Accurate evaluation of live-virus microneutralisation for SARS-CoV-2 variant JN.1 in the assessment of vaccination and therapeutics.
Creators: name: Dowgier, Giulia
name: Hobbs, Agnieszka
name: Greenwood, David
name: Shawe-Taylor, Marianne
name: Stevenson-Leggett, Phoebe
name: Bazire, James
name: Penn, Rebecca
name: Harvey, Ruth
name: Crick COVID serology pipeline, Legacy Investigators
name: Libri, Vincenzo
name: Kassiotis, George
name: Gamblin, Steve
name: Lewis, Nicola S
name: Williams, Bryan
name: Swanton, Charles
name: Gandhi, Sonia
name: Bauer, David LV
name: Carr, Edward J
name: Wall, Emma C
name: Wu, Mary Y
Publisher: name: The Francis Crick Institute
Year: 2025
Subjects: classificationCode: Tumour Biology
subject: Tumour Biology
classificationCode: Stem Cells
subject: Stem Cells
classificationCode: Signalling & Oncogenes
subject: Signalling &amp; Oncogenes
classificationCode: Chemical Biology & High Throughput
subject: Chemical Biology &amp; High Throughput
classificationCode: Ecology,Evolution & Ethology
subject: Ecology,Evolution &amp; Ethology
classificationCode: Infectious Disease
subject: Infectious Disease
classificationCode: Immunology
subject: Immunology
subject: FOS: Clinical medicine
classificationCode: Genetics & Genomics
subject: Genetics &amp; Genomics
classificationCode: Metabolism
subject: Metabolism
classificationCode: Computational & Systems Biology
subject: Computational &amp; Systems Biology
classificationCode: Genome Integrity & Repair
subject: Genome Integrity &amp; Repair
classificationCode: Neurosciences
subject: Neurosciences
classificationCode: Human Biology & Physiology
subject: Human Biology &amp; Physiology
classificationCode: Model organisms
subject: Model organisms
classificationCode: Structural Biology & Biophysics
subject: Structural Biology &amp; Biophysics
classificationCode: Cell Biology
subject: Cell Biology
classificationCode: Imaging
subject: Imaging
classificationCode: Cell Cycle & Chromosomes
subject: Cell Cycle &amp; Chromosomes

description: Emerging SARS-CoV-2 variants require rapid assessments of pathogenicity and evasion of existing immunity to inform policy. A crucial component of these assessments is accurate estimation of serum neutralising antibody titres using cultured live virus isolates. Here, we report a comparison of culture methods for Omicron sub-variant JN.1 and the subsequent evaluation of neutralising antibody titres (nAbTs) in recipients of BNT162b2-XBB.1.5 monovalent and the ancestral/BA.4/5 containing bivalent vaccines. We compared culture of JN.1 in either Vero V1 cells or Caco-2 cells, finding culture in Vero V1 either resulted in low-titre stocks or induced crucial mutations at the Spike furin cleavage site (FCS). Using sequence-clean culture stocks generated in Caco-2 cells, we assessed serum samples from 71 healthy adults eligible for a COVID-19 vaccination given as a 5th dose booster in the UK: all participants had detectable nAbs against JN.1 prior to vaccination, with baseline/pre-existing nAbTs between both vaccine groups comparable (p = 0.240). However, nAbTs against JN.1 post-vaccination were 2.6-fold higher for recipients of the monovalent XBB.1.5 vaccine than the BA.4/5 bivalent vaccine (p &lt; 0.001). Further, at clinically relevant concentrations the therapeutic monoclonal antibody Sotrovimab marginally maintains neutralisation of JN.1. Regular re-appraisal of methods and policy outcomes as new variants arise is required to ensure robust data are used to underpin future severity assessments and vaccine strain selection decisions.