Optimer™ reagents bind to RBD of UK COVID-19 variant
We demonstrate that Optimer binders show equivalent binding to both the WT and new COVID-19 variant for continued reliable results in research, diagnostics and therapeutics.
Newly emerging, fast-spreading variants of the coronavirus are causing another headache in tackling the pandemic. From the UK and Brazil to South Africa, the US and now Germany, new variants of Covid-19 have been causing concern wherever they emerge.
At the end of 2020, following rapid approval of the COVID-19 vaccines from Pfizer/BioNtech and Moderna, a new COVID-19 variant was reported in the UK. This new ‘UK variant’, B.1.1.7, is more transmissible than previous strains of the virus, resulting in rises in cases, hospital admissions and deaths and prompting a new lockdown across the UK at the beginning of January.
COVID-19 variant: researching, testing and treating
Mutations continuously arise during viral replication. Even within the same patient, different mutations of the same virus can be present. The COVID-19 virus has been mutating ever since it emerged, but most of these mutations haven’t caused any significant changes that would raise alarm. We are only usually interested in viral mutations if it alters their transmissibility or virulence.
There has been concern that these new COVID-19 variants may prevent the efficacy of the developed vaccines and tests and put us back to square one in the race to beat COVID-19. Suppose these new mutations affect the binding of affinity reagents by preventing their binding or changing the affinity for the viral target. In that case, this could affect the interpretation of assays based on these reagents, alter the sensitivity of diagnostic assays or reduce the efficacy of therapeutics.
Equivalent Optimer binding to COVID-19 variant and WT
At the start of the pandemic, Aptamer Group deployed our rapid selection processes to identify Optimer binders specific to SARS-CoV-2. In just 17 days, we developed Optimers with high specificity and high affinity for the S1 and S2 subunits and to the recognition binding domain (RBD) of the COVID-19 Spike protein.
For more information about our COVID-19 Optimers, download the application note.
With the development of the new COVID-19 variant, we analysed our COVID-19 Optimer reagents’ binding to both the earlier strain and the new COVID-19 variant via biolayer interferometry.
Using the RBD protein of the B.1.1.7 COVID-19 variant and the WT protein, we assessed the binding of our COVID-19 RBD-specific Optimers using the Octet Red384 platform.
Biosensor analysis COVID-19 variant and WT with RBD-specific Optimers equivalent binding to both forms of the viral protein. BLI streptavidin probes were coated with 20 nM biotinylated Optimer, washed and the interaction measured in 80 μl of the target protein in buffer over the concentration range shown.
Equivalent binding was noted for the RBD-specific Optimer to both the COVID-19 variant and the earlier strain of the viral protein with target affinity for each of the targets highly comparable.
This shows that the new COVID-19 variant would not affect any data generated with this Optimer and that it could be used in the same way for both the earlier and newly emerging strains of COVID-19 to offer the same level of assay sensitivity and reliability for your work.
To find out how our alternative S1, S1 and NC Optimers interact with the new COVID-19 variant please get in touch for more information.
Will the reliability of COVID-19 tests be affected?
The most widely used test formats for COVID-19 diagnostics are RT-PCR and increasingly lateral flow tests (LFTs). While PCR offers increased accuracy over the available COVID-19 LFTs, LFTs’ speed and convenience mean their use is central to reducing the spread of the disease in our populations.
The primers and probes used within RT-PCR assays are designed to target conserved elements within the viral genome, so mutations such as the new COVID-19 variants being seen are unlikely to affect the test’s sensitivity. However, LFTs do not work in the same way and are based on antibodies to COVID-19 proteins, which may change in new COVID-19 variants. Consequently, new mutations and variants of COVID-19 may impact the efficacy of these tests and we must consider the specific reagents used in each test when considering the results.
We will continue to monitor the performance of our Optimer reagents to new COVID-19 variants as they emerge, and we will continue to update you with any further results so that you can be sure that your work with these reagents is always accurate.