BREAKING🎄 The 6th preprint from G2P-Japan - #Omicron is less infectious and pathogenic than #Delta and even an early pandemic SARS-CoV-2 in infected hamster model. 1/5
How come?
We have recently reported that Delta spike is efficiently cleaved into two subunits, and therefore, Delta is highly fusogenic and highly pathogenic @Nature . 2/5 nature.com/articles/s4158…
In sharp contrast, Omicron is less fusogenic (left panel) and its spike is faintly cleaved (right panel). Our data suggest that the efficacy of spike protein cleavage, fusogenicity and pathogenicity are well correlated each other. 3/5
A new preprint "An emerging SARS-CoV-2 mutant (='the California variant', B.1.427/429) evading cellular immunity and increasing viral infectivity", from The G2P-Japan consortium, organized by my lab, is out at @biorxivpreprint. Please RT 1/7 biorxiv.org/content/10.110…
During the current SARS-CoV-2 pandemic that is devastating the modern societies worldwide, many variants that naturally acquire multiple mutations have emerged. Emerging mutations can affect viral properties such as infectivity and immune resistance. 2/7
The sensitivity of naturally occurring SARS-CoV-2 variants to 'humoral immunity (=neutralizing antibodies)' has recently been investigated. However, the impact of viral mutations to human leukocyte antigen (HLA)-restricted 'cellular immunity' remains unaddressed. 3/7
Please notice: we revealed that SARS-CoV-2 ORF3b, one of the most different genes compared to SARS-CoV, strongly hampers human type I IFN activation. Its inhibitory activity is stronger than the SARS-CoV ortholog and influenza A virus NS1. #COVID19 1/7 biorxiv.org/content/10.110…
Our findings may explain the poor IFN responses in #COVID19 patients and SARS-CoV-2-infected cells compared to SARS-CoV- and influenza A virus-infected cells, recently reported by @DBM003@virusninja and so on, are attributed to the remarkable ability of SARS-CoV-2 ORF3b. 2/7
Additionally, we revealed that the ORF3b genes of SARS-CoV-2-related viruses in bats and pangolins are very similar to that of SARS-CoV-2 and possess the activity to inhibit IFN activation. 3/7