Trained immunity is the ability of our innate immune cells, once they have been exposed to a first pathogen (or vaccine), to undergo a process of metabolic and epigenetic reprogramming that prepares them to respond better to a second infection, whether with the same pathogen or with any other pathogen.
After a second infection, the immune response is:
More potent and sustained over time than that produced after the first contact.
It generates high production of inflammatory cytokines:
- TNF-alpha
- IL-1beta
- IL-6
Trained innate immunity enhances the response to infection and vaccination, facilitating stronger innate immune responses and greater protection against a variety of microbial stimuli.
It provides a high level of protection against infection.
Therefore, TIbVs are characterised by conferring a non-specific resistance to Ags that depends directly on the stimulation of trained immunity, in addition to a specific resistance to Ags that depends on adaptive immunity : Generating broader protection.
Figure 1. Vaccines based on Innate Trained Immunity
Treatment with vaccines:
- Confers broader protection, not only against the pathogens contained in vaccines, but also against other pathogens.
- Generates medium/long-term immunological memory in the individual.
- Activation of innate immune cells improves host defence by developing a trained immunity.
- Enhances the function of innate and adaptive immune responses.
Bibliography:
- Netea et al. (2015) Nat Immunol.
- Sánchez-Ramón et al. (2018) Frontiers in inmunology.
- Domínguez-Andrés J, Dos Santos JC, Bekkering S, Mulder WJM, van der Meer JWM, Riksen NP, Joosten LAB, Netea MG. Trained immunity: adaptation within innate immune mechanisms. Physiol Rev. 2023 Jan 1;103(1):313-346. doi: 10.1152/physrev.00031.2021. Epub 2022 Aug 18. PMID: 35981301.
- Sánchez-Ramón S, Conejero L, Netea MG, Sancho D, Palomares Ó, Subiza JL. Trained Immunity-Based Vaccines: A New Paradigm for the Development of Broad-Spectrum Anti-infectious Formulations. Front Immunol. 2018 Dec 17;9:2936. doi: 10.3389/fimmu.2018.02936. PMID: 30619296; PMCID: PMC6304371.
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