Tools to Accelerate COVID-19 Vaccine Development

Detect, Screen and Monitor Immune Responses

With the persistent and ongoing threat of the coronavirus pandemic, infection prevention and establishment of herd immunity is a top priority, necessitating the continued development of COVID-19 vaccines that are inexpensive and easy to distribute across the globe. Developing successful and effective vaccines requires evaluating host immune responses to the virus in large study groups. In support of these efforts, RayBiotech provides a versatile range of reagents and kits to address the need for detection of SARS-CoV-2 antigens, monitoring immunoreactivity, and titering viral neutralizing antibodies in patient specimens.


To address the need for viral protein detection in patient samples, we provide high quality immunoreagents for ELISA development as well as finished kits.

Sandwich ELISA Kits

  • Ready-to-use kit with pre-coated strip plates
  • Compatible with serum, plasma, nasal swabs & saliva
  • 6 hour work flow
  • Alternative to qPCR

COVID-19 Nucleocapsid Protein ELISA Kit

COVID-19 Spike Protein (S1RBD) ELISA Kit

Patient swab data
Patient swabs were tested for presence of SARS-CoV-2 N protein by RayBio COVID-19 N Protein ELISA (4-fold dilution). Positive = tested positive for COVID-19 (RT-PCR).

Sandwich ELISA Reagents

  • Matched antibody pairs and standards
  • SARS-CoV-2 Spike and Nucleocapsid proteins
  • Pre-validated, ready for development of any sandwich immunoassay
  • Biotin labeling available upon request

Binding Assay and Pseudovirus

A critical molecular event in COVID-19 infection is the interaction between the viral spike RBD (S1 RBD) and the receptor on the human epithelial cell surface, which mediates cellular invasion by the virus. Thus, neutralizing antibodies (nAbs) which can block this interaction are an important defense against future SARS-CoV-2 infections.

The detection of nAbs is a key indicator that protective immunity has been established. In vaccine efficacy trials, efficient methods of nAb titering are needed. We have developed a series of in vitro binding assays which allow not only the rapid screening of patient sera for nAbs but can also validate inhibitors of SARS-CoV-2 infectivity.

Binding Assays

The S1 RBD may bind to several different host cell surface receptors, including ACE2 and neuropilin-1. The RayBio COVID-19 Spike-ACE2 and Spike-NRP1 Binding Assay Kits are plate-based colorimetric assays for measuring neutralizing activity of antibodies, sera, or other inhibitors.

Inhibition of Spike-ACE2 by anti-viral compounds

Small molecule neutralizing activity using RayBio binding assay
Four small molecules tested for neutralizing activity with RayBio COVID-19 Spike-ACE2 Binding Assay (COV-SACE2).

Inhibition of Spike-ACE2 by anti-Spike antibodies

Antibody neutralizing activity using RayBio binding assay
Four antibodies tested for neutralizing activity with RayBio COVID-19 Spike-ACE2 Binding Assay (COV-SACE2). nAb 1 = 130-10807; nAb 2 = 130-10844; nAb 3 = 130-10845; negative control = 130-10813.

COVID-19 Pseudovirus Service

RayBiotech's COVID-19 pseudovirus service enables the study of the SARS-CoV-2 virus in cell culture. This service is ideal for:

  • Screening patient serum for neutralizing antibodies
  • Validating inhibitors of the Spike-ACE2 interaction
  • COVID-19 vaccine development

Monitor Antibody Responses to COVID-19

RayBiotech provides tools to help you monitor COVID-19 vaccine effectiveness, including validated antibodies, proteins, and ready-to-use kits for detection of immunoreactivity with SARS-CoV-2 antigens.

Indirect ELISA Kits

Antibody screening has an important role in determining immunity to and prevalence of COVID-19, as well as identifying who has been infected and evaluating potential blood-based therapeutics. Indirect ELISA (iELISA) is a reliable, powerful technique for determining total antibody concentrations in a sample.

  • Ready-to-use kit with pre-coated plates
  • Results in <3 hours
  • Kits available for IgG, IgM and IgA
  • Validated with serum, plasma, saliva, or dried blood (varies by kit)
IgG indirect ELISA detection data
RayBio COVID-19 Human IgG iELISA Kit (IEQ-CoVSN-IgG) used to detect spike RBD IgG in the sera of COVID-19-positive patients (PCR diagnosis) and uninfected individuals.

Indirect ELISA Reagents

Control Antibodies

RayBiotech's range of anti-SARS-CoV-2 antibodies includes monoclones that are validated as iELISA positive controls, allowing for rapid development and calibration of your diagnostic immunoassays. The product range also includes clones with SARS-CoV-2 neutralizing activity.

Coating Proteins

RayBiotech has an extensive catalog of recombinant SARS-CoV-2 antigens, including nucleocapsid, spike domains, and membrane protein. Choosing one or a mixture of viral components allows you to tailor an antibody screening assay to your needs.

Patient Samples

Patient samples enable the measurement of cellular and humoral immune responses to COVID-19 infection or COVID-19 vaccination. RayBiotech offers serum, plasma, dried blood spots, and peripheral blood mononuclear cells (PBMCs) samples from a variety of patients to accelerate COVID-19 vaccine development.

"Normal" Non-COVID-19 Samples

Samples collected before the outbreak of COVID-19, thus these samples were taken from patients who were not infected with COVID-19.

  • Serum / Plasma

COVID-19 Patient Samples

Samples collected from patients confirmed to have COVID-19 via a SARS-CoV-2 nucleic acid-, antibody-, or antigen-based test.

  • Sample sets available (10 normal + 20 COVID-19 patient samples)
  • Serum / Plasma / Dried blood spots / PBMCs
  • Whole blood & granulocytes upon request

COVID-19 Vaccinated Samples

Samples collected from patients who received an FDA-approved vaccine.

  • Single collections obtained after completion of the vaccination schedule
  • Time-series collections obtained before, during, and after the vaccination schedule
  • Serum / Plasma / Dried blood spots / PBMCs
  • Whole blood & granulocytes upon request
Measurement of COVID-19 plasma with an in vitro binding assay.
Measurement of COVID-19 plasma with an in vitro binding assay. Patient plasma was diluted at 1:20 and 1:125 and analyzed with the RayBio® Spike-ACE2 Binding Assay Kit (cat no. CoV-ACE2S2). Error bars represent triplicate analyses.
Neutralization analysis by SARS-CoV-2-S-driven entry.
Neutralization analysis by SARS-CoV-2-S-driven entry. A pseudovirus expressing the SARS-CoV-2 Spike protein on the surface was incubated with A549 cells expressing the ACE2 receptor ("ACE2 cell") or NIH3T3 cells not expressing the ACE2 receptor ("Non-ACE2 cell"). Serum containing a neutralizing antibody was added at 400-, 200-, or 100-fold dilutions. Luminescence reflecting viral entry was measured, and the average luminescence across three independent experiments relative to the “no serum” sample data is shown. Error bars indicate standard deviations. Data obtained with RayBiotech's COVID-19 Pseudovirus Service.