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Basic Characteristics of Mutations
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Mutation Site
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L50F |
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Mutation Site Sentence
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Among them, we selected L50F/E166V and L50F/E166A/L167F in the 3CLpro because these combinations of substitutions are unlikely to affect virus fitness. |
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Mutation Level
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Amino acid level |
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Mutation Type
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Nonsynonymous substitution |
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Gene/Protein/Region
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3CLpro |
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Standardized Encoding Gene
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ORF1a
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Genotype/Subtype
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B.1.617.2 |
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Viral Reference
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OR116091
|
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Functional Impact and Mechanisms
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Disease
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Cell line
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Immune
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- |
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Target Gene
|
-
|
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Clinical and Epidemiological Correlations
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Clinical Information
|
- |
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Treatment
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nirmatrelvir |
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Location
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- |
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Literature Information
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PMID
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37402789
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Title
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In vitro and in vivo characterization of SARS-CoV-2 strains resistant to nirmatrelvir
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Author
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Kiso M,Furusawa Y,Uraki R,Imai M,Yamayoshi S,Kawaoka Y
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Journal
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Nature communications
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Journal Info
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2023 Jul 4;14(1):3952
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Abstract
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Nirmatrelvir, an oral antiviral agent that targets a SARS-CoV-2 main protease (3CLpro), is clinically useful against infection with SARS-CoV-2 including its omicron variants. Since most omicron subvariants have reduced sensitivity to many monoclonal antibody therapies, potential SARS-CoV-2 resistance to nirmatrelvir is a major public health concern. Several amino acid substitutions have been identified as being responsible for reduced susceptibility to nirmatrelvir. Among them, we selected L50F/E166V and L50F/E166A/L167F in the 3CLpro because these combinations of substitutions are unlikely to affect virus fitness. We prepared and characterized delta variants possessing Nsp5-L50F/E166V and Nsp5-L50F/E166A/L167F. Both mutant viruses showed decreased susceptibility to nirmatrelvir and their growth in VeroE6/TMPRSS2 cells was delayed. Both mutant viruses showed attenuated phenotypes in a male hamster infection model, maintained airborne transmissibility, and were outcompeted by wild-type virus in co-infection experiments in the absence of nirmatrelvir, but less so in the presence of the drug. These results suggest that viruses possessing Nsp5-L50F/E166V and Nsp5-L50F/E166A/L167F do not become dominant in nature. However, it is important to closely monitor the emergence of nirmatrelvir-resistant SARS-CoV-2 variants because resistant viruses with additional compensatory mutations could emerge, outcompete the wild-type virus, and become dominant.
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Sequence Data
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OR116092;OR116093
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