Recovery training or over-training? The contribution of TLR10 to monocyte fitness.

The concept of trained immunity refers to remodelling of the monocyte and macrophage metabolic and epigenetic landscape, conferring an amplified inflammatory response upon secondary stimulation. This effect is typically modelled in vitro by stimulating monocytes with either Bacillus Calmette Guerin (BCG) or β-Glucan for 24 hr, before subsequent stimulation with LPS or Pam-3-Cys (P3C) as a secondary stimulus 6 days later. Here, we focus on a recent paper which interrogated the role of the anti-inflammatory TLR, TLR10, on trained immunity. Using both an in vitro model of trained immunity, and analysis of BCG vaccinated individuals, the authors interestingly demonstrate that, despite its ability to regulate aspects of innate immunity, TLR10 does not have a significant role in this process.