerged coronavirus, SARS-CoV-2, was discovered in the city of Wuhan in China’s Hubei province in December 2019 (1). SF3a60 To date, due to quick transmission globally, you will find more than two million laboratory-confirmed human infection RO-1138452 cases, with a few hundred thousand deaths across 210 countries and territories (https://www.who.int/emergencies/diseases/novel-coronavirus-2019/situation-reports/). This unprecedented crisis led to a worldwide effort to rapidly characterize the immunobiology of SARS-CoV-2, while mitigating further spread of this fatal pathogen. SARS-CoV-2 is usually a single stranded, positive sense RNA computer virus that belongs to the family of the genus (2). It has a genome size of ~30 kilobases that encodes for multiple structural proteins comprising the spike (S), the envelope (E), the membrane (M), and the nucleocapsid (N), as well as nonstructural proteins (3) (Physique 1). Contamination by SARS-CoV-2 causes an acute respiratory disease termed the Coronavirus Disease 2019 (COVID-19). The clinical manifestations of COVID-19 form a spectrum, from being asymptomatic to fever with moderate respiratory illness, to acute respiratory distress syndrome, and death from respiratory failure or associated complications (3C5). As the reported incubation period varies among different patient cohorts, it is often hard to ascertain the actual day of onset, and infected subjects who are asymptomatic or pre-symptomatic may go undetected (5C7). Open in a separate window Physique 1 Schematic diagram of SARS-CoV-2 computer virus structure and genome business. (A) The viral surface proteins, spike (S), envelope (E), and membrane (M) are embedded in a lipid bilayer. The single stranded positive-sense viral RNA is usually associated with the nucleocapsid (N) protein. Diagram was created with BioRender. (B) The genome business of RO-1138452 SARS-CoV-2 viral RNA, which is usually adapted from GenBank accession number: MN908947, is usually characterized by sequence alignment against two representative members of the genus. The entire genome sequence is usually ~30 kilobases (kb) long. Early detection of SARS-CoV-2 contamination is one of the crucial interventions to control computer virus transmission. With the discovery of the computer virus, numerous diagnostic assays using quantitative reverse RO-1138452 transcriptase PCR (qRT-PCR) were developed (3). qRT-PCR is the reference standard for diagnosing infections with high sensitivity and accuracy in the Acute phase of illness. SARS-CoV-2 viral RNA has been detected in both throat and nasal swabs of infected individuals by qRT-PCR, which becomes almost undetectable by 14 days RO-1138452 post-illness onset (pio) (or symptom onset) (8, 9) (Physique 2). Apart from being costly and time consuming to perform, false unfavorable results may arise due to improper handling of nucleic acid samples, inadequate and variable sampling resulting in insufficient viral genetic material at the point of detection (after 14 days pio), or biological variance on when viral RNA is usually detectable by qRT-PCR (10, 15). With the limitations of qRT-PCR, immunoassays may offer another avenue to reduce undiagnosed cases, with the advantage that rapid test types may deliver results in a relatively shorter time and lower cost (10). Open in a separate window Physique 2 Schematic illustration around the window period of detection for either viral RNA or antibodies in SARS-CoV-2-infected individuals. Presence of SARS-CoV-2 viral RNA (boxed in pink) in throat or nasal swab of patients are typically undetectable by 14 day post illness onset (pio) (8, 9). SARS-CoV-2-specific antibodies (boxed in blue): IgM is usually detectable as early as 3 days pio, and peaks.