Recently, ACROBiosystems announced its latest antigen products targeting an emergent Omicron mutation, BA.2.75.
Image Credit: ACROBiosystems
Since May, there has been an exponential spread of BA.2.75 throughout India. Shortly after this new mutation was discovered, new related cases were identified in a number of other countries around the world, including Australia, Germany, the UK and the US.
Unofficially nicknamed “Centaurus,” the World Health Organization (WHO has classified BA.2.75 as a Variant of Interest (VOIs) instead of a Variant of Concern (VOCs). Although it remains unclear what level of threat of this emerging Omicron mutation presents, medical experts around the world are concerned about its presence.
Dr. Maria Van Kerkhove, technical lead on COVID-19 at the WHO, suggested that there are an insufficient number of samples for a comprehensive analysis of BA.2.75. Currently, only 200 sequences have been taken from 14 countries: a significant limiting factor when it comes to better understanding this mutation.
Due to the fact a large portion of the population is immunized against COVID-19, newer variants are demonstrating a high level of immune evasion, which is also becoming the norm. As such, infection rates by novel COVID variants are expected to rise in spite of a significant number of people being vaccinated.
Such concerns were similarly confirmed in a recent study by Yamasoba, et al. Out of 10 therapeutic monoclonal antibodies tested against BA.2.75 and other novel variants, the majority of therapies approved failed to neutralize the COVID variants, particularly BA.2.75.2
Contrary to the other Omicron subvariants, Centaurus (BA.2.75) has shown to display additional mutations beyond the same high-level variant structure as Omicron BA.2. There are 17 more nucleotide mutations of BA.2.75 in contrast to BA.2 as confirmed by recent sequence analysis of both variants.
Numerous key mutations, G446S and Q493R on the Spike protein, have considerable antigen-converting effects. Based on studies previously conducted, the G446S mutation is one of the most efficient immune escape sites, while the Q493R mutation may consolidate the affinity between the virus and the ACE2 receptor.
Image Credit: ACROBiosystems
The emergence of novel COVID variants with greater rates of infection places a spotlight on the long-term vaccine strategy and raises many questions.
An increasing number of experts have begun to adopt the idea of utilizing a ‘booster shot’ rather than continuing to develop new vaccine programs to combat the new variants. Recently, Moderna announced that two potential boosters targeting the Omicron subvariants are expected to be released this fall.
Neutralization assays were performed using pseudoviruses harboring the SARS-CoV-2 Spike proteins of BA.2, BA.4/5, and BA.2.75. YAMASOBA.2. Image Credit: ACROBiosystems
In today’s COVID-19 landscape, it remains that the dominant coronavirus strain in a number of countries is the extremely contagious BA.5 Omicron subvariant. As reported by the Global Initiative on Sharing All Influenza Data (GISAID), the data surrounding BA.5 accounted for 52% of the sequence library.
Moreover, the study highlights that the R0 value, a nominal value that indicates infectiousness, is 18.6. This is around six times more infectious than the wild-type, making it the most transmissible subvariant of the SARS-CoV-2 virus.
To support the development of vaccines and respond to the rapid demands of the market, i.e., targeting newer and emerging COVID variants, ACROBiosystems’ has released a new range of BA.2.75 antigen-related products.
With the changing nature of COVID-19, ACROBiosystems continuously strives to supply the evolving key antigens for vaccine research, including the Spike timer, S RBD, and Nucleocapsid protein.
- Availability of Spike trimer, S RBD, S1, S2, NTD and N protein in biotinylated and unconjugated versions
- Encompasses almost all new Omicron subvariants: BA.4/5, BA.2.74/75/76, BA.2.38, etc.
- High bioactivity is validated by stringent quality control processes, which are appropriate for ELISA/SPR/BLI and other experiments
- Purity exceeds 95% verified by SDS-PAGE and over 90% determined by MALS
The purity of SARS-CoV-2 Spike Trimer, His Tag (BA.2.75/Omicron) (Cat. No. SPN-C522f) is more than 90% verified by SEC-MALS. The molecular weight of this protein is around 496-548 kDa. Image Credit: ACROBiosystems
Measured by its binding ability in a functional ELISA. Immobilized SARS-CoV-2 Spike Trimer, His Tag (BA.2.75/Omicron) (Cat. No. SPN-C522f) at 1 μg/mL (100 μL/well) can bind Human ACE2, Fc Tag (Cat. No. AC2-H5257) with a linear range of 0.2-16 ng/mL (QC tested). Image Credit: ACROBiosystems
SARS-CoV-2 Spike Trimer, His Tag (BA.2.75/Omicron) (Cat. No. SPN-C522f) at 1 μg/mL (100 μL/well) can bind Anti-SARS-CoV-2 Spike RBD Broadly Neutralizing Antibody, Human IgG1 (Cat. No. SPD-M265) with a linear range of 0.1-2 ng/mL (Routinely tested). Image Credit: ACROBiosystems
- Topol, E., 2022. BA.5, Chapter 2. [online] Erictopol.substack.com. Available at: https://erictopol.substack.com/p/ba5-chapter-2.
- Yamasoba D, Sato K, et al, 2022. Neutralization sensitivity of Omicron BA.2.75 to therapeutic monoclonal antibodies. The Lancet Infectious Diseases.
ACROBiosystems is a leading manufacturer of recombinant proteins and other critical reagents to support the development of target therapeutics. The company employs an application oriented development strategy, with a particular focus on product design, quality control and solution based support. Our products and services enable anyone in the field of drug development to have a more intuitive and streamlined process.
To respond to coronavirus pandemic, ACROBiosystems has developed SARS-CoV-2 antigens specifically designed and optimized for serological test kits, including Spike-derived antigen S1, RBD and Nucleocapsid protein. Proteins have been supplied to diagnostic companies in large quantity.
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