► Selection of recombinant antigens

► Eukaryotic expression system (insect cells)

► ELISA, bead assay and LF approved

► ISO 13485 certified manufacturing conditions

SERION antigens

Coronavirus - SARS-CoV-2

Since mid-December 2019, the pathogen Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is on the rise. The worldwide spread of the Coronavirus Disease 19 (COVID-19) was declared a pandemic by the WHO on March 11, 2020. Typical clinical symptoms of affected patients are fever, dry cough, shortness of breath, headache and pneumonia. Severe disease progressions lead to respiratory arrest due to alveolar damage, septic shock and/or multiple organ dysfunction or failure and can be fatal.

SARS-CoV-2 Antigens

The enveloped, single-stranded RNA virus SARS-CoV-2 consists of 4 structural proteins and 16 non-structural proteins. The 4 structural proteins are spike, envelope, nucleocapsid and membrane. Spike protein consists of two domains: the S1 domain, which contains the receptor binding domain (RBD) for host cell interaction, and the S2 domain containing the transmembrane and endodomain. It is presented on the viral surface in a trimeric structure.

Neutralizing antibodies during host immune responses are predominantly directed against the spike protein, which is supposedly suitable for very specific test settings as it is less conserved within the family of Coronaviridae than the other immunogenic antigens[1,2]. However, recent studies have shown that antibodies directed against nucleocapsid protein are detectable earlier in mild infections than antibodies against spike protein[3]. Especially as acute marker, it can be beneficial to use nucleocapsid for the detection of IgA and IgM antibodies in order to enable early sensitive detection. In the further course of the immune response the nucleocapsid antibody level decreases, while antibodies against spike protein are detectable for a longer time.

Click here for more information about COVID-19 diagnostics.

Available SERION antigens

The new recombinant SERION Immunologics SARS-CoV-2 antigens are designed for the detection of IgA, IgG and IgM antibodies. Their superior performance has been shown in ELISA, bead based immunoassays such as CLIA, and lateral flow (LF) applications. The recombinant expression within an ISO 13485 certified production environment in bioreactor systems guarantees highest lot-to-lot consistency. Choose your antigen combination for the development of highly specific and sensitive antibody detection assays!

Please let us know if you are interested in 0.25 mg test samples.


  • SARS-CoV-2 Nucleoprotein, BA400R04

Recombinant nucleocapsid protein expressed in insect cells.

Molecular weight: 47 kDa.


  • SARS-CoV-2 Spike Ectodomain (S1-S2), BA400R03

Recombinant spike glycoproteins comprised of multiple S1 and S2 domains expressed in insect cells.

Molecular weight: 135 kDa.



SARS-CoV-2 Nucleoprotein
SERION antigens
SARS-CoV-2 Spike Ectodomain (S1-S2)
SERION antigens


[1] Suresh et al., "Molecular Targets for Diagnostics and Therapeutics of Severe Acute Respiratory Syndrome (SARS-CoV)", J Pharm Pharm Sci. Author manuscript; available in PMC 2009 May7

[2] Meyer et al., "Serological Assays for Emerging Coronaviruses: Challanges and Pitfalls", Virus Research 194 (December 2014)

[3] Guo L. et al., "Profiling Early Humoral Response to Diagnose Novel Coronavirus Disease (COVID-19)", Clinical Infectious Diseases, March 21st 2020