Our Work

Harris JM, Lok J, Wand N, Magri A, Tsukuda S, Wu Y, Ng E, Jennings D, Elshenawy B, Balfe P, and McKeating JA.

Nature Communications (2025)

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Abstract :

Hepatitis B virus (HBV) is a small DNA virus that establishes chronic infection and drives progressive liver disease and cancer; presenting a global health problem with more than 250 million infections. HBV replicates via an episomal covalently-closed-circular DNA (cccDNA) and integrated viral DNA fragments are linked to carcinogenesis. Current treatments only suppress HBV replication and there is a global initiative to develop genome targeting therapies, including siRNAs, antisense oligonucleotides and epigenetic modifiers specific for HBV cccDNA. However, our knowledge of the cccDNA and integrant transcriptomes is confounded by overlapping viral RNAs. Using targeted long-read sequencing we mapped the HBV transcriptome in liver biopsies from eleven treatment naïve patients. Probe enrichment yielded robust sequencing libraries and identified cccDNA-derived genomic and sub-genomic transcripts, and a repertoire of previously uncharacterised spliced, truncated and chimeric viral RNAs. Assigning viral transcripts to their respective DNA templates revealed differential promoter activity in cccDNA and integrants, with implications for the efficacy of epigenetic modifiers. Integrant-derived transcripts showed vast diversity in the viral-host junctions, posing a challenge for current nucleotide-targeting therapies. cccDNA was a source of genetic polymorphism, with distinct viral lineages present in the surface antigen encoding region, providing an insight into hepadnavirus evolution during chronic infection.

Liu G, Antoun E, Fries A, Yao X, Yin Z, Dong D, Wang W, Wing PAC, Dejnirattisa W, Supasa P, Liu C, Rostron T, Waugh C, Clark K, Sopp P, Fry JW, Vendrell I, McKeating JA, Mongkolsapaya J, Screaton GR, Kessler BM, Fisher R, Ogg G, Mentzer AJ, Knight JC, Peng Y, and Dong T.

Nature Communications (2025)

Link to publication

Abstract :

The recent COVID-19 pandemic left behind the lingering question as whether new variants of concern might cause further waves of infection. Thus, it is important to investigate the long-term protection gained via vaccination or exposure to the SARS-CoV-2 virus. Here we compare the evolution of memory T-cell responses following primary infection with subsequent antigen exposures. Single-cell TCR analysis of three dominant SARS-CoV-2 spike-specific CD4+ T-cell responses identifies the dominant public TCRα clonotypes pairing with diverse TCRβ clonotypes that associated with mild disease at primary infection. These clonotypes are found at higher frequencies in pre-pandemic repertoires compared to other epitope-specific clonotypes. Longitudinal transcriptomics and TCR analysis, combined with functional evaluation, reveals that the clonotypes persisting 3–4 years post initial infection exhibit distinct functionality compared to those that were lost. Furthermore, spike-specific CD4+ T cells at this time point show decreased Th1 signatures and enhanced GZMA-driven cytotoxic transcriptomic profiles that were independent of TCR clonotype and associated with viral suppression. In summary, we identify common public TCRs used by immunodominant spike-specific memory CD4+ T-cells, associated with mild disease outcome, which likely play important protective roles to subsequent viral infection events.