Arushi Bidhuri
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Written By: Arushi Bidhuri | Updated : June 26, 2021 6:15 PM IST
Changes In Spike Protein In Covid Variants Can Render Current Vaccines Ineffective
As SARS-CoV-2, the virus that causes Covid-19, develops, it is more likely to mutate, resulting in novel variations and alterations to the spike protein, which might render current vaccinations targeting the protein useless. The spike protein of the Alpha, originally identified in the UK, and Beta, first identified in South Africa variations has been discovered to exhibit novel characteristics by researchers from Boston Children's Hospital. The modifications to the 'spike' protein explain why Alpha spreads so quickly and how the Beta form evades immune responses, indicating that a booster shot with a revised vaccination is required.
"The mutations make antibodies stimulated by the current vaccine less effective," said Bing Chen, in the division of Molecular Medicine at Boston Children's. "The Beta variant is somewhat resistant to the current vaccines, and we think a booster with the new genetic sequence can be beneficial for protecting against this variant," Chen added.
All existing vaccines target spike proteins, which are found on the surface of SARS CoV-2 and allow the virus to adhere to and enter human cells. Cryo-electron microscopy (cryo-EM) was used to compare the spike protein from the original virus with that of the Alpha and Beta versions in a recent study published in Science.
Mutations in the Beta variation (also known as B1351) affect the shape of the spike surface at specific places, according to the structural results. As a result, existing vaccine-induced neutralising antibodies are less able to attach to the Beta virus, allowing it to elude the immune system even when patients are vaccinated.
The study also discovered that mutations in the Beta form reduce the spike's ability to attach to ACE2, implying that it is less transmissible than the Alpha variant. In the case of the Alpha version (B117), the research reveals that a single amino acid alteration in the spike helps the virus attach better to ACE2 receptors, making it more infectious. Antibodies generated by current vaccinations, however, appear to be able to neutralise this version.
(with inputs from IANS)
