Hang, S. K. | bioRxiv Science

bioRxiv2025

Heterogeneous T cell response patterns within established clinical phases of Hepatitis B infection revealed through the rapid functional characterization of HBV-specific T cells in whole blood

Background & AimsThere is an unmet need for immunological biomarkers in chronic hepatitis B (CHB), where patient management relies on virological and biochemical markers despite the crucial role of virus-specific T cells in controlling viral replication and disease progression. To address this, we developed the HBV-cytokine release assay (HBV-CRA), a rapid, point-of-care test that measures multiple cytokines in whole blood after HBV-peptide stimulation. MethodsWe first assessed the assays sensitivity by spiking whole blood with engineered HBV-specific T cells. Next, we compared sensitivity and consistency of HBV-CRA to ex vivo IFN-{gamma} ELISpot assays. We then applied the assay in a cross-sectional study of 235 CHB patients and longitudinally in acute HBV patients during HBsAg sero-clearance. ResultsThe HBV-CRA detected T cell function in 80% of CHB cases and showed that elevated IL-2 and IFN-{gamma} levels after Core peptide stimulation were associated with HBsAg clearance. Importantly, unsupervised clustering identified distinct immune response patterns independent of established clinical and virological classifications. The assay also demonstrated the functional impact of NUC treatment on HBV-specific T cell responses. ConclusionsThe HBV-CRA is a rapid and easy-to-use assay that identifies immune profiles associated with HBsAg clearance and differentiates CHB patients based on antiviral T cell function. Its application in a large CHB cohort revealed that traditional disease phase classifications, based on viral and clinical parameters, cannot predict HBV-specific T cell profiles. The HBV-CRA has the potential to guide patient stratification for immunotherapeutic interventions.

immunology↗

bioRxiv2022

Mutations of SARS-CoV-2 variants of concern escaping Spike-specific T cells

The amino acid (AA) mutations that characterise the different variants of concern (VOCs), which replaced the ancestral SARS-CoV-2 Wuhan-Hu-1 isolate worldwide, provide biological advantages such as increased infectivity and partial escape from humoral immunity. Here we analysed the impact of these mutations on vaccination- and infection-induced Spike-specific T cells. We confirmed that, in the majority of infected or vaccinated individuals, different mutations present in a single VOC (Delta) or a combined mosaic of more than 30 AA substitutions and deletions found in Alpha, Beta, Gamma, Delta and Omicron VOCs cause modest alteration in the global Spike-specific T cell response. However, distinct numerically dominant Spike-specific CD4 and CD8 T cells preferentially targeted regions affected by AA mutations and do not recognise the mutated peptides. Importantly, some of these mutations, such as N501Y (present in Alpha, Beta, Gamma, and Omicron) and L452R (present in Delta), known to provide biological advantage to SARS-CoV-2 in terms of infectivity also abolished CD8 T cell recognition. Taken together, our data show that while global mRNA vaccine- and infection-induced Spike-specific T cells largely tolerate the diverse mutations present in VOCs, single Spike-specific T cells might contribute to the natural selection of SARS-CoV-2 variants.

immunology↗