Introduction
Long-term protection from infectious agents, such as the SARS-CoV-2 virus, is mediated by T cells and antibody-mediated immunity of the adaptive immune system (
). The T-SPOT.COVID test was developed to identify the presence of SARS-CoV-2-responsive T cells.
T cells contribute to the understanding of SARS-CoV-2 infections in many ways. T cells can identify past SARS-CoV-2 infections at a time when PCR tests would be negative and antibodies levels may be waning (
;
;
). T cells can provide immune memory lasting for months (
) and perhaps years, as suggested by the discovery of T cells to the SARS-CoV-1 coronavirus 17 years after infection (
). T cells may act independently of antibodies to control a SARS-CoV-2 infection, as shown by the recovery of COVID-19 patients who lack detectable antibodies but have SARS-CoV-2-responsive T cells (
;
). T cells also show reactivity to numerous SARS-CoV-2 epitopes, so have the potential to protect against many SARS-CoV-2 variants (
;
). T cell-based assays can probe the longevity of an immune response following a SARS-CoV-2 infection or vaccination (
;
;
). These various roles suggest that a T cell assay can be a key contributor to SARS-CoV-2 investigations.
The T-SPOT.COVID test, an enzyme-linked immunospot (ELISpot) assay, identifies T cells in peripheral blood that release interferon-gamma (IFN-γ) in response to stimulation with SARS-CoV-2 peptides. The T-SPOT.COVID test builds on the T-SPOT platform (Oxford Immunotec) used worldwide for tuberculosis and cytomegalovirus testing and the research version, the T-SPOT Discovery SARS-CoV-2 test (
HIGHLIGHTS
- •
TSPOT.COVID is an ELISpot interferon gamma-release assay for SARS-CoV-2
- •
TSPOT.COVID identifies a T cell response to SARS-CoV-2 spike S1 and N peptides
- •
2–8 weeks post SARS-CoV-2 diagnosis TSPOT.COVID detected 98% of infections
- •
In comparison, immunoglobulin G (IgG) serology detected 83% of infections in the same period
- •
Cellular immune response activated sooner and lasted longer than antibodies
Abstract
Objective
Methods
Results
Conclusion
). The T-SPOT.COVID ELISpot methodology is performed in many laboratories and offers a standardized comparison of T cell immunity among participants. In addition, ELISpot assays normalize the number of peripheral blood mononuclear cells (PBMCs), thus maintaining test effectiveness in participants with lymphopenia, a commonly reported condition in many COVID-19 patients (
) and immunosuppressed people.
Materials and Methods
2.1 Participant recruitment
Confirmed-infection group: A NAAT, which detects the presence of the SARS-CoV-2 virus, was used to identify people infected with SARS-CoV-2 at the time of testing (
). Participants in the confirmed-infection group were recruited from asymptomatic and symptomatic patients who had had a positive SARS-CoV-2 NAAT result within the past 9 months. The date of the first positive NAAT result was considered the date of diagnosis of SARS-CoV-2 infection. Blood was drawn for Abbott SARS-CoV-2 chemiluminescent microparticle immunoassay (CMIA) anti-N IgG serology and T-SPOT.COVID tests between 0 to 249 days after diagnosis.
2.2 T-SPOT.COVID test
COVID-19 Spike Antigen |
|||
30-2019 | Fitzgerald | 1 mg | EUR 400 |
Description: COVID-19 Spike recombinant antigen |
Moderna COVID-19 Vaccine |
|||
H7N7-319 | Creative BioMart | 1 vial | EUR 798.4 |
Description: Protein |
SARS & COVID-19 coronavirus |
|||
3862 | Virostat | each | EUR 330 |
Description: nucleoprotein |
SARS & COVID-19 coronavirus |
|||
3863 | Virostat | each | EUR 330 |
Description: nucleoprotein |
SARS & COVID-19 coronavirus |
|||
3864 | Virostat | each | EUR 330 |
Description: nucleoprotein |
COVID-19 Negative Control |
|||
MBS412771-05mL | MyBiosource | 0.5mL | EUR 100 |
COVID-19 Negative Control |
|||
MBS412771-5x05mL | MyBiosource | 5x0.5mL | EUR 305 |
Coronavirus COVID-19 Spike (COVID-19, SARS-CoV-2, 2019-nCoV) ELISA Kit |
|||
MBS7612502-10x96StripWells | MyBiosource | 10x96-Strip-Wells | EUR 3900 |
Coronavirus COVID-19 Spike (COVID-19, SARS-CoV-2, 2019-nCoV) ELISA Kit |
|||
MBS7612502-48StripWells | MyBiosource | 48-Strip-Wells | EUR 340 |
Coronavirus COVID-19 Spike (COVID-19, SARS-CoV-2, 2019-nCoV) ELISA Kit |
|||
MBS7612502-5x96StripWells | MyBiosource | 5x96-Strip-Wells | EUR 2045 |
Coronavirus COVID-19 Spike (COVID-19, SARS-CoV-2, 2019-nCoV) ELISA Kit |
|||
MBS7612502-96StripWells | MyBiosource | 96-Strip-Wells | EUR 455 |
COVID-19 S Protein / (GFP)– (6His) VLP COVID-19 S Protein / (GFP)– (6His) VLP |
|||
VLP001 | GenTarget | 1x108 VP/ml x 200ul | EUR 455 |
Description: COVID-19 Spike protein (S) Virus Like Particle, packaged with GFP genomic material. Particles were concentrated and provided in PBS solution |
COVID-19 Nucleocapsid protein |
|||
30-2005 | Fitzgerald | 1 mg | EUR 700 |
Description: COVID-19 Nucleocapsid protein recombinant antigen |
COVID-19 Nucleocapsid protein |
|||
30-2006 | Fitzgerald | 1 mg | EUR 700 |
Description: COVID-19 Nucleocapsid protein recombinant Antigen |
COVID-19 Nucleocapsid antigen |
|||
30-2020 | Fitzgerald | 1 mg | EUR 400 |
Description: COVID-19 Nucleocapsid recombinant protein |
COVID-19 Nucleocapsid antigen |
|||
30-2021 | Fitzgerald | 1 mg | EUR 400 |
Description: COVID-19 Nucleocapsid recombinant protein |
Coronavirus (COVID-19) Antibody |
|||
MBS569951-1mg | MyBiosource | 1mg | EUR 655 |
Coronavirus (COVID-19) Antibody |
|||
MBS569951-5x1mg | MyBiosource | 5x1mg | EUR 2760 |
COVID-19 Nucleocapsid Protein |
|||
MBS669369-005mg | MyBiosource | 0.05mg | EUR 500 |
COVID-19 Nucleocapsid Protein |
|||
MBS669369-025mg | MyBiosource | 0.25mg | EUR 1010 |
COVID-19 Nucleocapsid Protein |
|||
MBS669369-5x025mg | MyBiosource | 5x0.25mg | EUR 4525 |
COVID-19 Nucleoprotein antibody |
|||
10-2890 | Fitzgerald | 1 mg | EUR 420 |
Description: Purified COVID-19 Nucleoprotein Antibody |
COVID-19 Nucleoprotein antibody |
|||
10-2891 | Fitzgerald | 1 mg | EUR 420 |
Description: Purified COVID-19 Nucleoprotein Antibody |
COVID-19 Nucleoprotein antibody |
|||
10-2894 | Fitzgerald | 1 mg | EUR 420 |
Description: Purified COVID-19 Nucleoprotein Antibody |
COVID-19 Nucleoprotein antibody |
|||
MBS5316694-1mg | MyBiosource | 1mg | EUR 360 |
COVID-19 Nucleoprotein antibody |
|||
MBS5316694-5x1mg | MyBiosource | 5x1mg | EUR 1480 |
COVID-19 Nucleoprotein antibody |
|||
MBS5316695-1mg | MyBiosource | 1mg | EUR 360 |
COVID-19 Nucleoprotein antibody |
|||
MBS5316695-5x1mg | MyBiosource | 5x1mg | EUR 1480 |
STAT-NAT COVID-19 B |
|||
BSV-qPCR-12 | BioServUK | 24 tests | EUR 316 |
Description: STAT-NAT COVID-19 B |
STAT-NAT COVID-19 HK |
|||
BSV-qPCR-13 | BioServUK | 24 tests | EUR 316 |
Description: STAT-NAT COVID-19 HK |
COVID-19 Spike ELISA Kit |
|||
MBS7608267-10x96StripWells | MyBiosource | 10x96-Strip-Wells | EUR 3900 |
COVID-19 Spike ELISA Kit |
|||
MBS7608267-48StripWells | MyBiosource | 48-Strip-Wells | EUR 340 |
COVID-19 Spike ELISA Kit |
|||
MBS7608267-5x96StripWells | MyBiosource | 5x96-Strip-Wells | EUR 2045 |
COVID-19 Spike ELISA Kit |
|||
MBS7608267-96StripWells | MyBiosource | 96-Strip-Wells | EUR 455 |
STAT-NAT COVID-19 MULTI |
|||
BSV-qPCR-11 | BioServUK | 96 tests | EUR 758 |
Description: STAT-NAT COVID-19 MULTI |
COVID-19 IgG & IgM antibody |
|||
GEN-50001-50tests | Ring Bio | 50 tests | EUR 388.8 |
Description: A rapid test for detection of antibodies (IgG and IgM) for 2019-nCoV, the novel Coronavirus from the Wuhan strain. The test is easy to perform, takes 10 minutes to provide reliable results and is higly specific to the 2019-nCoV Coronavirus. |