Erysipelas in laying chickens [Japan] Shibatani, M. (Hyogo-ken. Government Office, Kobe (Japan)); Imoto, H; Kannan, M ...
Journal of the Japanese Society of Poultry Diseases (Japan),
(Sep 1983), Letnik:
19, Številka:
3
Journal Article
Outbreaks of purulent arthritis in layer chicknes Shibatani, M; Imoto, H; Naito, I. (Hyogo-ken. Government Office, Kobe (Japan)) ...
Journal of the Japanese Society of Poultry Diseases (Japan),
(Dec 1982), Letnik:
18, Številka:
4
Journal Article
In late 2022, SARS-CoV-2 Omicron subvariants have become highly diversified, and XBB is spreading rapidly around the world. Our phylogenetic analyses suggested that XBB emerged through the ...recombination of two cocirculating BA.2 lineages, BJ.1 and BM.1.1.1 (a progeny of BA.2.75), during the summer of 2022. XBB.1 is the variant most profoundly resistant to BA.2/5 breakthrough infection sera to date and is more fusogenic than BA.2.75. The recombination breakpoint is located in the receptor-binding domain of spike, and each region of the recombinant spike confers immune evasion and increases fusogenicity. We further provide the structural basis for the interaction between XBB.1 spike and human ACE2. Finally, the intrinsic pathogenicity of XBB.1 in male hamsters is comparable to or even lower than that of BA.2.75. Our multiscale investigation provides evidence suggesting that XBB is the first observed SARS-CoV-2 variant to increase its fitness through recombination rather than substitutions.
Abstract
The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variants has led to concerns that ancestral SARS-CoV-2-based vaccines may not be effective against newly ...emerging Omicron subvariants. The concept of “imprinted immunity” suggests that individuals vaccinated with ancestral virus-based vaccines may not develop effective immunity against newly emerging Omicron subvariants, such as BQ.1.1 and XBB.1. In this study, we investigated this possibility using hamsters. Although natural infection induced effective antiviral immunity, breakthrough infections in hamsters with BQ.1.1 and XBB.1 Omicron subvariants after receiving the 3-dose mRNA-lipid nanoparticle vaccine resulted in only faintly induced humoral immunity, supporting the possibility of imprinted immunity.
The emergence of SARS-CoV-2 Omicron XBB subvariants raises vaccine effectiveness concerns. Our hamster model demonstrated that ancestral virus-based vaccines failed to produce effective neutralizing antibodies against Omicron subvariants (eg, BQ.1.1, XBB.1) during breakthrough infections, supporting the concept of imprinted immunity.
Most studies investigating the characteristics of emerging SARS-CoV-2 variants have been focusing on mutations in the spike proteins that affect viral infectivity, fusogenicity, and pathogenicity. ...However, few studies have addressed how naturally occurring mutations in the non-
regions of the SARS-CoV-2 genome impact virological properties. In this study, we proved that multiple SARS-CoV-2 Omicron BA.2 mutations, one in the spike protein and another downstream of the
gene, orchestrally characterize this variant, shedding light on the importance of Omicron BA.2 mutations out of the spike protein.
