Some of the newer SARS-CoV-2 variants show resistance to the effect of neutralizing antibodies in laboratory experiments, according to a paper published in Nature Medicine. This finding may have implications for vaccine design and for the use of antibody therapies to treat COVID-19.
Neutralizing antibodies block the ability of viruses to enter host cells. They are produced by the body in response to both infection and vaccination and are important because they help to generate long-term immunity. However, whether antibodies to SARS-CoV-2 can also neutralize new variants of the virus remains unclear.
Michael Diamond, Pei-Yong Shi, Ali Ellebedy and colleagues assessed the ability of antibodies to neutralize some of the newer SARS-CoV-2 lineages, such as the United Kingdom variant (B.1.1.7), as well as genetically engineered chimeric viruses containing the spike proteins of South African (B.1.351) and Brazilian (B.1.1.248) variants, such as the Washington strain of SARS-CoV-2 (Wash SA-B.1.351).
The authors collected monoclonal antibodies and samples of serum (which contains neutralizing antibodies) from convalescent patients with COVID-19 and people who received the Pfizer–BioNTech vaccine, and then tested their neutralizing ability against a panel of naturally occurring SARS-CoV-2 variants and synthetic SARS-CoV-2 variants created in the laboratory. Most samples showed reduced inhibitory activity against viruses with the B.1.351 spike protein or other SARS-CoV-2 viruses that contained mutations at positions 484 and 501. This finding suggests that the current neutralizing antibodies may have less efficacy against the South African variants or other viruses with mutations at both 484 and 501.
The findings may have therapeutic implications, as immune plasma from people infected early during the pandemic might fail to protect patients infected with some of the newer strains. Adjustments may need to made to some of the existing therapeutic antibody cocktails, as well as vaccine sequences, but the authors caution that corroborative case studies in patients are needed to back up their findings.
The full paper is available at: https://www.nature.com/articles/s41591-021-01294-w
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