Viral Antigens
Viral antigens in this range are recombinant structural and non-structural proteins from major human viral pathogens, including SARS-CoV-2, SARS, MERS, Influenza A, Hepatitis B, Hepatitis C, HIV and Cytomegalovirus. Proteins are supplied unconjugated, produced across CHO, HEK293, insect cell and P.pastoris expression systems, with several SARS-CoV-2 targets available as variant-specific B.1.1.7 and B.1.1.529 (Omicron) constructs.
Browse Viral AntigensTwo Constructs at the Centre of SARS-CoV-2 Research
The Spike S Trimer and the Omicron RBD were chosen because they carry the most extensively characterised functional and structural data in the range: an ACE2 binding curve for the trimer, and SEC-HPLC purity data alongside a well documented mutation profile for the Omicron RBD.
SARS-CoV-2 Spike Protein S Trimer (STJP000276)
The SARS-CoV-2 spike receptor-binding domain engages ACE2 through a binding interface of around 850 Ų, with 18 residues on the RBD forming direct contacts with the receptor.1 This HEK293-expressed trimeric spike protein was coated at 0.1 µg per well and bound to human ACE2-Fc with a linear range of 23 ng/ml, confirming trimer-level receptor engagement.
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COV2 Spike Protein RBD B.1.1.529 (Omicron) (His-Tag) (STJP000263)
The Omicron receptor-binding domain carries 15 mutations relative to the original sequence, several of which drive escape from RBD-targeted neutralizing antibodies raised against earlier variants.2 This HEK293-expressed construct reports purity greater than 95 percent by SEC-HPLC, supporting its use as a defined reference antigen for variant comparison work.
View product →Viral Antigens From the Original SARS-CoV-2 Sequence
Structural proteins from the original 2019-nCoV sequence, covering the two proteins most used in serology and receptor-binding research. The spike protein mediates ACE2 receptor engagement and cell entry, and is supplied here as the full S trimer and as the isolated S1 subunit, which contains the receptor-binding domain. The nucleocapsid protein packages the viral RNA genome and is a principal target of anti-nucleocapsid serology assays. The B.1.1.7 spike S1 construct extends this set with an early variant of concern for comparison against the original sequence.
Viral Antigens From the B.1.1.529 (Omicron) Variant
Parallel spike, receptor-binding domain and nucleocapsid constructs from the B.1.1.529 (Omicron) variant, which carries more than 30 mutations in the spike protein, 15 of them in the receptor-binding domain.2 Mutations including K417N and N501Y have well characterised roles in immune escape and altered receptor affinity.2 These HEK293-expressed constructs support side-by-side comparison against the original sequence in ELISA, SPR and neutralization assay formats.
Viral Antigens From SARS-CoV and MERS-CoV
Spike proteins from the two coronaviruses most closely related to SARS-CoV-2 by receptor tropism and disease history. SARS-CoV, like SARS-CoV-2, uses ACE2 as its cell receptor, and its spike protein is supplied here as the full S protein and as an Fc-tagged S1 subunit. MERS-CoV instead uses DPP4 as its receptor, and is represented by its spike S1 subunit and receptor-binding domain. Comparing spike constructs across SARS-CoV-2, SARS-CoV and MERS-CoV supports research into shared and divergent features of coronavirus receptor engagement.
Viral Antigens From Influenza, Hepatitis, HIV and CMV
Structural and non-structural proteins from viral pathogens outside the coronavirus family. Influenza A hemagglutinin from the H5N1 subtype mediates receptor binding and membrane fusion during viral entry, hepatitis B surface antigen is the principal serology target for HBV infection, hepatitis C core protein forms the viral nucleocapsid, and HIV-1 gp120 is the envelope glycoprotein responsible for CD4 receptor binding. These targets support serology development, receptor binding studies and structural work across viral families outside SARS-CoV-2.
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Browse the full range of recombinant viral antigens, or contact us if a specific target or variant construct is not listed.
Browse Viral Antigens1. Lan J, Ge J, Yu J, et al. Structure of the SARS-CoV-2 spike receptor-binding domain bound to the ACE2 receptor. Nature. 2020;581(7807):215-220.
2. Cao Y, Wang J, Jian F, et al. Omicron escapes the majority of existing SARS-CoV-2 neutralizing antibodies. Nature. 2022;602(7898):657-663.