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Characteristics of replication and pathogenicity of SARS-CoV-2 Alpha and Delta isolates

Xiao-Li Feng1, Dandan Yu2, Mi Zhang3

  • 1Kunming National High-level Biosafety Research Center for Non-Human Primates, Center for Biosafety Mega-Science, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650107, China.

Virologica Sinica
|September 27, 2022
PubMed

Insights

The Alpha and Delta SARS-CoV-2 variants show more efficient replication in specific human cells and cause significant lung pathology in animal models. Continuous monitoring of these concerning variants remains crucial for public health.

Area of Science:

  • Virology
  • Pathogen Evolution
  • Public Health

Background:

  • The emergence of SARS-CoV-2 variants, including Alpha and Delta, poses a significant global health threat.
  • Constant monitoring of variant epidemics, pathogenicity, and immune escape is essential.

Purpose of the Study:

  • To characterize the replication and pathogenicity of Alpha and Delta SARS-CoV-2 variants isolated in Laos.
  • To identify amino acid mutations in the spike protein of these variants.

Main Methods:

  • Sequencing to determine amino acid mutations in the spike protein.
  • In vitro cell culture experiments using Calu-3, Caco-2, Huh-7, Vero E6, and HPA-3 cells.
  • In vivo animal studies using hACE2 transgenic mice and hamsters.

Main Results:

  • Alpha and Delta isolates demonstrated more efficient replication than the prototype SARS-CoV-2 in Calu-3 and Caco-2 cells.
  • Replication efficiency was not observed in Huh-7, Vero E6, and HPA-3 cells.
  • Alpha and Delta variants replicated in multiple organs and induced moderate to severe lung pathology in animal models.

Conclusions:

  • The spike protein mutations of isolated Alpha and Delta variants were characterized.
  • The study evaluated the replication and pathogenicity of these SARS-CoV-2 variants in cellular and animal models.
Keywords:
AlphaDeltaHamsterSARS-CoV-2Variants of concern (VOC)hACE2 transgenic mice

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