# Mouse monocytes express CD127 by immune cells, not LPS

## TL;DR

Mouse monocytes can express CD127, but this is controlled by immune cells and not by LPS, differing from human behavior.

## Contribution

The study reveals that CD127 expression in mouse monocytes is inducible and regulated by immune cells, not LPS.

## Key findings

- CD127 expression in mouse monocytes/macrophages is inducible and depends on other immune cells.
- IL-7 downregulates CD127 expression, showing it is functional in these cells.
- CD127 expression decreases during inflammation in vivo.

## Abstract

The essential role of interleukin 7 (IL-7) signaling via its receptor (IL-7Rα; CD127) in T cell development and function has been well documented. However, CD127 expression and function in myeloid cells, including monocytes, are less clear, especially in mice. In the present study we report an inducible CD127 expression in mouse monocytes/macrophages. This induction is dependent on the presence of other immune cells, highlighting that regulation of CD127 expression on monocytes differs in mice and humans. We demonstrate that CD127 is functional, as IL-7 downregulated its expression. We also saw decreased CD127 expression during inflammation in vivo. Overall, upregulation of CD127 expression in vitro and its downregulation in vivo confirm that CD127 is an inducible marker on mouse monocyte/macrophage cells, in contrast to findings recently published by others. Characterizing the role of CD127 signaling in myeloid cells in inflammatory disorders would be worthwhile in future study.