Artist’s rendition of SARS-CoV-2 with Spike Proteins

Serology assays enable researchers to determine if subjects have already been infected with severe acute respiratory coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, by measuring the presence of antibodies against SARS-CoV-2 in blood (serum or plasma). Detectable anti-SARS-CoV-2 antibodies is dependent on the immune response and can be influenced by a variety of factors including dose of virus exposure, assessment stage post-symptom onset, age, gender, and health status. Therefore, specific and sensitive serological assays are important for accurate and reliable detection of anti-SARS-CoV-2 antibodies.

Order now

This ProcartaPlex Human Coronavirus Variants Neutralizing Ab 6-plex panel enables direct comparison of the neutralizing potential of antibodies towards the original wild type virus and four variants, namely B.1.1.529 (o), B.1.1.7 (α), B.1.351 (β), P.1 (γ), and B.1.617.2 (δ), in a single well using Luminex xMAP technology.

ELISA Assay kit

Order now

Invitrogen offers a number of SARS-CoV-2 ELISA kits to measure Ig antibodies, neutralization antibodies and viral-related proteins.

ProcartaPlex Assay kit

Order now

This ProcartaPlex Human Coronavirus Ig Total 11-plex panel enables the detection of multiple anti-SARS-CoV-2 (Spike trimer, S1, RBD, N) Ig antibodies and 6 other coronavirus strains in human serum, helping to provide a more complete antibody profile.

SARS-CoV-2 multiplex serology assays

ProcartaPlex Ig Total (Up to 15-plex including variants)

The proteins that serve as primary antigens to stimulate an immune response producing IgA, IgM, and IgG antibodies during SARS-CoV-2 infection include the nucleocapsid (N), the spike (S) protein, and sub-regions of the spike protein such as the receptor binding domain (RBD) and the S1 regions. The Nucleocapsid (N) protein has the highest homology (90%) between SARS-CoV-1 and SARS-CoV-2 (1). Serology test kits available during the early phase of the SARS-CoV-2 pandemic were developed to detect antibodies against the Nucleocapsid, which displayed significant cross-reactivity, and thus higher false positive readings for subjects exposed to SARS-CoV-1 (1). The SARS-CoV spike (S) protein assembles into a trimerized structure to form a crown-like (hence corona) appearance and is composed of a S1 and S2 subunit. Within S1, the receptor binding domain (RBD), which is located in the C-terminal subdomain, has higher identity (74%) between SARS-CoV and SARS-CoV-2 than the N-terminal domain, consistent with the view that SARS-CoV-2 may use ACE2 as its receptor for entry into host cells like SARS-CoV (2). The RBD has been identified as one of the immunodominant sites of the SARS-CoV-2 spike protein, with antibodies against the spike protein correlating well with neutralization. In addition, it is important to test serologic cross-reactivity with endemic and seasonal coronaviruses to rule out false-positive results. The Human Coronavirus Ig Total 11-Plex ProcartaPlex Panel enables screening of four SARS-CoV-2 antibodies (Spike trimer, S1 subunit, RBD, and Nucleocapsid), six coronavirus strains (SARS-CoV-1, MERS, CoV-NL63, CoV-KHU1, CoV-229E, CoV-OC43), and one negative control in a single well using Luminex xMAP technology. 

In addition, four variants can be plexed with this 11-plex panel to create a 15-plex assay. The four variant proteins include the variants originating from the UK (B.1.1.7) α, South Africa (B.1.351) β, Brazil (P.1) γ, and the delta variant (B.1.617.2). Simultaneous detection of anti-SARS-CoV-2 antibodies and related coronavirus antibodies in one assay can save time to provide a complete, holistic data set using plasma or serum samples.

Neutralizing Antibody 6-plex Panel

The Human SARS-CoV-2 Variants Neutralizing Antibody 6-Plex ProcartaPlex Panel enables screening of six neutralizing anti-SARS-CoV-2 antibodies—original wild-type and five variants B.1.1.529 (o), B.1.617.2 (δ), P.1 (γ), B.1.351 (β), and B.1.1.7 (α) in a single well. This serological assay is designed with SARS-CoV-2 wild type or variant proteins conjugated to the bead. Samples or controls are added where neutralizing antibodies will bind to the proteins. This is a competitive assay where the detector antibody is a biotinylated ACE-2 that will bind to any unbound protein. Streptavidin-phycoerythrin (PE) is added and the signal is indirectly proportional to the amount of specific neutralizing antibody present. Negative controls will give the highest MFI values.

Omicron (B.1.1.529)

In addition to the Neutralizing Antibody 6-Plex panel, there is also a Human SARS-CoV-2 Spike Omicron (B.1.1.529) Neutralizing Ab Simplex (EPX010-16019N-901) available. This assay enables the measurement of the neutralizing potential of antibodies towards the variant B.1.1.529 (o) in plasma and serum.

Figure depicting 4-plex panlel bead sets capture of the different neutralizing antibodies for SARS-CoV-2 wild type and variants

Figure 1. Schematic illustrating the principle of the Invitrogen ProcartaPlex 4-plex Neutralizing Antibody panel for SARS-CoV-2 variants.

SARS-CoV-2 ELISA serology assays

Ig ELISA for serum and plasma

The Human SARS-CoV-2 Spike (Trimer) Ig ELISA (enzyme-linked immunosorbent assay) kits are designed to measure the amount of Ig antibodies bound to SARS-CoV-2 Spike (Trimer). A trimerized Spike protein is pre-coated in the wells of the supplied microplate. Samples and controls, including a high control that can be used as a standard, are then added into these wells and bind to the immobilized (capture) Spike protein. The wells are washed, and anti-Ig conjugated to HRP are added and will bind to any captured antibodies. The wells are washed, and a substrate solution is added that reacts with the enzyme complex to produce measurable signal. The intensity of this signal is directly proportional to the concentration of antibody present in the original specimen.

Figure depicting the serology assay for SAR-CoV-2 using spike trimer protein for capture

Figure 6. Schematic illustrating the principle of the Invitrogen Ig Antibody ELISA for SARS-CoV-2.

Neutralizing antibody ELISA for serum and plasma

The SARS-CoV-2 Neutralizing Ab ELISA kit is designed to measure the neutralizing portion of anti-SARS-CoV-2 antibodies. A receptor binding domain (RBD) protein is pre-coated in the wells of the supplied microplate. Samples or the positive control are added into the wells. Neutralizing antibodies present in a sample that specifically bind to RBD will block any interaction with biotinylated ACE2 that is subsequently added. Signal from SA-HRP is indirectly proportional to the amount of specific neutralizing antibody present.

Figure 7. Schematic illustrating the principle of the Invitrogen Neutralizing Antibody ELISA for SARS-CoV-2.

Figure depicting the neutralizing antibody assay for SAR-CoV-2 using RBD protein for capture

Figure 11. Benchmarking to other supplier’s SARS-CoV-2 surrogate Virus Neutralization Test (sVNT) and conventional VNT. The Invitrogen ELISA showed strong correlation to other supplier´s ELISA and Plaque Reduction Neutralization Test (PRNT).

Cytokine storm detection for SARS-CoV-2 research

Artist rendition of a cytokine storm

Infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can result an increase in cytokine levels, also known as a cytokine storm and is considered to be one of the major causes of acute respiratory distress syndrome (ARDS) and multiple-organ failure. This cytokine storm, or cytokine release syndrome (CRS), is characterized by an imbalance in the cytokine network toward a pro-inflammatory response combined with an insufficient anti-inflammatory response, resulting in a loss of immune system homeostasis. Measure cytokine profiles related to cytokine storm syndrome (CSS) or cytokine release syndrome (CRS) triggered by SARS-CoV-2 infections.

ELISA kit for cytokine measurements
ProcartaPlex cytokine storm panels

Related products and resources
  1. Okba N, Müller MA, Li W, Wang C, GeurtsvanKessel CH, Corman VM, et al. Severe Acute Respiratory Syndrome Coronavirus 2−Specific Antibody Responses in Coronavirus Disease Patients.  Emerg Infect Dis. 2020;26(7):1478–1488.
  2. Jaimes JA, André NM, Chappie JS, Millet JK, Whittaker GR. Phylogenetic Analysis and Structural Modeling of SARS-CoV-2 Spike Protein Reveals an Evolutionary Distinct and Proteolytically Sensitive Activation Loop. 
    J Mol Biol. 2020;432(10):3309–3325.

Publications using the Human Coronavirus Ig Total 11-plex Panel

  1. Borena, W.; Kimpel, J.; Gierer, M.; Rössler, A.; Riepler, L.; Oehler, S.; von Laer, D.; Miholits, M. Characterization of Immune Responses to SARS-CoV-2 and Other Human Pathogenic Coronaviruses Using a Multiplex Bead-Based Immunoassay.  Vaccines 2021, 9, 611.
  2. Fraser DD, Cepinskas G, Slessarev M, Martin CM, Daley M, Patel MA, Miller MR, Patterson EK, O'Gorman DB, Gill SE, Oehler S, Miholits M, Webb B. Detection and Profiling of Human Coronavirus Immunoglobulins in Critically Ill Coronavirus Disease 2019 Patients. Crit Care Explor.  2021 Mar 12;3(3):e0369.