Fig 1.

Interaction classifications. On the y axis, production of a cytokine is depicted. On the x axis, the ligands (A and B) used to stimulate the PBMCs are depicted; PBMCs were stimulated with either a single ligand or a combination of two PRR ligands. To identify a synergistic effect, the cytokine production after stimulation with both ligands combined should be higher than the combined values of the two single effects. An inhibitory effect was defined as a cytokine response to a combination of ligands that was maximally 0.75-fold of the sum of the cytokine responses to either of the individual ligands and lower than the cytokine response to a single ligand or to both of the ligands. A cytokine production of the combination of stimuli higher than production of each of the single stimulations, but not higher than the sum of the two, is considered additive and is thus classified as “no effect/additive effect.”