Project description:Severe acute respiratory syndrome (SARS) is a deadly form of pneumonia caused by a novel coronavirus, a viral family responsible for mild respiratory tract infections in a wide variety of animals including humans, pigs, cows, mice, cats, and birds. Analyses to date have been unable to identify the precise origin of the SARS coronavirus. We used Bayesian, neighbor-joining, and split decomposition phylogenetic techniques on the SARS virus replicase, surface spike, matrix, and nucleocapsid proteins to reveal the evolutionary origin of this recently emerging infectious agent. The analyses support a mammalian-like origin for the replicase protein, an avian-like origin for the matrix and nucleocapsid proteins, and a mammalian-avian mosaic origin for the host-determining spike protein. A bootscan recombination analysis of the spike gene revealed high nucleotide identity between the SARS virus and a feline infectious peritonitis virus throughout the gene, except for a 200- base-pair region of high identity to an avian sequence. These data support the phylogenetic analyses and suggest a possible past recombination event between mammalian-like and avian-like parent viruses. This event occurred near a region that has been implicated to be the human receptor binding site and may have been directly responsible for the switch of host of the SARS coronavirus from animals to humans.
Project description:BackgroundMonovalent Omicron XBB.1.5-containing vaccines were approved for coronavirus disease 2019 (COVID-19) 2023-2024 immunizations.MethodsThis ongoing, open-label, phase 2/3 study evaluated messenger RNA (mRNA)-1273.815 monovalent (50-µg Omicron XBB.1.5 spike mRNA) and mRNA-1273.231 bivalent (25-µg each Omicron XBB.1.5 and BA.4/BA.5 spike mRNAs) vaccines, administered as fifth doses to adults who previously received primary series, third doses of an original mRNA COVID-19 vaccine, and fourth doses of an Omicron BA.4/BA.5 bivalent vaccine. Interim safety and immunogenicity 29 days after vaccination are reported.ResultsParticipants (randomized 1:1) received 50-µg of mRNA-1273.815 (n = 50) or mRNA-1273.231 (n = 51); median intervals (interquartile range) from prior BA.4/BA.5 bivalent doses were 8.2 (8.1-8.3) and 8.3 (8.1-8.4) months, respectively. Fold increases in neutralizing antibody (nAb) against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants from prebooster nAb levels were numerically higher against XBB.1.5, XBB.1.16, EG.5.1, BA.2.86, and JN.1 than BA.4/BA.5, BQ.1.1, or D614G on day 29. Monovalent vaccine also cross-neutralized FL.1.5.1, EG.5.1, BA.2.86, HK.3.1, HV.1, and JN.1 variants in a participant subset (n = 20) 15 days after vaccination. Reactogenicity was similar to that of mRNA-1273 vaccines.ConclusionsXBB.1.5-containing mRNA-1273 vaccines elicit robust, diverse nAb responses against more recent SARS-CoV-2 variants, including JN.1, supporting the XBB.1.5-spike update for COVID-19 vaccines.
Project description:The SARS-CoV-2 Hydra with many heads (variants) has been causing the COVID-19 pandemic for 3 years. The appearance of every new head (SARS-CoV-2 variant) causes a new pandemic wave. The last in the series is the XBB.1.5 "Kraken" variant. In the general public (social media) and in the scientific community (scientific journals), during the last several weeks since the variant has appeared, the question was raised of whether the infectivity of the new variant will be greater. This article attempts to provide the answer. Analysis of thermodynamic driving forces of binding and biosynthesis leads to the conclusion that infectivity of the XBB.1.5 variant could be increased to a certain extent. The pathogenicity of the XBB.1.5 variant seems to be unchanged compared to the other Omicron variants.
Project description:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is being intensively studied, particularly its evolution, in the increasingly available sequences between countries/continents with classical phylogenetic tree representation. More recently, certain protein mutations have been correlated with specific functional impacts. Our clinical data from patients suggest that clinical symptoms differ between European countries. Among other factors, SARS-CoV-2 mutations could explain these disparities. Our analyses point to an association of diverse mutations, including co-evolving ones, in a few SARS-CoV-2 proteins within specific countries. We therefore suggest combining clinical information from patients and the determination of the associated SARS-CoV-2 genome to better understand the specific symptoms.
Project description:Diverse severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have emerged since the beginning of the COVID-19 pandemic. We investigated the immunological and pathological peculiarity of the SARS-CoV-2 beta variant of concern (VoC) compared to the ancestral strain. Comparative analysis of phenotype and pathology revealed that the beta VoC induces slower disease progression and a prolonged presymptomatic period in the early stages of SARS-CoV-2 infection but ultimately causes sudden death in the late stages of infection in the K18-hACE2 mouse model. The beta VoC induced enhanced activation of CXCL1/2-CXCR2-NLRP3-IL-1β signal cascade accelerating neutrophil recruitment and lung pathology in beta variant-infected mice, as evidenced by multiple analyses of SARS-CoV-2-induced inflammatory cytokines and transcriptomes. CCL2 was one of the most highly secreted cytokines in the early stages of infection. Its blockade reduced virus-induced weight loss and delayed mortality. Our study provides a better understanding of the variant characteristics and need for treatment. IMPORTANCE Since the outbreak of COVID-19, diverse SARS-CoV-2 variants have been identified. These variants have different infectivity and transmissibility from the ancestral strains. However, underlying molecular mechanisms have not yet been fully elucidated. In our study, the beta variant showed distinct pathological conditions and cytokine release kinetics from an ancestral strain in a mouse model. It was associated with higher neutrophil recruitment by increased levels of CXCL1/2, CXCR2, and interleukin 1β (IL-1β) at a later stage of viral infection. Our study will provide a better understanding of SARS-CoV-2 pathogenesis.
Project description:The newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with high transmission rates and striking immune evasion have posed a serious challenge to the application of current first-generation SARS-CoV-2 vaccines. Other sarbecoviruses, such as SARS-CoV and SARS-related coronaviruses (SARSr-CoVs), have the potential to cause outbreaks in the future. These facts call for the development of variant-proof SARS-CoV-2, pan-sarbecovirus or pan-β-CoV vaccines. Several novel vaccine platforms have been used to develop vaccines with broad-spectrum neutralizing antibody responses and protective immunity to combat the current SARS-CoV-2 and its variants, other sarbecoviruses, as well as other β-CoVs, in the future. In this review, we discussed the major target antigens and protective efficacy of current SARS-CoV-2 vaccines and summarized recent advances in broad-spectrum vaccines against sarbecoviruses and β-CoVs.
Project description:Circulation of SARS-CoV-2 Omicron XBB has resulted in the emergence of XBB.1.5, a new Variant of Interest. Our phylogenetic analysis suggests that XBB.1.5 evolved from XBB.1 by acquiring the S486P spike (S) mutation, subsequent to the acquisition of a nonsense mutation in ORF8. Neutralization assays showed similar abilities of immune escape between XBB.1.5 and XBB.1. We determine the structural basis for the interaction between human ACE2 and the S protein of XBB.1.5, showing similar overall structures between the S proteins of XBB.1 and XBB.1.5. We provide the intrinsic pathogenicity of XBB.1 and XBB.1.5 in hamsters. Importantly, we find that the ORF8 nonsense mutation of XBB.1.5 resulted in impairment of MHC suppression. In vivo experiments using recombinant viruses reveal that the XBB.1.5 mutations are involved with reduced virulence of XBB.1.5. Together, our study identifies the two viral functions defined the difference between XBB.1 and XBB.1.5.
Project description:BackgroundLike its predecessors in the XBB family, XBB.1.5 is highly immune evasive from therapeutic monoclonal antibodies and neutralizing antibodies generated by vaccination and/or infection. However, there is a lack of in vivo data on XBB.1.5 in animal models such as Syrian hamsters.MethodsSyrian hamsters (females) were used to examine airborne transmission along with virus replication of XBB.1.5 in naïve animals and human ACE2 hamsters with pre-existing immunity from a previous infection with Omicron BA.1. Assays were performed to determine neutralizing antibody responses, and virus titers were determined by standard plaque assays.FindingsUnlike earlier Omicron subvariants, such as BA.1 and BA.2, XBB.1.5 transmitted more efficiently in the hamster model. In addition, XBB.1.5 partially escaped BA.1-immunity from a previous infection with XBB.1.5 replicating in the nasal turbinate tissues and to a lesser extend in the lung tissues of previously infected hamsters.InterpretationOur in vivo data showing better airborne transmissibility of the Omicron subvariant XBB.1.5 than its predecessor, BA.2, in Syrian hamsters will allow researchers to further investigate amino acid substitutions that give XBB.1.5 a fitness advantage over BA.2 in transmission, data that may be important in studies of SARS-CoV-2 transmission in humans.FundingThis research is supported by grants from the Center for Research on Influenza Pathogenesis and Transmission (CRIPT; 75N93021C00014), funded by the National Institute of Allergy and Infectious Diseases and by a Research Program on Emerging and Reemerging Infectious Diseases (JP21fk0108552 and JP21fk0108615), a Project Promoting Support for Drug Discovery (JP21nf0101632), the Japan Program for Infectious Diseases Research and Infrastructure (JP22wm0125002), and The University of Tokyo Pandemic Preparedness, Infection and Advanced Research Center (UTOPIA) grant (JP223fa627001) from the Japan Agency for Medical Research and Development.