Resumen: Trained immunity (TI) represents a memory-like process of innate immune cells. TI can be initiated with various compounds such as fungal β-glucan or the tuberculosis vaccine, Bacillus Calmette-Guérin. Nevertheless, considering the clinical applications of harnessing TI against infections and cancer, there is a growing need for new, simple, and easy-to-use TI inducers. Here, we demonstrate that heat-killed Mycobacterium tuberculosis (HKMtb) induces TI both in vitro and in vivo. In human monocytes, this effect represents a truly trained process, as HKMtb confers boosted inflammatory responses against various heterologous challenges, such as lipopolysaccharide (Toll-like receptor [TLR] 4 ligand) and R848 (TLR7/8 ligand). Mechanistically, HKMtb-induced TI relies on epigenetic mechanisms in a Syk/HIF-1α-dependent manner. In vivo, HKMtb induced TI when administered both systemically and intranasally, with the latter generating a more robust TI response. Summarizing, our research has demonstrated that HKMtb has the potential to act as a mucosal immunotherapy that can successfully induce trained responses. Idioma: Inglés DOI: 10.1016/j.isci.2024.108869 Año: 2024 Publicado en: ISCIENCE 27, 2 (2024), 108869 [16 pp.] ISSN: 2589-0042 Factor impacto JCR: 4.1 (2024) Categ. JCR: MULTIDISCIPLINARY SCIENCES rank: 22 / 135 = 0.163 (2024) - Q1 - T1 Factor impacto SCIMAGO: 1.363 - Multidisciplinary (Q1)