Figure 2.

Model of Kinetics of Alveolar Macrophage (AM) Immunosedation in Different Mouse Lung Environments.

In this model, the immunoreactivity of monocyte-derived AMs is determined by the lung environment and the duration spent in the lung. After lung insult or depletion of AMs, highly reactive monocytes are recruited into the lung and lose reactivity over time (immunosedation). In a non-inflamed lung (blue), the signals from the environment may be anti-inflammatory and therefore immunosedate these cells fast and efficiently, while activating stimuli are largely absent. In a still-inflamed lung environment (red), both pro- and anti-inflammatory signals may be present, leading to a slower rate of immunosedation. This might explain the comparably low immunoreactivity of monocyte-derived AMs after sterile depletion and the higher immunoreactivity for a longer time period following an inflammatory insult [10., 11., 12.,49]. This figure was created using BioRender (https://biorender.com/).