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BCG revaccination in adults enhances pro-inflammatory markers of trained immunity along with anti-inflammatory pathways.

iScience

Authors: Asma Ahmed, Himanshu Tripathi, Krista E van Meijgaarden, Nirutha Chetan Kumar, Vasista Adiga, Srabanti Rakshit, Chaitra Parthiban, Sharon Eveline J, George D'Souza, Mary Dias, Tom H M Ottenhoff, Mihai G Netea, Simone A Joosten, Annapurna Vyakarnam

This study characterized mechanisms of Bacille Calmette-Guérin (BCG) revaccination-induced trained immunity (TI) in India. Adults, BCG vaccinated at birth, were sampled longitudinally before and after a second BCG dose. BCG revaccination significantly elevated tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, and IL-6 in HLA-DRCD16CD14 monocytes, demonstrating induction of TI. Mycobacteria-specific CD4 T cell interferon (IFN) γ, IL-2, and TNF-α were significantly higher in re-vaccinees and correlated positively with HLA-DRCD16CD14 TI responses. This, however, did not translate into increased mycobacterial growth control, measured by mycobacterial growth inhibition assay (MGIA). Post revaccination, elevated secreted TNF-α, IL-1β, and IL-6 to "heterologous" fungal, bacterial, and enhanced CXCL-10 and IFNα to viral stimuli were also observed concomitant with increased anti-inflammatory cytokine, IL-1RA. RNA sequencing after revaccination highlighted a BCG and LPS induced signature which included upregulated IL17 and TNF pathway genes and downregulated key inflammatory genes: . Our data highlight a balanced immune response comprising pro- and anti-inflammatory mediators to be a feature of BCG revaccination-induced immunity.

© 2023 The Authors.

PMID: 37817935

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