Kappa Variant - Luciferase-tagged RBD protein

Recombinant RBD fusion protein (B.1.617.1 variant - Indian origin) for ELISA & LIPS

RBD-LuciaV7 (B.1.617.1) (~52 kDa) is a soluble fusion protein composed of the Spike Receptor Binding Domain (RBD) from the SARS-CoV-2 Kappa variant (B.1.617.1) fused to a C‑terminal Lucia luciferase tag. RBD-LuciaV7 (B.1.617.1) has been specifically designed to assess the binding affinity of anti-Spike antibodies using either ELISA or LIPS (luciferase immunoprecipitation systems) assays [1-3].

More details

SARS-CoV-2 Spike RBD

RBD-LuciaV7 (B.1.617.1) contains the Spike RBD domain, including the receptor-binding motif (RBM) from the SARS-CoV-2 Kappa variant, first reported in India in October 2020 [4]. This variant is classified as a member of Clade 21B/ B.1.617.1 lineage (Nextstrain/Pango lineage classification). It is characterized by the presence of two key mutations within the Spike RBD coding region, which are of concern [4].

• L452R, E484Q

Learn more about the emerging SARS-CoV-2 variants around the world

Applications

Luciferase-tagged RBD proteins are ideal for studying the binding of anti-spike monoclonal antibodies (mAbs) by solid-phase ELISA and/or solution‑phase LIPS assays, as well as anti‑spike polyclonal antibodies in the sera of recovered COVID‑19 patients and/or vaccinees by LIPS [1-3].

• ELISA: the Lucia luciferase tag provides a larger dynamic range than the commonly used HRP detection.
• LIPS: for the detection of antibodies, against both linear and conformational epitopes.

Importantly, using InvivoGen's expanding collection of Spike variant RBD-Lucia proteins, it can be seen that the SARS-CoV-2 variants display varying binding affinities to the different clinically relevant anti-Spike mAbs (see right). RBD‑LuciaV7 (B.1.617.1) has been generated by recombinant DNA technology, produced in CHO cells, and purified by IMAC (Immobilized Metal Affinity Chromatography) using a C‑terminal histidine tag. Protein size and purity (>90%) have been validated by SDS‑PAGE and the absence of endotoxin contamination has been confirmed using cellular assays.

References:

1. Burbelo, P.D. et al. 2010. Antibody-profiling technologies for studying humoral responses to infectious agents. Expert Rev Vaccines 9, 567-578.
2. Haljasmagi, L. et al. 2020. LIPS method for the detection of SARS-CoV-2 antibodies to spike and nucleocapsid proteins. Eur J Immunol 50, 1234-1236.
3. Liang, Y. et al. 2021. A luciferase immunosorbent assay for quantitative detection of IgG antibodies against SARS-CoV-2 nucleoprotein. J Virol Methods 292, 114141.
4. Liu, C. et al. 2021. Reduced neutralization of SARS-CoV-2 B.1.617 by vaccine and convalescent serum. Cell, doi:10.1016/j.cell.2021.06.020.