Anti-SARS-CoV-2 Antibodies Bind to the Coronavirus Omicron Variant

In November 2021, people around the world started to realize that a new, fast-spreading coronavirus variant posed a new threat, opening the next chilling chapter in the COVID-19 pandemic. The Omicron variant (B.1.1.529) – as this new strain was designated – was shown to have an unprecedented number of mutations in the spike protein compared to previous variants, and it seems to be spreading significantly faster than its predecessors. Considerable genetic differences pose a threat to the effectiveness of the current vaccines and antibodies targeting the virus, and thus Absolute Antibody performed in-detail testing of our anti-SARS-CoV-2 spike protein clones with the mutant Omicron protein.

We are glad to announce that many of our coronavirus antibodies are still potent binders of the Omicron variant (CR3022, CV1, EY6A) and can be used effectively as reagents for research and diagnostics at this stage of the pandemic. Simultaneously, several clones failed to detect the Omicron variant (CV30, Sb#15), which makes them strong candidates for the differentiating detection of certain coronavirus mutants. ELISA data showing the binding curves for each clone can be seen below, along with a summary of how the clones have performed against key coronavirus variants to date.

Antibodies that still retained affinity for the Omicron variant bound epitopes on the receptor binding domains that do not completely block ACE2 binding, while antibodies competing with ACE2 binding lost the ability to bind. This is in line with the accumulation of mutations in the ACE2 binding site of the Omicron RBD (Mannar et al, 2021).

All anti-coronavirus clones tested against the Omicron variant are available in our catalog in a wide variety of engineered formats, designed to open up new experimental possibilities for in vitro and in vivo use. Some of the formats include:

• Human IgG1, IgG2, IgG3, IgG4, IgA, IgM and IgE for use in neutralization assays and as serological controls
• Rabbit, mouse, cat and ferret formats for detection applications, co-labeling studies and animal model research
• Human and mouse Fab and Fab2 formats with His-tags, for applications where antibody fragments are desirable and for site-specific functionalization
• Human IgG1 and mouse IgG2b Fc Silent™ formats, which are aimed at discerning Fc-dependent and Fc-independent effector functions and facilitating research into the role of antibody-dependent enhancement (ADE)

Learn more about each antibody format here or contact us if you are looking for these clones in a different format. You can also find our full collection of anti-coronavirus antibodies on our website here.

Figure 1. ELISA using anti-SARS-CoV-2 spike antibodies with the Omicron spike variant (B.1.1.529). ELISA plate was coated with the Omicron SARS-CoV-2 spike protein (REC32008; The Native Antigen Company) at 2.5 µg/ml. The antibodies CR3022 (Ab01680), CV1 (Ab02018), CV30 (Ab02019), Sb#15 (Ab02013), EY6A (Ab02057) and an isotype control (Ab00102) were conjugated to HRP and titrated on a three-fold serial dilution starting at 3000 ng/ml.

Table 1. Chosen anti-coronavirus antibodies and their binding to the major SARS-CoV-2 spike variants assessed by ELISA. ✓ = binding