Tuberculosis alters immune-metabolic pathways resulting in perturbed IL-1 responses

Abstract

Tuberculosis (TB) remains a major public health problem with host-directed therapeutics offering potential as novel treatment strategies. However, their successful development still requires a comprehensive understanding of how Mycobacterium tuberculosis (M.tb) infection impacts immune responses. To address this challenge, we applied standardised immunomonitoring tools to compare TB antigen, BCG and IL-1{beta} induced immune responses between individuals with latent M.tb infection (LTBI) and active TB disease, at diagnosis and after cure. This revealed distinct responses between TB and LTBI groups at transcriptomic, proteomic and metabolomic levels. At baseline, we identified pregnane steroids and the PPAR{gamma} pathway as new immune-metabolic drivers of elevated plasma IL-1ra in TB. We also observed dysregulated induced IL-1 responses after BCG stimulation in TB patients. Elevated IL-1 antagonist responses were explained by upstream differences in TNF responses, while for IL-1 agonists it was due to downstream differences in granzyme mediated cleavage. Finally, the immune response to IL-1{beta} driven signalling was also dramatically perturbed in TB disease but was completely restored after successful antibiotic treatment. This systems immunology approach improves our knowledge of how immune responses are altered during TB disease, and may support design of improved diagnostic, prophylactic and therapeutic tools.