Search

Objectives: Bacille Calmette-Guérin (BCG) vaccination has off-target effects on disease risk for unrelated infections and immune responses to vaccines. This study aimed to determine the immunomodulatory effects of BCG vaccination on immune responses to vaccines against SARS-CoV-2., Methods: Blood samples, from a subset of 275 SARS-CoV-2-naïve healthcare workers randomised to BCG vaccination (BCG group) or no BCG vaccination (Control group) in the BRACE trial, were collected before and 28 days after the primary course (two doses) of ChAdOx1-S (Oxford-AstraZeneca) or BNT162b2 (Pfizer-BioNTech) vaccination. SARS-CoV-2-specific antibodies were measured using ELISA and multiplex bead array, whole blood cytokine responses to γ-irradiated SARS-CoV-2 (iSARS) stimulation were measured by multiplex bead array, and SARS-CoV-2-specific T-cell responses were measured by activation-induced marker and intracellular cytokine staining assays., Results: After randomisation (mean 11 months) but prior to COVID-19 vaccination, the BCG group had lower cytokine responses to iSARS stimulation than the Control group. After two doses of ChAdOx1-S, differences in iSARS-induced cytokine responses between the BCG group and Control group were found for three cytokines (CTACK, TRAIL and VEGF). No differences were found between the groups after BNT162b2 vaccination. There were also no differences between the BCG and Control groups in COVID-19 vaccine-induced antigen-specific antibody responses, T-cell activation or T-cell cytokine production., Conclusion: BCG vaccination induced a broad and persistent reduction in ex vivo cytokine responses to SARS-CoV-2. Following COVID-19 vaccination, this effect was abrogated, and BCG vaccination did not influence adaptive immune responses to COVID-19 vaccine antigens., Competing Interests: Outside the submitted work, JC has received grants or contracts from Valneva/Butantan, MSD, Sanofi Pasteur, CEPI/Sabin Institute, Takeda and NIH; payment or honoraria for presentations from Pfizer and is on the Brazil and/or Latin America Advisory Boards for Modern/Zodiac, Pfizer and Takeda. MGN is a scientific founder of Lemba, Biotrip and TTxD. All other authors declare no conflicts of interest., (© 2025 The Author(s). Clinical & Translational Immunology published by John Wiley & Sons Australia, Ltd on behalf of Australian and New Zealand Society for Immunology, Inc.)

Type I interferons (IFN1s) mediate innate responses to microbial stimuli and regulate interleukin (IL)-1 and IL-1 receptor antagonist (Ra) production in human cells. This study explores interferon-stimulated gene (ISG) alterations in the transcriptome of patients with gout and stimulated human primary cells in vitro in relation to serum urate concentrations. Peripheral blood mononuclear cells (PBMCs) and monocytes of patients with gout were primed in vitro with soluble urate, followed by lipopolysaccharide (LPS) stimulation. Separately, PBMCs were stimulated with various toll-like receptor (TLR) ligands. RNA sequencing and IL-1Ra cytokine measurement were performed. STAT1 phosphorylation was assessed in urate-treated monocytes. Cytokine responses to IFN-β were evaluated in PBMCs cultured with or without urate and restimulated with LPS and monosodium urate (MSU) crystals. Transcriptomics revealed suppressed IFN-related signalling pathways in urate-exposed PBMCs or monocytes which was supported by diminishment of phosphorylated STAT1. The stimulation of PBMCs with IFN-β did not modify the urate-induced inflammation. Interestingly, in vivo, serum urate concentrations were inversely correlated to in vitro ISG expression upon stimulations with TLR ligands. These findings support a deficient IFN1 signalling in the presence of elevated serum urate concentrations, which could translate to increased susceptibility to infections., (© 2024 The Author(s). Immunology published by John Wiley & Sons Ltd.)