Scientists from the USA have found a mutation that allows the delta variant of SARS-CoV-2 to avoid antibodies 
Researchers from the USA have found an explanation for why the delta and kappa variants of the coronavirus are able to evade neutralizing antibodies. The article of scientists was published in the journal Science.
Experts from the University of Washington collected plasma samples from 37 people aged 22 to 66 years, vaccinated with drugs Moderna, Pfizer or Johnson & Johnson. It turned out that with the delta, kappa and delta plus variants of SARS-CoV-2, the neutralizing ability of antibodies produced during vaccination decreased in patients. The largest decrease was noted for the delta plus variant. In half of those who received the Johnson & Johnson vaccine, antibodies lost the ability to neutralize one of the variants.
Using cryoelectron microscopy, researchers studied mutations in S-proteins – the main tools that allow infecting a cell – of three variants of coronavirus. It turned out that the delta variant underwent a “stunning rearrangement” of the N-terminal domain of the protein, which allowed it to become more plastic when evading antibodies. At the same time, the ability to bind to the ACE2 receptor in the delta and kappa variants remained comparable to the Wuhan variant, and even decreased in the delta plus variant.
Scientists analyzed the interaction of coronavirus variants with 11 antibodies. One of the latter, the S2X303, has been shown to be capable of cross-reacting with several options at once. Experts analyzed how it neutralizes coronavirus and found that it binds to the N-terminal domain at an unusual angle – almost 90 degrees different from other antibodies. The researchers hope their findings will help develop new vaccines against COVID-19.