Figure 1.

Classical in vitro model of trained immunity. Trained immunity describes a functional, metabolic and epigenetic adaptation of innate immune cells to previous stimuli with ensuing increased immune response, i.e. cytokine release, to secondary stimulation. (A) The classical model applies the Dectin-1 agonist β-1,3-D Glucan as the first stimulus and the TLR-4 agonist LPS as the second stimulus. (B) The basis for β-1,3-D Glucan induced trained immunity are metabolic adaptations, including the mTOR signal-transduction enhanced glycolysis. Interrupted errors indicate that many more proteins are involved in the signaling cascade, which are not depicted in the figure.